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This is to certify that the

thesis entitled

SURFACE SULFONATION OF POLYMERS
TO IMPART SELECTED BARRIER
PROPERTIES

presented by

JING Y. ZHU

has been accepted towards fulfillment
of the requirements for

Master degreein School of Packaging

 

 

(Science)

 

 

 

 

 

 

Major professor

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University

 

 

 

 

 

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SURFACE SULFONATION OF POLYMERS TO IMPART SELECTED

BARRIER PROPERTIES

BY

Jing Y. Zhu

A THESIS
Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of
Master of Science
School of Packaging

1995

ABSTRACT

SUREACE SULFONRTIGN OF POLYMERS TO IMPART
SELECTED BARRIER PROPERTIES

BY

Jing Y. Zhu

The PP films were sulfonated at three different time. The two
counterions, ammonium (NHJ) and.sodium.(Na7), were used to
neutralized the sulfonated PP at different sulfonation time. ESCA
was used to determine the surface compositions of the films. The
permeation of oxygen, carbon dioxide and water vapor into the
sulfonated PP films were studied in this research. There are
there different temperature and two relative humidity were used
to determine the oxygen permeation. Unmodified PP specimens were

evaluated through the study for comparison purpose.

To Hy Parent.

ACKNOWLEDGEMENTS

There are many people who I wish to thank for both their
help and support in completing this project. Firstly, I
would like to thank my advisor, Dr. Hernandez, for his
patience and helpful advice. Through his guidance I have
learned observe, not see.

I must say a very big thank you to the staff at the
Composite Materials and Structures Center. Brian Erickson
spent an incredible amount of time working with me to
sulfonate films. Dan Hook help me to do the ESCA analysis.
I also like to thank Dr. Jack Gaicin and Dr. Pinnavaia for
your support and suggestion.

Finally, I must thank my parents, Yi and Qi-Xio Zhu, for

their love and support.

IV

 

TABLE OF CONTENT

Page
LIST OF TABLES ...................................... VI
LIST OF FIGURES ..................................... VII
INTRODUCTION ........................................ 1
LITERATURE REVIEW ................................... 3
Polypropylene Characteristics ....................... 3
Sulfonation ......................................... 6
2.1 Sulfonation Reagents ............................ 6
2.2 Sulfonation Reaction ............................ 8
2.3 Neutralization .................................. 10
2.4 Previous Studies ................................ 11
2.4.1 Reaction of The Sulfonation
Polymer Surface ........................... 11
2.4.2 Effect on Electrical and
Physical Properties .................... -.. 12
2.4.3 Effect on Mechanical Properties ........... 12
2.4.4 Effect on The Barrier Properties .......... 13
Permeability ........................................ 16
3.1 Introduction .................................... 16
3.2 Permeability Measurement ........................ 18
3.2.1 Isostatic Method .......................... 18
3.2.2 Quasi-Isostatic Method .................... 21
3.2.3 Absolute Pressure Method .................. 23
MATERIALS AND METHODOLOGY ........................... 24
Sulfonation ......................................... 24

4.2 Sulfonation Unit ................................ 25
4.3 Experiment Procedure ............................ 27
4.3.1 Cleaning Procedure ........................ 28
4.3.2 Sulfonation Procedure ..................... 28
4.3.3 Neutralization Procedure .................. 29
4.3.4 Ion Exchanging Procedure .................. 30
PERMEABILITY MEASUREMENT ............................ 31

5.1 Electron Spectroscopy for

Chemical Analysis (ESCA) ........................ 31
5.2 Oxygen Permeability Measurement ................. 31
5.3 Carbon Dioxide Permeability Measurement ......... 33
5.4 Water Vapor Permeability Measurement ............ 33
RESULT AND DISCUSSION ............................... 36
6.1 Sulfonation ..................................... 36

6.1.1 Quantitative Chemical Analysis by ESCA .... 36

6.1.2 5C5 Gas Reacting and Diffusion with PP .... 41

6.2 Oxygen Permeation Study ......................... 45
6.2.1 Film neutralized with NH; ................ 45
6.2.2 Sulfonation PP ion neutralized by Na‘ ..... 58

6.3 CO2 Permeability Studies ........................ 62

6.4 Water Vapor Permeation Studies .................. 68

EXPERIMENTAL ERROR .................................. 73

SUMMARY AND CONCLUSIONS ............................. 76

APPENDICES .......................................... 77

BIBLIOGRAPHY ........................................ 82

Table

1.1 Major properties of Polypropylene ..............

6.1

LIST OF TABLE

Percent atomic composition of PP sulfonated
from O to 3 minutes as obtained by ESCA on the
surface

Relative atomic ratios of sulfonated PP
films on the surface

Depth of the sulfonation of the sulfonated
PP films at different sulfonation time

Ch permeability of sulfonated PP with 0%RH
at 13°C, 26°C and 35°C, neutralized with NHfi'

Activation energy of the oxygen permeability

as a function of sulfonation degree of PP ......

Diffusion coefficient of sulfonated PP at
13°C, 26°C and 35°C with 0%RH, neutralized
with NHf'

CL solubility of sulfonated PP at 13°C, 26°C
and 35°C at 0%RH, neutralized with NHf'

Oxygen permeability and diffusion coefficient
of the sulfonation layers of the sulfonated
PP films

(3 permeability of sulfonated PP at 26°C at
76%RH and neutralized with NH:'

(5 Diffusion Coefficient of sulfonated PP
at 26°C, 70%RH, neutralized with NHf'

solubility of sulfonated PP at 26°C,
75%RH, neutralized with NH;'

02 permeability of the sulfonated PP ion
exchanged by Na.‘at 13°C, 26°C and 35°C
with 0%RH

Oz Diffusion coefficient of sulfonated PP
ion exchanged by Na.‘at 13°C, 26°C and 35°C
with 0%RH

Ch solubility of sulfonated PP ion exchanged

by Naf‘at 13°C, 26°C and 35°C with 0%RH ........

-VII

OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

........

Page

36

37

44

46

48

52

54

57

59

59

60

65

65

66

Table Page

6.15 Crb permeability of the sulfonated PP
neutralized with NHf'at 25°C at 0%RH .......... 71

6.16 Water vapor permeability of the sulfonated
PP at 27°C, 33°C and 37.8°C .................... 71

VIII

LIST OF FIGURES

Figure

2

2

.1

.2

.1

Sulfonation Reaction Scheme of PE ...............

Typical Transmission Rate Profile Curve for
Isostatic Procedure .............................

Typical Transmission Rate Profile Curve for
Quasi-Isostatic Procedure .......................

Schematic Diagram of Sulfonation System .........
Schematic of Sulfur Trioxide Procedure Process

Schematic Diagram of Oxygen Permeability
Test System .....................................

Schematic Diagram of Water Activity Control
System ..........................................

Schematic Diagram of Carbon Dioxide
Permeability Test System ........................

Schematic Diagram of Water Vapor
Permeability Test System ........................

Sulfur Concentration on the Film Surface as
a Function of Sulfonation Time ..................

Percentage Weight of Sulfur on the Surface

of the sulfonate ed PP Films, of the Sulfonated
PP Films, and Percentage Weight Change of the
Sulfonated PP Film vs Sulfonation Time ..........
Sulfonation Reaction Scheme of PP ...............

C) permeability of sulfonated PP at 13°C,
2 °C and 35°C with 0%RH (NHf) ..................

Activation energy of the oxygen permeability
as a function of sulfonation degree of PP .......

(D diffusion coefficient of sulfonated PP at
1 °c, 26°C and 35°C with 0%RH (1mg) ............

IX

26

27

32

32

35

35

47

49

53

.10

.11

.12

.13

.14

O2 solubility of sulfonated PP at 13°C, 26°C

and 35°C at 0%RH (NHJ) ......................... 55
Comparison of Oz permeability of sulfonated

99 at 26°C with 0%RH and 70%RH (my) ............ 61
Comparison of O2 diffusion coefficient of

sulfonated PP at 26°C with 0%RH and
70%RH (NH,*) .................................... 62

Comparison of O2 solubility of the
sulfonated PP at 26°C with 0%RH and
70%RH (NI-I") .................................... 63

Comparison of Oz permeability of the
sulfonated PP ion exchanged by NH" and
Na’ at 13°C, 26°C and 35°C with 0%RH ............ 67

Comparison of O diffusion coefficient of
the sulfonated PP ion exchanged by Na’ and
NH; at 13°C, 26°C and 35°C with 0%RH ........... 68

Comparison of O solubility of the sulfonated
PP ion exchangeé by Na, and NH" at 13°C, 26°C
and 35°C with O’cRH .............................. 69

cog permeability of the sulfonated PP at
25 c with 0%RH (NI-I") ........................... 72

INTRODUCTION

Over the past decades, the importance of high barrier
polymers in the areas of food and pharmaceutical packaging
has grown at a very accelerated rate due to considerations
of convenience and economy. Most synthetic polymers are used
in packaging materials for food, pharmaceutical, and related
products. Polyolefin, such as PE and PP, has excellent water
barrier, but has a high oxygen permeability so that foods
and medicines packaged in these materials suffer oxidation,
discoloration, loss of taste aroma, etc. Conversely, some
polar polymers, containing hydrophilic groups, have an
excellent gas barrier when dry but have very poor water or
gas barrier when containing water.

In recent years, much attention has been focused on chemical
modification of the surface of polymers, and the effect of
such a treatment on the polymers barrier properties.

Walles (1989) described the effect of surface sulfonation on
the barrier properties of a high density polyethylene (HDPE)
article and showed that sulfonation, followed by air purging
and neutralization with NH3 gas, resulted in an excellent
organic vapor barrier, at a surface concentration of between
75-200 pg SOflkmF surface area. The oxygen barrier
properties of sulfonated PE were found to be strongly
dependent upon the nature of the counterion" NP. For

example, Walles (1989) reported that Naf as the counterion

2

was 6 times as effective as NHf'in providing a barrier to

oxygen diffusion. Lithium ion (1d?) was 12 times better than

NHf} all at a surface concentration of about 70 pg SOykmf

surface area, which for a 25 pm film equals about 1% bulk

sulfur.

This study focuses specifically on determining the barrier

properties of oxygen and water vapor of sulfonated polymer

films neutralized with NH; and Na". The study included the
effect of relative humidity on the permeability.

The objectives of this study were:

1. To determine the permeation of oxygen, carbon dioxide and
water vapor into the sulfonated PP films. Unmodified PP
specimens were evaluated throughout the study for
comparison purpose.

2. To determine the effect on the oxygen permeability value
between ammonium (NHf) and sodium (Na?) counterions, at
different sulfonation time.

3. To determine the oxygen permeation of the sulfonated PP
films at high relative humidity, compared with dry

condition.

LITERATURE REVIEW

POLYPROPYLENE CHARACTERISTICS

Polypropylene (PP), a thermoplastic material, was first
commercialized in 19508. PP is a versatile material, with
major applications in automobile parts, textiles,
appliances, films and packaging. By 1992, the production of
PP rose 36% to 9.4 billion 1b. Despite the estimates of slow
demand, analysts predicted that PP would continue to grow on
the order of 6% per year.

Polypropylene is made by the catalytic polymerization of
propylene monomer under heat and pressure. The chemical

structure of polypropylene is as follows:

‘in
‘[ CH— CH ]—
1’1

Monomer unit of Polypropylene
There are three possible stereo-figuration of PP, isotactic,
syndiotactic and atactic, depending upon the disposition of
the pendant methyl group with respect to the main chain
(Miller, 1986). In the isotactic configuration, all the
methyl groups are on the same side of the chain; in the

syndiotactic, they alternate regularly; in the atactic, the

3

4
disposition is random. The properties of these
configurations differ greatly. Atactic PP is amorphous,
while the isotactic and syndiotactic are semi—crystalline.
Commercially available polypropylenes are partially
crystalline products. The polypropylene films are widely use
in the food packaging. Initially, Polypropylene films were
laminated with cellophane to overcome flex-cracking and to
provide toughness. Polypropylene eventually replaced many
other films, particularly barrier-coated cellophane, as its
economy and excellent physical properties became fully
recognized. The density of PP ranges between 0.88 and 0.91
g/cc - one of the lowest among polymers, and their melting
temperature range between 160 and 178 °C. This allows foods
and pharmaceutical products packaged in polypropylene to be
heat-sterilized inside the package which is not the case
with PE (Giacin, 1992). Table 1.1 summarizes the properties
of the polypropylene produced by cast extrusion and

biaxially oriented.

Table 1.1 major properties of polypropylene (Mbdern

Plastics, Encyclopedia’94)

fl

 

 

 

Extrusion Biaxially

(cast) Oriented
_§pecific Gravity (g/cc) 0.885-0.905 0.902-0.907
Tensile Strength (p.s.i.) 4500-10,000 7500-40,000
Elongation % 550-1000 35-475

 

Rate of water vapor
transmission (g.mil/100 0.7 0.25-0.4
sq.in. 24 h) at 37.8°C

 

C5 trans. rate (cc.mi1/100 150-240 100-160
sq.in. 24 h) at 25°C . -

CO2 trans. rate (cc.mil/100 500-800 540
sq.in.24 h) at 25°C

 

 

 

Dielectric constant 2.2 2.2
1 Khz

 

 

 

SULFONATIGN

A method used to modify the surface of polymeric films
include exposing the films to a reactive gas. This method
has been used with fluorine gas, chlorine gas, and sulfur
trioxide to obtain fluorinated, chlorinated, and sulfonated
films, respectively. The main goal of this thesis was to
sulfonate PP films and to study the barrier properties of
the sulfonated films as compared to the non-sulfonated PP.
Sulfonation process which modified the surface properties
did not alter the properties of the bulk polymer, but rather

the surface of the film.

2.1 SULPONATING REAGENT

A sulfonating reagent is a compound which is able to replace
a carbon-bonded hydrogen atom in a polymeric molecule by a
sulfonic group (803) . Sulfur trioxide is a powerful
sulfonation agent.

The sulfur trioxide molecule is planar, triangular, and
symmetrical (Gilbert, 1965). It is a resonance hybrid in
which the oxygen atoms are equivalent. The S-O bond is
unusually short, indicating considerable double bond
character. Although the exact distribution of electrons
between sulfur and oxygen is uncertain, the behavior of SO3

in chemical reactions indicates that the sulfur atom is

7
strongly electron-deficient. At the same time, the oxygen
atoms are electron-rich. The SO3tmolecule has been
described as a "Lewis acid on one side (i.e., the sulfur),
and a Lewis base on the other (oxygen) ." When S03 reacts
with polymer films, the acidic sulfur atom attacks electron—
rich (basic) systems, and the basic oxygen atoms accepts
acidic protons (Gilbert, 1965).
There are three forms of sulfur trioxide, solid, liquid and
gas. Although solid 803 has been used to a minor extent in
the laboratory for making complexes, and for conversion to
SO3 vapor by heating, it has not been considered a
commercially practical compound because of its variability,
difficulty in handling, and the high increase in vapor
pressure occurring during vaporization. Liquid 803‘ could be
stabilized satisfactorily against polymerization to solids
by addition of a small quantity (as low as 0.1 %) of various
compounds - especially derivatives of boron, phosphorus, or
sulfur, - resulted in its commercial introduction. For
laboratory purposes, the use of SO, in liquid form may
involve the freshly distilled, or the stabilized commercial
material. Vaporization of the $03, and dilution with dry air
to about 10% strength, is more commonly used as a standard
laboratory procedure. Vaporized $03 is a much milder reagent
than the pure liquid 803. On a commercial scale, sulfonation

is carried out with liquid SO3 stabilized by mixing it with

8
a solvent, such as liquid SOZ,‘or, more commonly, is in gas
phase mixed with dry air. Vapor 803 is also obtained
commercially by distillation of oleum, from sulfuric acid
plant-converter gas or by burning sulfur to obtain SOzanui
then continuing the oxidation process of SO2 to 803.
The major advantages cited for the use of SO3 are rapid and
complete reaction, with no energy requirement for completing
sulfonation. The major problem is that sulfur trioxide has a
strong affinity for water. Therefore, it is necessary to
find practical procedures for preventing that water get in
and contact with $03 so that the SO3 becomes available to
react with the polymer films. Recent Raman spectral studies
and other studies of sulfonation kinetics indicated that
monomeric $03 is the true reactive species in oleum and
sulfuric acid, as well as in liquid 80 , and that the water
present in the hydrates functions merely as a complex agent

and solvent (Miller, 1986).

2.2 SULFGNATIQN REACTION

It is generally accepted that during sulfonation by either
liquid or gas phase, the hydrogen either in a C-H or N-H
bond is replaced by an SO3 molecule which is then
hydrogenated to form a sulfonic acid at the site of

attachment.

9
Surface sulfonation of polyethylene (PE) with gaseous SO3
was reported by J. Ihata (1988). The structure of the
sulfonated PE films was determined by spectroscopic data
such as IR, UV, and Resonance Raman Spectra. Resonance Raman
Spectra showed three bands characteristic of polyenes
(double bond); IR spectra showed the bands of vs O-S-O and
vas O-S-O, which shifted toward higher wave number by the
growth of polyenes having the adjacent sulfonic acid groups;
UV-VIS reflectance spectra showed both a hyperchromic effect
and a bathochromic shift with increasing polyenes. It was
confirmed that a PE film and SOB gave unsaturated sulfonic
acid and that, as the reaction proceeded, the elimination of
sulfurous acids took place to form sulfonic acids having
highly conjugated C=C unsaturated bond. The reaction

mechanisms is indicated in Figure 2.1.

 

SO
-CHz-CH2-CH2- ———3. —CH2—CH2—CH— ———-. -CH2-CH2 -
: I _
SO3H I so3 H+
——.. -CH2-CH=CH-
‘stos

—CH=CH—CH2-CH— —-’ -CH=CH—CH=CH—

30311

Figure 2.1 Sulfonation Reaction Scheme of PE

10
These findings were also confirmed by J. Tardiff (1993), who
studied diffusion and reaction of sulfonate groups within
the polymer matrix of sulfonated polymeric films. H. Asthans
(1993) studied chemical modification of polymer surfaces
using sulfonation to improve adhesion properties. Asthans
indicated that desulfonation (which results in formation of
H2803) occurs easily in case of polymers containing only
aliphatic carbon as compared to a polymer containing

aromatic carbon.

2.3 Neutralization

The sulfonic acid groups generated during sulfonation can be
neutralized to created a more stable group. Neutralization
can be carried out with a variety of bases, e.g. ammonia gas
(N113) or aqueous ammonium hydroxide (NH,OH) . Neutralization
with ammonium hydroxide will extract the hydrogen from the
sulfonic acid and have a stabilized ion pair (-C-SO{NH[).

The reaction scheme is shown in Figure 2.2.

303'}? sos'NH,+
NH‘OH
—CHZ-CH—CH2 -—-» -CHZ-CH-CH2— + H20

Figure 2.2. Neutralization Reaction Scheme of PE

11
Neutralization can also be accomplished by depositing metal
ions via ion exchange from water solution. Various metal
ions can be used, for example, lithium, sodium, copper,
magnesium, nickel, cobalt, manganese, vanadium, and
strontium. Also the barrier and physical properties of
sulfonated polymers are strongly dependent upon the
counterion utilized. W. Walles (1989) found that Na’ ion was
6 times more effective than NHf’ion in regarding the
diffusion of oxygen through a sulfonated membrane, Idf was
12 times more effective than NHfi} all at a surface

concentration of about 0.7 g S/mz.

2.4 Previous Studies

2.4.1 Reaction of the sulfonation polymer surface

Olsen and Osteras (1969) used fluorescent multiple internal
reflection (FMIR) spectroscopy to obtain direct evidence of
the nature of the surface groups of the sulfonated
polyethylene. J. Ihata (1988) reported on a study of the
photoreaction of polyenesulfonic acids by ESR, where the
desulfonation reaction took place. It was found that
conjugated polyenesulfonic acids formed by the reaction
between PE films and 803 were sensitive to visible and UV
radiation that cleavage the C-S bonds of the sulfonic acid
groups adjacent to polyenes. The resulting polyene radicals

either reacted with oxygen in the air to form ketone

12
compounds or released hydrogen atom to give more conjugated
polyenes on the average under reduced pressure.
Cameron (1985) have proposed that the most significant
chemical changes on the surface is olefinic conjugation
leading ultimately to carbonization. Recently, H. Asthana
(1994) studied on the sulfonated polypropylene and
polystyrene. He found that sulfonation of PP leads to a
mixture of various kinds of compounds besides sulfonic acids
by contact angle and XPSA. There are no signs of degradation
or desulfonation in polystyrene as was seen in
polypropylene.
2.4.2 Effect on Electrical and Physical Properties
C. Fonseca (1985) proposed that the bulk electrical
properties of the inert polymers (as polyethylene) can be
modified by Sulfonation to dope or introduce polar
molecules. From the critical surface tension and platelet
adhesion tests, they also found that the microindentation
hardness and the critical surface tension of this polymer
increased.
N. Inagaki (1987) found that the sulfonation of phenyl
groups in the plasma-polymers occurred rapidly within 1 min
when exposed to $03 gas. The sulfonation made the plasma-
polymer electrically conductive and showed a strong
dependence of the impedance on the relative humidity.

2.4.3 Effect on Mechanical Properties

13
F. Calleja (1984) investigated the surface hardening of
polyethylene through sulfuric acid exposure. He found that
exposure of PE to a sulfuric acid atmosphere substantially
improves the mechanical properties of the thin sulfonated
surface of the polymer, yielding hardness values which are
in the vicinity of some metals. In addition, it is shown
that microindentation hardness proves to be an extremely
sensitive technique which enables a fine detection of the
local surface hardening of polymer, developed at very low
levels of sulfonation.
However, In L. Esbensen (1991) study of the effect of
neutralizing cation of a surface sulfonated polystyrene
film, the tensile properties exhibited no evident
correlation with the valance of the neutralizing cation, nor
with the atomic radii or atomic number of the cation.
2.4.4 Effect on the Barrier Properties
Walles (1973) studied on the resinous enclosure members
(HDPE bottles, LDPE bottles, tank, PP bottle & PVDC bottle)
to rendered impermeable by sulfonation. The sulfonated
enclosure members are rendered substantially impervious to
the penetration of various solvents and vapors by degrees
from about 0.015 to about 50.0 milligrams on a square
centimeter of surface sulfonation. In 1973, Walles reported
on the surface sulfonation-epoxidation of polyethylene and

polystyrene, too. He found that these polymers were rendered

l4
adhesive, antistatic and highly impermeable to oleophilic
materials and low molecular weight gas such as oxygen and
carbon dioxide by initially surface sulfonating these
polymers and subsequently reacting the substitute sulfonic
acid groups with alkylene oxide or similar expoxide to form
the corresponding ester of sulfonic acid. Further, Walles
(1984) studied on the metallized plastic articles.
Metallized plastic article which can optionally be treated
with an additional amount of an aqueous colloidal dispersion
of an organic polymer or metal provides essentially
impermeable to atmospheric gases and other vapors. In
addition, the barrier properties obtained by surface
sulfonation were found strongly dependent upon the nature of
the neutralizing counterion. Walles (1989) found that Na+
ion which substituted NHg'via an ion exchange reaction of a
sulfonated polyethylene film was 6 times as effective as
NHA’ ion with respect to oxygen diffusion through the
sulfonated membrane. Idf was 12 times more effective than
NHA*,.a11 at a surface concentration of about 0.7 g S/mz.
Chiao (1988) investigated on gas separations using membranes
comprising sulfonated polyether sulfone. He found that
sulfonated of polyether sulfones have good separation
factors for oxygen, nitrogen and carbon dioxide methane

separations from a mixture gases.

15
However, Esbensen (1991) reported that exchange of the
neutralizing cation ammonium with the following cations:
Idf, Nafl,IC, mg”, ca” and Ba” had no effect on the barrier
characteristics of the surface sulfonated polystyrene film
for the penetrants, oxygen and water vapor, at the 0.8 pg

S/cmz and 50 A, respectively sulfonation level.

16

PERNEABILITY

3.1 Introduction

The study of the permeability of plastic packaging films of
gases, water vapor and organic vapors is both practically
and theoretically important. Properly design packaging
system can prevent product deterioration by controlling
excessive gain or loss of gases and vapor during product
storage. The permeability P of a film or sheet specimen is

given as following equation:

where: Q = mass or volume rate of permanent gas or vapor.
l a thickness of the film.
t = time
0p a partial pressure differential.
The permeation mechanism actually involves three steps
(i) sorption and solution of the penetrant into the polymer
(ii) diffusion of the penetrant through the polymer matrix

(iii) desorption of the penetrant from the surfaCe of the

polymer.

l7
Diffusion coefficient (D) and permeability (P) values are
obtained from permeability studies, isostatic procedure or
quasi-isostatic procedure.
The basic equations for describing the diffusion process are

Fick's first and second laws of diffusion ( Hernandez,etal,

1986)
dc
F=-D— 2
dx ( )
and
32.1 (,3.ch (B)
t dX' dx
where:
F = the flux or mass of diffusion per unit area per
time
c = the concentration of the penetrant in the film
D = the mutual diffusion coefficient, in (length)3/time;

According to Henry's Law, the concentration of the penetrant
(c) in the polymer and the penetrant concentration in the

gas or vapor phase in the equilibrium with the polymer is:

C=Sp (4)

where:

18
S = the solubility coefficient.

By substituting equation (3) and (4) into equation (1)

P=DS

3.2 Permeability Measurements

A permeability cell consists of two half cells which hold a
film sample tightly. One of the half cell hold the gas or
vapor to be used as the permeant. The permeant diffusing
through the film goes into the other half cell, where is
accumulated or conveyed to a detector measurement. Three
methods can be utilized measuring permeability of a film :
(i) Isostatic Method

(ii) Quasi-isostatic Method

(iii)Absolute Pressure Method

3.2.1 Isostatic Method

In the isostatic method, the total pressure in both chambers
of the permeation cell is constant. This is achieved by
keeping both chambers of the permeation cell at atmospheric
pressure. In the permeability measurement, there must be a
difference in permeant partial pressure across the film. The
permeant at the lower concentration chamber is conveyed to
specific detector by a carrier gas for quantitation.

Isostatic method is commercially available for measuring CO2

19

 

Thus

figure 3.1 mica]. Transmission late Profile Curve for
Isostatic Procedure (Take from Senandes etal)

 

_ Total Ouantlty Pounoatod (0)

 

 

I
0-.-| 11mm

time 3.2 mice]. Transmission late Profile Curve for
Quasi-Isostatio Drooeduse

20
and.C§ permeability of both plastics films and fabricated
packaging articles.A representative transmission rate curve
describing the transport of a permeant through a polymer
membrane in an isostatic method is shown in Figure 3.1.

A First approximate solution to the Fick’s second law is

 

given in Equation (5) ( Hernandez, 1986)
(AM/At)t_ 4 12 1/2 -12
(AM/At)_-(\/—fi)(4Dt) exmwt) (5)

Where:
(OM/0t)t = the transmission rates of the penetrant at time
(t)
(OM/Ot)m = the transmission rates of the penetrant at
steady state.
For each value of (OM/Ot)t/(OM/Ot)m, a value of 13/4Dt can
be calculated, and by plotting (4Dt/l’) as a function time,
a straight line is obtained. From the slope of this graph, D

is calculated by substitution in Equation (6)

D: (slope) 12 (6)

Equation (6) can be derived as following: (Hernandez, 1986)

21

2
D= 1 (7)
7.199%“.

 

where:
tms = half of the time required to reach a rate of
transmission (OM/Ot)m value.
The permeability coefficient (P) can be determined from the

isostatic method by substitution into Equation (8)

==aGfl (8)

P Ab

 

where:

a a calibration factor to convert detector response to
units of mass of permeant/unit of volume
[(mass/volume)/signal units]

G = response units from detector output at steady state
(signal units) 4

f = flow rate of sweep gas conveying penetrant to detector
(volume/time)

A = area of the film exposed to permeant in the
permeability cell (area units)

b a driving force given by the concentration or partial
pressure gradient (pressure or concentration units)

3.2.2 Quasi-Isostatic Method

22
The quasi-isostatic method is different from the isostatic
method of measuring permeability. In this case, the lower
concentrated chambers is completely closed as it collects
the permeant. However, the difference in penetrant partial
pressure or a concentration gradient between the two
chambers must be maintained constantly. The concentration of
permeant gas or vapor that has permeated through into lower
concentration chamber can be quantified by gas
chromatography, using a sampling syringe.
In this method, the permeated gas or vapor is accumulated
and monitored as a function of time. A generalized
transmission rate profile curve describing the transport of
a permeant through a polymer membrane by the quasi-isostatic
method is shown in Figure 3.2.
The diffusion coefficient can be calculated as following (

Hernandez, 1986).

H
N

(9)

U
u
8|

Where:
8 = the intersection of the projection of the steady-
state portion of the transmission curve (see

figure 5), called the lag time.

23
The steady state permeability coefficient (P) can be
determined from the quasi-isostatic method by substitution

into Equation (10)

(10)

'fi’
6|:

where:

y = the slope of the straight line portion of the

transmission rate curve (mass/time)

3.2.3 Absolute Pressure Method
With the absolute pressure method, the sample is mounted in
a gas transmission cell forming a sealed semi—barrier
between two chambers. One chamber contains the test gas at a
specific high pressure and the other chamber, at lower
pressure, receives the permeating gas. There are two
methods:
1. Pressure Differential Method

2. Volume Differential Method

MATERIALS AND METHODS

SULFONATION

4.1 Materials
Film.Sample
Oriented Polypropylene (OPP)
2 mil biaxially oriented polypropylene film, provided by
Mobil Company, was used in these studies. The level of
orientation was 420 % (machine direction) and 800 % (cross
direction), based on the initial film dimensions. The

percent crystallinity was 45.7 6.
Sulfonating Agent

Oleum (HZSZO7) , also called fuming sulfonic acid, was the
sulfonation agent. Oleum was prepared by mixing 100%
sulfuric acid with free sulfur trioxide. The concentration
of oleum we used was 30% (wt/wt). Therefore, a 100 gram
sample of 30% oleum consisted of 70 grams of sulfuric acid
and 30 grams of free sulfur trioxide.

Cleaning Agent

Before sulfonation, the films were cleaned with a
laboratory grade liquid detergent, called Microm,

obtained from Cole-Parmer Instrument Company. The

concentration of Micro'm used in cleaning was 2% (v/v).

Neutralizing Agent

24

25
After sulfonation, films were neutralized with solution of
5% Ammonium Hydroxide in water. Films were immersed in the
DHQOH solution for 5 min.
Salt Solution
Sodium Chloride, Analytical Reagent, obtained from
Mallinckrodt, Inc. (Tray, Michigan) was used to make 5%
salt solution for ion exchanged with NHJZ
water
Deionized water was used to prepare the solution and
wash the films.
Nitrogen Gas
99% nitrogen gas was used as carrier gas supplied by AGA
Gas, Inc. (Cleveland, OH). It was connected to a desiccant

filter with the outlet tube to dry the N2 gas.

4.2 Sulfonation Unit

A schematic of the sulfonation unit is shown in Figure 4.1
(Erickson, 1993). The system is to produce a controllable
gaseous mixture of sulfur trioxide in nitrogen. As it can be
seen, there are four main components : a reactor, a internal
gas circulation loop, a external gas circulation loop and
oleum storage containers. The process to product sulfur

trioxide is as following:

26

s
3
3
2
i
z
a
3

 

Figure 4.1: Schematic Diagram of Sulfonation System
( E. Erickson, 1993)

27

 

Oleum at storage tank

I

reactor

1

140 micron filter

glass saddles of reactor

L

vapor filter tank
(excess vapor droplets)

l

sulfonating chamber

1

Surge tank
(any liquid & solid contaminate)

[

reactor

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 4.2 2 Schematic of the process to generate sulfur
trioxide

4.3 Experimental Procedure

The sulfonation process was performed at the Composite
Materials and Structures Center (CMSC), MSU. All the
polymers in the present work were sulfonated using the same
experimental protocol which included cleaning, sulfonating
and neutralizing steps. The independent variety used was

time exposure. Temperature was kept constant at 23¢1°C.

28
4.3.1 Cleaning Procedure
Prior to any surface treatment, the polymer surfaces were
cleaned to remove any contaminants such as residual mold
release agents, organic from material handling, and other
contaminates.
All of the polymer samples measured 31.75 cm x 15.25 cm and

'm solution, using Lint-Free

cleaned with a 2% Micro
disposable laboratory tissues. After this, they were washed
by deionized water. The films were hanged to dry by air at
room temperature.

4.3.2 Sulfonation Procedure

Clean, dry film samples were mounted on a metal rack and
placed in the sulfonating chamber equipped with an inlet
tube for gaseous $03, an inlet tube for N2 gas and an
exhaust tube. The chamber was then closed using C-clamps to
form a vacuum tight seal with the chamber.

Nitrogen gas was flowed at a rate of 32 1/min for 3 min into
the sulfonating chamber to replace the air inside. Stopped
purging nitrogen gas and vacuum the chamber for 10 min that
inner pressure was reduced to about 300 um Hg, followed by
another 3 min purge nitrogen gas at the same flow rate in
order to reach atmosphere pressure and replace dry N2 gas.
This process was intended to eliminate air, water vapor and

any active gas thatmay react with SO3 gas and interfere

with the sulfonation reaction.

29
Sulfur trioxide gas was circulated through the sulfonating
chamber to surface react with the films during the selected
time intervals of 1, 2, 3 minutes. The sulfur trioxide gas
was generated in the sulfonation unit and transferred to the
sulfonating chamber via the external circulation lines. The
temperature was adjusted at 32:1°C to obtain the desired
concentration about 1% (v/v) $03..A gas sample was taken
during each running from sulfonating chamber to determine
the Ph in order to measure the concentration of the sulfur
trioxide in the chamber. The $03 concentration was

determined by the following expression ( Erickson, 1993).

Y=209 .9436*(exp[-2.0649 (pH) 1) (11)

Where : Y

803 Percentage (v/v)

Ph the value of the acid which was generated by SO3
reacted with water.

After a period of sulfonating time, the SO3 gas tube was
closed and a purge of N2 gas at a rate of 32 liter per
minute was flown for 5 minutes to remove SO3 gas before the
chamber was opened. This was done to avoid releasing SO3 gas
into the working area.

4.3.3 Neutralization Procedure

After sulfonation, the polymer films were immediately

removed from the sulfonating chamber and neutralized by

3O
dipping in a bath containing 5 % aqueous ammonium hydroxide
in water. The films were kept in the bath for 5 minutes. The
films were then washed using deionized water and air dried
at room temperature. This process yielded a ammonium cation
neutralized sulfonated PP films.
4.3.4. Ion Exchanging Procedure
The NHi'cation in the sulfonated PP films were replaced by
Na’ cation by immersing in 5% NaCl aqueous solutions for 3
hours. The films were then removed from the NaCl solutions
and washed with deionized water to remove the excess of NaCl
from the surface of the films. The films were dried by air
for 24 hours. Before doing permeation studies, the films
were put into vacuum chamber to remove most of the moisture

from the films for 8 hours.

PERMEABILITY MEASUREMENT

The sulfonated film samples were evaluated in terms of the
surface composition, oxygen permeability, carbon dioxide
permeability, and water vapor transmission rate, then were

compared to the non-treated films.

5.1 Electron Spectroscopy for Chemical Analysis (ESCA)

All the film samples were analyzed by X—ray Photoelectron
Spectroscopy or Electron Spectroscopy for Chemical Analysis
(ESCA). The analysis was performed by Dan Hook on a Perkin
Elmer 5400 XPS at Composite Materials and Structures Center,
MSU. This analysis determined the surface compositions of
the films up to a depth of 50 angstrom. Each composition is

reported as atomic percentage.

5.2 Oxygen Permeability Measurement

Oxygen permeability studies were performed using a MoCon Ox-
Tran 100 Permeability Tester (Minneapolis, MN). (figure
5.1). In order to control the water activity of the carrier
gas (N5) and Oxygen gas, a device was built attach to mix
the dry gas with 100% wet gas (see figure 5.2). It was
connected between the gas tanks and MoCon Oxtran 100. This

device allowed the two streams, C5 and carrier gas (N5), to

31

32

 

 

 

 

o
spec/an! (; run “I!
\‘\\\ ‘ \\.\"\‘\“‘_ \. ‘.
\‘ \x \
amuse
a“
scram-r?"

 

 

 

 

“can. t

-r

I‘ OIUW"

 

a.“
'1

 

'1

 

 

 

Figure 5.1: Schematic Diagram of Oxygen Permeability Test
System (MoCon Inc.)

Washing Bottle

 

 

 

 

 

 

 

Oxygen
v Sensor
Washing Bottle
Nitrogen
figure 5.2: Schematic Diagram of Water Activity Control

System

33
be adjusted to selected water vapor activity, by operating
the flow of the wet and dry gas stream. Water vapor
activities of each gas were measured using a hygrometer
sensor from Hydrodynamics Inc. (Sliver Spring, M0) (N0. 45-
100-15). The relative humidity of each temperature was
determined by using humidity calibration curve (see Appendix
A) supplied by Hydrodynamics Inc.
The testing procedure for measuring oxygen transmission
rates was based on the "Standard Method of Test for Oxygen
Gas Transmission Rate through Plastic Film and Sheet Using
Colometric Sensor", according to the ASTM D-3985. The 02
permeability of two film replicates were determined at 3
different temperatures ( 13°C, 25°C, and 35°C) at 0% RH and
70% RH. The reported value was obtained by averaging the

values obtained on each of the two replicates.

5.3 Carbon Dioxide Transmission Rate

(XL transmission rate was measured by using MoCon Permatran
C-IV built by MoCon Inc. (Minneapolis, MN). The procedure
recommended by the instrument manual was followed. The CO2
transmission rates of film samples were determined at 23°C
and 0% RH.

5.4 water vapor Transmission Rate

A Permatran W from MoCon Inc. (Minneapolis, MN) was employed

to measure the WVTR of each samples at 3 different

34
temperatures (27°C, 33°C, 37.8°C). The test procedures for

Conventional Flat Barrier Materials was followed

35

ZDXFJULWNZCOJ-

Er-
t 1

 

 

VALVE-

—" ”when...

 

 

 

 

' de
Pi e 5.3: Schematic Diagram of Carbon Dioxi
S“! Permeability Test Syst- (MoCon Inc.)

 

 

 

 

 

 

 

Pigure 5.4: Schematic Diagram of Water Vapor
Permeability Test System (MoCon Inc.)

RESULTS AND DISCUSSION

6.1 Sulfonation

6.1.1 Quantitative Chemical Analysis by ESCA

The surface composition of the untreated polypropylene film
and the sulfonated polypropylene sample films were
determined by Electron Spectroscopy for Chemical Analysis
(ESCA). The results are presented in Table 6.1 and 6.2.
These results are also presented graphically in Figure 6.1
and 6.2.

Table 6.1 : Percent atomic composition for polypropylene

sulfonated from O to 3 minutes as obtained by ESCA on the

 

 

 

 

 

 

 

 

surface.
Sflfomfifion Carbon Oxygen Nitrogen Sulfur
T‘me . (atom %) (atom %) (atom %) (atom %)
(m1n)
0 93.1 6.9 0 0
1 63.60 24.05 3.07 4.14
2-a 61.76 25.09 3.40 5.20
2-b 58.0 28.90 6.60 6.50
3-a 61.28 24.79 4.04 4.20
3-b 62.13 26.07 5.06 6.74
3-c 65.42 22.88 4.91 6.79

 

 

 

 

 

 

 

36

Table 6.2 : Relative Atomic ratios of Sulfonated PP films on

the surface

37

 

 

 

 

 

 

 

 

 

 

 

 

Sulfonation C/S N/S S/C
Time (atom/atom) (atom/atom) (percent
(min) atom /atom)
O _ _ _
l 15.36 0.74 6.51
2-a 11.88 0.65 8.42
2- 11.20 1.01 8.93
3- 14.59 0.96 6.85
3- 9.22 0.75 10.85
3- 9.63 0.72 10.68

 

 

Table 6.1 are the atomic concentrations for carbon, oxygen,
nitrogen, and sulfur determined as a function of sulfonation
for each 100

time. This table indicates that, for example,

atoms, 63.6 are carbon atoms for a sulfonation time of 1
minute. The oxygen detected in the non-sulfonated film can

be attributed to a small oxidation process by air, perhaps

during corona treatment. The following comments can be made
from the data in the tables.

1. The larger change in atomic compositions takes place at

the first minute. This indicates that a rapid chemical

reaction takes place when SO3 contact the film.

38
2. The sulfur concentration increases as the treatment time
increased. Asthana (1993) investigated the sulfonation of PP
film at 4 minutes and 5 minutes and found that there was a
maximum amount of sulfonation that could be carried out
without extensively damaging the surface. According to his
data, the maximum degree of sulfonation that can be achieved
without damaging the surface of PP is one 803 group per
three repeat monomer units of PP, in other words that the
ratio of carbon and sulfur is around 9. The similar results
can be seen in Table 6.2 and Figure 6.1 at 3 min sulfonated
PP film. C/S is about 9. Compared the percentage of 8 atomic
on the surface, it increased rapidly from 0 min to 2 min
sulfonation and increased slowly from 2 min to 3 min
sulfonation. It can be concluded that increasing the
sulfonation time can increase the sulfonation level on the
surface of the polymer before achieving a saturation value.
The saturation sulfonation value on PP film surface in this
study is reached at 3 minutes treatment.
3. Concentration of the sulfur on the surface in 3-a sample
was very low compared with the other two samples which were
at same treatment time. The result may be caused by
following reason.
a. Eventual surface contamination

b. Variation of sulfur trioxide vapor concentration

5% atom on the surface

39

 

 

 

 

8
7'- D
D
6-
D
5-
D

4- o
3(-
2..
‘-
o t 1 l l J l

o 1 2 Z 3 3

Sulfonation tine (mlmte)

Figure 62.1: Sulfur concentration on the PP film
surface as a function of sulfonation time

chCI‘l‘l‘il‘ ll

 

4O

20

15—

 

 

5 1. /
. /'
f //
O 1 2' 3 4

Sulfonation Time (minute)

-- pert-its. at. (els) of sulfu- ch the Mace of the eulfemtee PP (In!)
-- PM- as!” of eutfur of the malfemtes PP (I. “New”, 1”!)
-- m eelfit chemo of the mtfemtes PP (4. Tent", 1903)

m It!“ d St W! D.

Pigure 6.2: Percentage weight of sulfur on the surface of
the sulfonated PP, of the sulfonated PP. and percentage
weight change of the sulfonated PP vs sulfonation tine.

41
6.1.2 SO3 Gas Reacting and Diffusion with Polypropylene
It was observed that starting as a transparent film, the
sulfonated PP was dark brown after sulfonation. This
observation was also made by J. Ihata when polyethylene
samples were sulfonated. The presence of the conjugated bond
in the polymer backbone for sulfonated polyethylene and
polypropylene have also been supported by FT-IR experiments,
as indicated in page 9. With longer reaction times, the
color of PP film will be darker and a layer of the dark
sulfonated film will eventually slough off after rinsed with
water. This indicates that the strong degradation processed
that the polymer film surface was sulfonated. The film
surfaces became light pale green within one minute of the
sulfonation changing to yellowish and later to dark brown as
the sulfonation processed. Two degradation process may take
place during sulfonation. One process involves oxygen from
air to form ketone compounds, the other mechanism removes
hydrogen atom to give conjugated polyenes. Figure 6.3
illustrates the formation of conjugated double bonds in the

polymer chain as a result of sulfonation.

42

CH3 CH3 CH3 CH3 CH3
so3 | 412503 | +1280, | |
—CH—CHf--——————+ —C—CH{—-——————+ —C=CH- ——————+—C=CH-C-CHf-

Hso3 Hso3

Figure 6.3 : Sulfonation reaction scheme of polypropylene
ESCA analysis indicates that the percent sulfur at the 3 min
sulfonated PP film surface reached a maximum value. However,
the total weight percent sulfur in the whole sample,
determined by Wangwiwatsilp, 1993, increased linearly with
sulfonation time. This indicates them that $03 gas diffused
into the film and continued reacting with PP beyond the
surface. This result is supported by the linear relationship
of mass uptake in PP versus sulfonation time reported by J.
Tardiff (1993). In Tardiff’s study, polystyrene and
polypropylene films were sulfonated while using a quartz
spring balance to measure the weight gain as a functional
time. In her experiment at 20°C sulfonation temperature, the
percent mass uptake for polypropylene was 85% after 8 min (
PS was 6.44%). Unlikely that such a high mass uptake is due
strictly to the diffusion $03 and the reaction to form
sulfonated polymer. It appears that sulfurous acid formed by
the side reaction condenses on the film to produce the large
weight gain. The reaction mechanism of sulfonation in

polypropylene is much more complicated than originally

43
expected. On the other hand, the weight gain in polystyrene
appears to have reached a steady state value. Therefore, the
concentration of SO3 at the interface can be determined by

the following equation with great confidence (J. Tardiff,

1993).
dC
D=—=De °C 12
dt: °xp ( )
where:
Do = the diffusion coefficient in the limit of zero
concentration
a = a variable determined empirically
C = Concentration of the $03 in the sulfonated polymer.

For Polypropylene, the relation between the sulfur weight
gain within the polymer film as a function of sulfonation
time is linear and did not reach steady state model at the
end of the experimental run. Although the diffusion
coefficient and depth of the reaction within the film bulk
phase can not be calculated by exact number using Equation
(12), it can be calculated as following under the assumption

that the sulfonation layers are homogenous.

11=%x2"115x13 (13>

 

44

where : A% the sulfur concentration on the surface

B% the sulfur concentration of the total film
ls is the depth of the sulfur determined by ESCA
l = the thickness of the film
11 is the depth of the sulfonation of the film
The results of sulfonation depth are presented in Table 6.3.

Table 6.3: Depth of the sulfonation of the sulfonated PP
films at different sulfonation time.

 

 

 

 

 

 

Sulfonation Percentage of the Depth of the
Time (min) sulfur atom on the sulfonation
surface (cm) .
O o o i
1 4.14 1.6 x 10'5
2 5.20 3.1 x 10'5
3 6.74 4.0 x 10'5

 

It can be concluded as following:

1. In figure 6.2, as expected, the concentration of the
sulfur on the surface of the film is the highest, followed
by the weight changed of the film. The sulfur percentage of
the total film is smallest. The sulfonation reaction
happened at the surface of the films.

2. In Table 6.3, the depth of the sulfonation increased with

increasing the treatment time.

45
6.2 Oxygen Permeation Study
6.2.1 Film neutralized with NH['
The isostatic method was employed to determined oxygen
permeability. Oxygen permeability studies were carried out
with air at a flow rate of 25 cc/min, at different
temperatures, and a water vapor activity of a=0 and at 26°C
with a=0.7. Oxygen permeability were measured at 0% RH on
film samples sulfonated for 1, 2, 3 minutes and blank
samples. Results of these measurements at 13°C, 26°C, and
35°C are presented in Table 6.4 and Figure 6.4. Oxygen
permeability as a function of sulfonation time is presented
in Table 6.5 in which the activation energies included. Data
from Table 6.5 is graphed in Figure 6.5. From these results,
it can be seen that oxygen permeability at 0% RH was reduced
as the sulfonation time increased. As expected, the oxygen
permeability of sulfonated PP films decreased as the
temperature decreased. The activation energy of the oxygen
permeability for all samples of sulfonated PP was the same
as for the untreated PP films. As indicated above, the
sulfonation on the surface was not the same for all the
samples. For example, 8% atom on the surface of the three 3
min sulfonation PP films are 4.2 % 6.74 %, and 6.79%,
respectively. This difference in atomic sulfur was reflected
in the oxygen permeability value. The lower the percent of

atomic of sulfur on the surface, the higher oxygen

46

Table 6.4: 02 permeability of sulfonated PP with 0% RH at

13°C, 26°C. and 35°C neutralized with NH".

   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Temp. suiixatw 3:26;"; (£32,331? .3)! 3m)
(min) thePP
#1 #2 Average
13°C mtrelted O 1007 998 1002
l 4.14 910 872 891
2 5.2 726 717 722
3-a 4.2 700 705 702
3-b 6.74 436 436 436
26°C mum-d 0 2315 2363 2339
1 4.14 2228 2228 2228
2-a 5.2 1932 1937 1935
2-b 6.5 1840 1840 1840
3-a 4.2 1695 1700 1697
3-b 6.74 920 954 937
35°C mtmtcd 0 3666 3734 3700
1 4.14 3351 3414 3382‘
2 5.2 2673 2721 2697
3-a 4.2 2688 2707 2697
3 b 6. 1564

 

 

 

 

 

47

 

 

 

 

Figure 6.4 8

SEE
(
,eee
.
‘F
.
(P
.
1)
.
-— - —— .p ---—P
.
1P
0
J.
'
o
.
y———-- - — -—-df
.
{D
‘P
o
C
a
C
3 3 3 3 3 3 9 3 °
-
WWW»

4.14 5.2 15 4.2 0.74

4.2 0.74

5.2
3*“ 1* 2H! 3H!

4.“

4.2 0.74

5.2
met-s. 2m 3w

4.!4

3'6

an
stuns-mm '

“'0

Oz permeability of sulfonated PP at l3'c, 26°C
and are with our (nag)

Table 6.5:

function of sulfonation degree of PP.

48

Activation energy of the oxygen permeability as a

 

 

 

 

“2:12;”
(KJ/ml)
n... 13°C 35°C
111 m 0.00350 0.00335 0.00325
axon unmet-a 3.00104 3.36902 3.56816 2266 10354
:6. 4.14 2.94969 3.34783 3.52924 2325 10626_L1
surface 5.2 2.85826 3.26465 3.43092 2305 10535
of m 4.20 2.64644 3.22976 3.43092 2337 10680
N- 6.74 2.63931 3 3.19427

   

 

 

 

 

 

 

 

.00333

 

 

 

 

49

3. ‘
gésséllm!
,...a.|||||?

 

v

 

 

 

 

Figure 6.5: Activation energy of the oxygen-permeability
as a function of sulfonation degree of PP

50
permeability. But the oxygen permeability was not only
affected by the surface concentration S, it also by the
sulfonation time with the same S concentration value. For
example, the permeability of the sample sulfonated for 3
minutes with 4.2% S at the surface was lower than the 1 min
sulfonation sample with 4.14% S at the surface. The reasons
will be discussed in the diffusion coefficient & solubility
studies.
Calculation of Diffusion Coefficient
The diffusion coefficient (D) was calculated from the
unsteady state fraction of the oxygen transmission rate
data. The calculation procedure follows the procedure
described by R.Hernandez (1986).

Equation (5) was rewritten as:

A=X1/2 exp ( -X) (14)

where

gfl (AM/At) c

A 4 (AM/At).

 

= 12 (15)
X 40::

 

The equation can be rewritten as

51

G=X1/2 exp (-X) -A (16)

with G being equal to zero, to satisfy Equation (14). The

iteration process is described by

G(k)
X’k 1 =X'k -
< + ) ( ) exp{—X(k)}{1/2[X(k)11/2-LX(k)11/2} ”7’

 

where (k) is one iteration step.

Here, a basic program (see Appendix B) was written based on
equation (17) using for calculating the oxygen diffusion
coefficient of PP films. The results of oxygen diffusion
coefficient of sulfonated PP at 13°C, 26°C, and 35°C with 0%
RH neutralized by NHf'are summarized in Table 6.6 and
presented graphically in Figure 6.6. As expected, the oxygen
diffusion coefficient of sulfonated PP decreased with
decreasing temperature. No change was found on the diffusion
coefficient as a function of sulfur content.
An apparent oxygen solubility was calculated by Equation (4)
The results of oxygen solubility at 13°C, 26°C and 35°C with
0% RH neutralized by NHf'are listed in Table 6.7 and
presented graphically in Figure 6.7. The solubility of PP is
affected by concentration of the SO3NH6+ on the sulfonation.

The higher the 8% atomic on the surface, the lower the

52

Table 6.6: Diffusion Coefficient of sulfonated PP at 13°C,

26°C and 35°C with 0% RH neutralized with NHf’

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

 

 

   

==-==—--=====-—-—=-=:ma---—=—=-===-—-—-—-—-—-—-—-—n
Temp suffix“: 23.33.33: 02 Diffusion Coefficient
(min) the film (cm/sec.)
#1 #2 Average
13°C untreated 0 1.06 1.05 1.05
1 4.14 1.05 1.00 1.02
2 5.2 1. 1.07 1.06
3—a 4.2 1. 1.08 1.04
3-b 6.74 1. 1.00 1.01
26°C tantra-ted 0 1. 1.25 1.24
1 4.14 1. 1.35 1.26
2-a 5.2 1. 1.41 1.39
Zjb 6.5 1. 1.43 1.42
3-a 4.2 ' 1. 1.18 1.17
3-b 6.74 1. 1.25 1.21
35°C (MN-“6 0 1. 1.30 1.25
1 1. 1.24 1.23
1. 1.42 1.46
1. 1.49 1.37
1. 1.45 1.46

  

 

   
  
  
  
  
  
  
  
  
  
  
  
  
  
    

53

3":

0.8 0.8 0.0.
inn 530 in i. In. in in 'N in i. I. in In in i. I.
z o N v N m 3.? 6 Q5. Nd Dd N25. 3.? o z.“ NT «.0 3.? 0
w . p u r a u u u 0.0

’ D b

1 1‘ 4 ‘

 

1 1 A

7:.

:30

 

Source
at 195..." e

. 1:.

.: Z

A v.-

 

.d m
_ _
_

. _-
. .
_ _
. ._
_ .
. _
_ .
_ _
_ _

 

 

 

’)

26°C and 33°C with our (

diffusion coefficient of sulfonated PP at

o
13°c,

Figure 6.6:

54

Table 6.7: 02 Solubility of Sulfonated PP at 13°C. 26°C, and

35°C with 0% RH neutralized with NHf'

 

 

 

 

 

 

 

 

 

 

 

 

  
  
  
  
  
  
   

  
  
  
  
  
  
  

 

 

    

 

 

 

 

—.——_
W “(2.2% 8.21:"; -o mm
(min, the m,“ (cc 02/ cc Polymer)
#1 #2 Average
13°C untreated 0 0.28 0.28 0.28
l 4.14 0.26 0.26 0.26
2 5.2 0.20 0.20 0.20
3-a 4.2 0.19 0.20 0.20 -
3—b 6.74 0.13 0.13 0.13 h
26°C Winn“ 0 0.55 0.56 0.55
1 4.14 0.50 0.54 0.52
2-a 5.2 0.42 0.41 0.41
2-b 6.5 0.39 0.36 0.38
3-a 4.2 0. 0.43 0.43
3-b 6.74 0. 0.28 0.25
“MN-“6 0 . 0 . 92 0 . 87
0. 0.83 0.81
0. 0.56 0.55
0. 0.54 0.59
0. 0.32 0.32

 

 

 

 

 

 

    

   

 

55

 

 

e
e

04‘. 9' g
in '0 'N '- l '0 '0 in in i. N '0 E0 '0 'a l
3. 0 «e «a :0 O 0.0 NC a a :0 I Q... N. "I 3.0 O

’ p P ’ ’
( i ‘

 

D P I p
f 1 ( i

i P

3 )1

.4
.-
r u ..
.
..
.
_
.
_

Elle
«ass-nae

,3.)an

 

m a

P)
4“
.

m

. L

 

k 13°C. 26°C

’)

ty of sulfonated PP a
at 0%“ (

solubili

and 352C

0

 

 

Figure 6.7:

56
apparent oxygen solubility. The longer the sulfonation time,
the lower the apparent oxygen solubility, too. The same as
oxygen permeability pointed at page 50 that even at same
percent S on the film surface (3 min sulfonated PP film with
4.2% S and 1 min sulfonated PP film with 4.14% S), the
oxygen solubility decreased as increasing sulfonation time.
It appears that an increase surface energy and polarity of
the surface created by the sulfonic groups reduces the
oxygen solubility.
All the measurements and calculation above were based on the
2 mil PP films. Since the sulfonation only happened on the
surface of the PP film. To determine the barrier properties
of the sulfonation layer will help us full understand the
sulfonation to contribution to the oxygen barrier
properties. There are 3 layers in the sulfonated PP films:
sulfonated PP surface/PP/sulfonated PP. The permeability of
the sulfonated PP surface layer can be calculated as

following:

i=2x£+£
P Pl P2

22:11

 

(18)

 

57

Where : 11 is the thickness of untreated PP layer

P1 is the oxygen permeability of the untreated pp

layer

P2 is the oxygen permeability of the sulfonated PP

surface . a
Assume that oxygen solubility of the sulfonated PP surface
is the same as that of total sulfonated PP film. The

diffusion coefficient can be calculated as following:

 

ol=_ (19)

Where D1 = diffusion coefficient of the sulfonated PP
surface.

The oxygen permeability and diffusion coefficient of the

sulfonated PP surface layer are presented in Table 6.8

Table 6.8: Oxygen permeability and diffusion coefficient of
the sulfonation layer of the sulfonation PP filmm

         
   
 
 
  
  
   
   

 

 

 

 

_
sulfonation percentage Oxygen Oxygen Oxygen
tine sulfur atom Permeability diffusion Solubility
(ei n) on the coefficient
smfixm
0 0 2339 1.24 0.55
1 4.14 248 0.14 0.52
2 5.20 129 0.09
3 0.03

 

 

 

 

 

The oxygen permeability and diffusion coefficient of the

sulfonated PP surface are dramatically decreased compared

58
with unsulfonated PP film under the assumption. while
increased the sulfonation time, the oxygen permeability and
diffusion coefficient decreased.
Values of the oxygen permeability, diffusion coefficient and
solubility at 26°C and 70%RH neutralized with NHJ'are E‘
summarized in Tables 6.9, 6.10, and 6.11, respectively.

These values are also presented graphically in Figure 6.8,

 

6.9, and 6.10, respectively, together with values obtained h
at 0% RH. It is clearly shown that the oxygen permeability V
of sulfonated PP at 70% RH decreased a little compared with

the significant changed at 0%RH as well as solubility. The

diffusion coefficient with 2 min or less than 2 min

sulfonated PP at 70% RH were almost same as those at 0%RH.

The diffusion coefficient with 3 min sulfonated PP films

increased at 70% RH. It indicates that sulfonated PP films

are moisture sensitive and loss their barrier property when

present in a moisture circumstance.

Sulfonation PP ion neutralized with ua*

The oxygen permeation for this studies was carried out at

13°, 26°, and 35° with 0% RH. The results of oxygen

permeability, diffusion coefficient & solubility are in

Table 6.12, 6.13 and 6.14 and presented graphically in

Figure 6.11, 6.12 and 6.13, which are provided for

comparison with sulfonated PP neutralized by NH:} The

oxygen permeability of the sulfonated PP with Na+ decreased

 

59

Table 5,9: 02 permeability of sulfonated PP at 26°C at 70%RH

and neutralized with NH".

 

 

 

 

 

 

 

 

Table 6.10:0z Diffusion Coefficient of sulfonated PP at .

 

 

 

 

70%RH neutralized by NH“.

Sulfonated 5% on the 0 Permeability
((1):) :23? °f (cc.mil/m’.day.atm)
#1 #2 Average

untreated 0 2370 2412 2391
1 4.14 2237 2228 2232
2-a 5.20 2266 7 2203 2235
2-b 6.50 2179 2174 2177
3-a 4.20 2169 2189 2179
3-b 6.74 1956 1981 1968

 

 

 

 

 

 

 

 

 

 

 

 

 

“33““ Etc-32;"; 02 Diffusion Coefficient
(min) the file (”'["°')
#1 #2 Average
Untreated 0 1.25 1.26 1.26
1 4.14 1.26 1.27 1.27
2-a 5.2 1.29 1.41 1.35
2-b 6.5 1.37 1.30 1.34
3-a 4.2 1.39 1.38 1.38 .
3-b 6.74 1.34 1.27 1.31 I

 

 

60

Table 6.11:C§ Solubility of Sulfonated PP at 26°C . 70 %RH

neutralized with NHfi'

      
   
   
    
   
  
   
 

 

 

 

 

 

 

 

   

 

    

   

 

 

“:22“ 23.22;"; “2205712133....
(min) the film 2
#1 #2 Average
Untreated 0 0.56 0.56 0.56
1 4.14 0.52 0.52 0.52
2-a 5.2 0.52 0.46 0.49
L 2-b 6.5 0.47 0.49 0.48
H -a 4.20 0.46 0.46 0.46
b 6. 0.43 0.46 0.

 

 

   

61

 

05-min. H t
awn
aAv-no-

 

I
are

sum

I
4.2

 

.
0.5
2*
men
F

0
82
2am

I
4.14
i w

I
P
0.74 e
3‘ mm m
Shea-“

I
0.2 as 42
2d 2*
cum

I
4.14
i d

A L

‘ A
v v

"MW”

 

 

 

Pigure 6.8: Comparison of Oz permeability of sulfonated
n at are with out and 70m (n3)

 

62

_

Minute
«ego
.seae'me

 

’)

 

 

 

 

v.—

 

 

eolalslsele e.
(
raft 5.: o
£3~cr~f~e§aeeaissenseuluus§le t
:6 N. no as v; o v: «e no «a to o a
. l. a L. . a ti i u 9 ed 4.0
a ..
i
f
em
_ .23 a
.m
_ I a0
. i
n ma
3
an.
. 16
D n 02
w . .n ....
. . . .. a»
u
:u
m
Cf
mm
6
W
P

63

 

on; i
est-yen
sew -_

 

I
. I
0 4.14 52 05 4.2 6.14
1 fl 2* 2* 3 n 1"
m RH

. I
O
5.2 OS 41 are
sum 2‘ 8‘ u 1“
semi

!

 

 

 

: 3 3 3 2 8 °
- mama-imp

Pigure6.1os Comparison of O solubility of the sulfonated
PP at 26°C with 0th! and 70m ill.)

64
as the sulfonation time increased. Compared with the
sulfonated PP with NHg'and.Nafiat same sulfonation time, the
permeability of sulfonated PP with N87 is higher than
that of sulfonated PP with NHffl At the same sulfonation
time, the diffusion coefficient of sulfonated PP with Na* is
much lower than that of sulfonated PP with NHffl The
solubility of sulfonated PP with Na’is much higher than
that of sulfonated PP with NHiZ It is found that Na*:ux1
which substituted NHf'via an ion exchange reaction of a
sulfonated PP film could decrease the diffusion coefficient,
but increase the oxygen solubility. Compared the 2 min with
3 min sulfonation PP ion exchanged by Naf, oxygen
permeability of 2 min sulfonated PP film is higher than that
of 3 min sulfonated PP film with similar concentration of
so; on the surface. It is confirmed that increasing
sulfonation time, the chemical reaction take place under the
surface of the film and contribute to film barrier

characteristic.

6.4 COz permeability studies.

(I5 permeability studies were carried out in Permeatran C-IV
apparatus at constant dry CO2 gas flow rate of 80 cc/min and
15 as carrier gas with a flow rate of 250 cc/min, at 25°.
The results of CO2 permeability studies of each film sample

at 25°C are presented in Table 6.15. There values are

Table 6.12: OZ Permeability of the sulfonated PP ion exchanged

65

 

 

 

 

 

 

 

 

 

 

 

 

 

. 7

 

 

 

 

by Na+ at 13°C, 26°C and 35°C with 0 %RH
Tenn. 50: mated firgzcihgf «2.1113233: 31’ i Km)
(min) the pp '
#1 #2 Average
13°C Ultra!“ 0 1007 998 1002
2 6.58 881 906 893
3 6.97 625 630 627
26°C mtreeted 0 2315 2363 2339
2 6.58 2048 2082 2065
3 6.97 1501 1453 1477
35°C "firm-6 0 3666 3734 3700
2 6.58 3588 3632 3610
3 6.97 2475 2518 2496

 

Table 6.13: oz Diffusion Coefficient of sulfonated 99 ion

' exchanged by Na’ at 13°C, 26°C and 35°C with 0 %RH

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ten. Sulfonated 8% on the
1.17:. am: °’ °i3a‘713.§°'""""
#1 #2 Average—
13°C “MIR“! 0 1.06 1.05 1.05
2 6.58 0.95 0.96 0.96
3 6.97 0.72 0.75 0.73
26°C Wflfl" 0 1.24 1.25 1.24
2 6.58 1.15 1.13 1.14
3 6.97 1.04 0.93 0.99
35°C Ufltffltd 0 1.21 1.30 1.25
2 6.58 1.16 1.17 1.17..
1. 1.10 1.08

 

 

 

 

 

 

 

66

Table 6.14: OZ Solubility of sulfonated PP ion exchanged by Na’

at 13°C. 26°C, and 35°C with 0%RH

 

 

fir,
a

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

reap. Sulfonated 5% on the 0 Solubility
mg) firm..." (cc 02/ cc polymer)
#1 #2 Average
13°C Untreated 0 0.28 0.28 0.28
2 6.58 0.27 0.28 0.28
3 6.97 0.26 0.25 0.25
Untrelted 0 0.55 0.56 0.55
2 6.58 0.52 0.54 0.53
3 6.97 0.42 0.46 0.44
UntrOIt-d 0 0.83 0 92 0.87
2 6.58 0.91 0.91 0.91
3 6.97 0.69 0.63 0.66

 

67

 

 

 

. cost-.24,
«arse-ms
flsgL
OSes-lease
0.8 9' 90.
3282.31.38. 11.082.33.38. Iii;

in ion in {film-in in in in inlin Eu '0 in;
3.0 or... 3... «as. o 3.. ad 3... 3 «.0 I 5 3.- vsd Nd I

 

 

o w a (t i4)” 0 u l4 4 — h 4 - t o
_ e e e :83
e e _ :82
_ e s s _ .188
e m :83
a _ .
.188
. . .3. .
e m _ w
b 89 ..

 

 

rmeebility of the sulfonated

Pigure 6.11: Comparison of O, pe

° ° It 13°C. 26°C

edbyll‘ andla

and 35°C with 0%“

PP ion exchang

 

68

 

{‘8'
PS 9! . oh.
.8. .8. .8! .8! e! e! 8.! e8! .8! a. o! .8! .8.
It» Isa Ice is I. '0 'u '0 in En I '0 in in Eu 1
So one lo «a e 3e med one . me «.e e Ed am one am e

r ’ i ’ ’ LI r y . ’

oient of the
and“: at

O

 

P ’

(A .4 -

I 4'

as!"
flee-In.
.8.an

 

1
_
_.
_
__ .
_
..
._
.
_

 

a
diffusion ooeffi

ion exehanged.by la

13°C. 26°C and 35°C with one

sulfonated PP

13: Comparison of Oz

 

 

Figure 5,

l‘-‘
04‘ 9e. 9..
eel 0! .8! .3! o! a! .8. o... a; . 1 E i

in in '0 '81-. '8 '0 in 'fli'n 'N '0
so. a. In. N. I 3.. 3.. CHI II a I 3 3 0%.

b L) P b
i ‘

 

( ( P i P P
4 ( 1 ()

 

 

69

Ella.
3|
.sl'm.

 

n. d
m . ..

u _

. .

..

 

.the sulfonated

by Na, and In. at lIPC, 26°C

and 35°C with 0%“

8
solubility of

.5

3
0

3
mama-mm.

PP ion exchang

 

 

Pigure 6.13: Comparison of

70
plotted as a function of the percent of atomic sulfur on the
surface in Figure 6.14. It was found that as the percent 8
atomic increased, the C02 permeability decreased. The CO2
permeability of the film with 6.5% S on the surface is about
15% lower than that of the film with 5.2% S on the surface.

There results confirm the same trend observed for oxygen

 

permeation studies.

 

6.5 water Vapor Permeation Studies

Water vapor permeability were carried out at 90% RH at a
carrier gas flow rate of 65 cc/min, at 27°C, 33°C, and
37.8°C.

Results of the water vapor permeability studies at 27°C,
33°C and 37.8°C are summarized in Table 6.16. The higher the
sulfonation degree, the higher the water vapor permeability.
This confirms that sulfonation makes PP films moisture
sensitive as previously observed with the oxygen

permeability measurements at 0% RH and 70%RH.

71
Table 6.15: C02 Permeability of the sulfonated PP neutralized

with NHf'at 25°C with 0% RH

 

   

 

 

 

 

 

 

 

 

Sulfonated 5% on the COZ Permeability
“m9 surface 0* (CCJI'II l/m’ .dey.etm)
(min) the film
#1 #2 Average
untreated 0 6478 6834 6656
1 4.14 _ 6201 6399 6300
2-a 5.20‘ 6057 5958 6106 —"
6 .
4 .
6 .

 

 

 

 

 

 

Table 6.16: Water vapor permeability of the sulfonated PP at

27°C, 33°C and 37.8°C.

   
   
     
   
    
 

 

 

 

 

   
   
    
 

 

   
 

  
 
  

 

 

 

 
 
 
 

 

Hater Vapor Permeability
(mam l/e’ .dethn)

Temp. 27°C 33°C 37.8°C
8% on the 0 0.68 0.79 1.20
surface 4.14 0.79 0.92 1.33
of the 5.20 1.13 1.45 2.12
film 1.35 1.84 2.92

 

 

 
 

 

I

 

 

 

‘ A
v v
v v ‘

wen—um

Pigure 6.14: co. permeability e: the alternated PP at ‘-
25 c with our (113")

 

EXPERIMENT ERROR

Sulfonation

1 .

Film Contamination

Although the films were cleaned before sulfonating, some
contamination can not be visually seen. It impacted to
sulfonate films uniformly.

Stability of Oleum

This factor is very important. If the dissolved 803 level
is reduced, it would result in a deviation in SO3 vapor
concentration generated. In the study, the oleum
concentration used was found to be weaker after each run.
It could not generate a consistent SO3 concentration at
each time. The reactor temperature was therefore raised
to obtain the required SO3 concentration or waiting 4
hours more until dissolved 803 level recover.

Batch Process

Since the sulfonation procedure used in the study is a
batch process, it can be lacking consistency compared
with a continuous process. It is not certain how uniform
the sulfonation can be performed within a run and between
the replicate runs which result in variation in
permeation study.

Moisture

73

Permeation

1.

74
Moisture present in the system can react with.SC5 to form
sulfuric acid and the $03 concentration will be reduced
due to above reaction. Although a vacuum pump was used to
withdraw the moisture from the sulfonation chamber, prior
to the sulfonation reaction, the levels of moisture

present in the system of each batch is not certain.

 

Film Samples

The uniformity of sulfonation of the film was variety.
Instrument

The Mocon Ox-Tran 100 and MoCon Permatran CIV were
calibrated with a standard material (PET), 1470 polyester
film from the US department of commerce, National
Institute of Standard and Technology. The Permatran W
used to measure the water vapor permeability was
calibrated with 5 mil standard material and 1 mil
standard material (PET). The sensor Hydrodynamics from
New Part Scientific Inc., was used to measure relative
humidity during oxygen permeability tests. Each run with
a sensitivity error is 2-4%

Temperature

The temperature was controlled within 11°C.

Gas Flow Regulator

75
The flow regulators used to generate an identical flow

rate during the test. The fluctuation of gas flow is ¢5%

 

SUMMARY AND CONCLUSIONS

1. Mild surface sulfonation was found to be very effective
in modifying the barrier properties on the PP films.
Sulfonation was found to reduce the permeability of
oxygen” (Kb at 0% RH as compared to the untreated PP
film.

2. Improvement of the barrier properties on the PP film was
attributed to the presence of SO; at the film surface.
While the sulfonation time increased, the SO34diffused
into the PP film and reacted with PP beneath of the
surface of the PP films. The more the sulfonation time,
the deepest the sulfonated PP layer. The permeability and
diffusion coefficient of sulfonated layer of the PP films
were dramatically decreased when increased the
sulfonation time.

3. Sulfonated PP films are moisture sensitive. Barrier
properties of sulfonated polymers are effected by water
activity. At high relative humidity, the gas barrier is
similar to the untreated PP films. The water vapor
permeability was higher than untreated PP film.

4. Na“ neutralizing counterious exchanged with NH; showed
that the diffusion coefficient reduced but the

permeability of oxygen increased.

76

 

APPENDICES

 

77

APPENDICES

AppendixA

ESCA Analysis

ESCII 5...." 1-‘4/94 NBS“ woman nin

F1291“ SulfH’lIH-Q

Still: “ERIN Lake/S. W588 0.013kc/8 ”NBS.“ 0V
SCIIZSCHIFETIII lake/8. “55k 0.93de I“ GO“

 

 

 

 

 

 

 

 

 

10 J I I I I I I 0‘:
p
C18 .-
9 ‘ m <-
8 " «-
up 4.
7 " w
4- ‘L
5 ‘ $23 “
.4
5 5‘ 2:
z -- _
4 ‘ ‘b
‘ I1: _
3 <
2
l q
o ' I V I
a 29 0

 

II' II‘ n . '
lw WI?“ u - Ina-mm I
no nea~ I -,
Regions Cl 31‘ I
99156 3W

0'
L399 fires Dani-Focus _ IIonocImted

   

 

 

 

I EIenent I area I SensItIvflg I ComenTraTIon I
I I (cts-eV/s) I Factor I (7.) I
F 013 I 30589 I m r 6512—7.
I 013 I 25698 I 9.711 I 22.88 I
I N13 I 3698 I 0.477 I 4.91 I .
I 5322 I 6109 I 9.579 I 6.79 I

 

 

 

 

295
219
229
239
240
259
260
270
280
299
399
319
329
330
389

78

.Appmuuttx B

(h Diffusion Coefficient Calculation Computer Model

REM THIS PROGRAM CALCULATEE THE DIFFUSION COEFFICIENT PRON PERMEABILITY
REN coNTINuous PLow EXPERIMENTS.

REM PROGRAM WRITTEN BY RUBEN J. HERNANDEZ. JAN/19.0% MODIFIED BY JING YI ZHU
REM ON 4-10-98
DIM VISOI. FISDI. TISOI.XISDI.DFISII

REM THE UNITS OF TIME USED WILL DETERMINE THE UNITS IN THE DIFF.COEFF.

 

PRINT “ENTER RELATIVE RUNIoITv IN PERCENT“
INPUT RUN .
PRINT “ENTER THE RUN IDENTIPIcATION NUNsER
REN
INPUT sUN _
PRINT “ENTER THE TEMPERATURE AT STEon STATE
INPUT N -
PRINT “ENTER THE NUNEER OR DATA POINTs
NPUT o . .
;RINT “ENTER THE NILLIVOLUNE v ANo TINE T STARTINR FROM zERo
FOR I-I To 0
PRINT “ENTER v“
INPUT VII)
PRINT “ENTER T“
INPUT TIII
NEXT I .
PRINT “ENTER YOUR RUEss FOR x
INPUT GUESS ~
PRINT “ENTER INPINITE VALUE POR v“
INPUT VI , -
PRINT “ENTER THE AREA RADIO“
INPUT AR
PRINT “ENTER THE PARTIAL PREssURE IN ATN“
INPUT P
PRINT “ENTER THE TRIcRNEEE or THE PILN IN NIL“
INPUT L
PI-VI-Ie

FOR III TO D
DFIII-VIIIIVI

R-.44313‘VIIIIVI
X-GUESS
FOR J-I TO 7

B'SORI
C-EXPI
U-I/B

XI
-X)

H-t.5“U-sI-c
E'IB'CI-A
X-X-(EIH)

NEXT J
XIII-X

GUESSCX

NEXT I

REM LINEAR REGRESSION

.593
420
413
I23
:32:
I40
us
:3-

460
479
439
490
500
519
520
530
539
540
550
560
502
563
504
570
500
610
I320
630
535
see

637
63.
639
649
642
645
846
647
640
659
OR

79

ST-O

SX-O

SXT-O

STSOIE

SXSO-O

FOR I-1 TO D

XIII-II/X(II

ST-ST+T(I)

SX-SX+XII)

SXT-SXT +(XIII'TIIII

SXSOISXSO+IXIII'XIIII

STSO-STSO+(TII)'T(I)I

NEXT I

SLOPE-(ST'SX-O'SXTII(ST'ST-D'STSO)
OUMI-(O'SXTI-(SX'STI

DUM2-(D'STTI-(SX'STI

DUM2-(D'STSOI-(ST'ST)

DUMS-(D'SXSOI-(SX'SXI

DUM4-SORIDUM2'DUM3)

R-OUMIIDUM4

LPRINT "RUN NUMBER: ' SUN

PRINT

LPRINT 'TIME (MINI '.' VOLT '.' X '. "FLOW PERCENT'
FOR l-I TO D

LPRINT TIII.VII).X(II.DF(II

NEXT I

PRINT

PRINT

DIFF-L'L'.99254'.00254‘SLOPEI416O
LPRINT_:OIFFUSION OOEFF IN 6M3/OO¢.." DIF'
LPRINT

LPRINT “THE PERMEAEILITY COEEF IN 0.3.IIIII2.d|V.Itl-'FI'L'ARIP
LPRINT

LPRINT "THE SOLUEILITY IN so 02/00 DOIVIOP - ”2.94E-12'EI'L'ARIP/DIFF
LPRINT

LPRINT ”THE CORRELATION COEEF. -"R'

LPRINT

LPRINT “TEMPERATURE IN C 0' I

LPRINT “WATER ACTIVITY II -' HUMIIII

END

80

Appendix C

Humidity Calibration Curve of Sensor :45-100-153

DIAL READING

 

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81

Appendix D

Data of sulfonation PP analysis from. ESCA, K. wangwiwatsilp
(1993) and J. Tardiff (1993).

 

Sample %S gram of % S gram % total Weight
sample surface of sample gain gram of sample
(ESCA) (K. Wangwiwatsilp) (J. Tardiff)

0 min 0

1 min 10.0 .062 0.098

2 min* 12.3 0.15 1.965

3 min 15.1 0.24 6.845
* Calculation Examples:

%

8 gram of sample surface (ESCA) at 2-a minute sulfonation

 

from Table 6.1
5.204thi, x 100 %
61.76 x C + 25.09 x O + 3.40 x N + 5.20 x S
= 5 29.3.12. x 100 %

 

 

61.76 x 12 + 25.09 x 16 + 3.40 x 14 + 5.20 x 32
12.3 e I g/s)

total weight gain gram of the sample

Weigh;_§§in x 100%
Weight of untreat PP + Weight Gain

 

 

x 100%
0.0499 + 0.001

1.96 % (g/g)

 

 

BIBLIOGRAPHY

 

82

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