Polyurethane, a versatile polymer, can be produced in various forms like flexible foams, rigid foams, elastomers, coatings and adhesives with a wide range of properties. Traditionally, polyurethanes are prepared by reacting polyols and diisocyanates. The overall objective of this research was to investigate the feasibility of using readily available and relatively cheap soy meal as a starting material to produce biobased urethane polyols for polyurethane. The amine groups, already present in the soy meal protein, can be converted to urethane polyols. In this study, these hydroxyl-terminated urethanes were further reacted with dimethyl terephthalate in a two-step reaction to obtain polyurethanes without employing the toxic isocyanate reagent. Glycine, an amino acid found in soy meal was used as a model compound for this study for understanding the chemistry and developing the process. The structures, properties of the intermediates and products were characterized by 1H NMR, FTIR, acid, amine and hydroxyl values, as well as the key thermal, rheological, morphological properties of the polymer were analyzed.. In the next phase of this study, these developed polyols were further reacted with isocyanates and evaluated in rigid polyurethane foams. A commercial sucrose based polyol was used as a reference petroleum-based polyol. Foams were prepared at Isocyanate Index of 105-110. PU rigid foams with 25% and 50% soy meal polyol formulations exhibited comparable properties to foams prepared with 100% commercial conventional polyols for rigid foams, including density, compressive strength, compressive strain at yield, friability, water absorption, burning rate and dimensional stability with aging. A relatively simple method was developed for routine determination of hydroxyl values for a wide range of hydroxyl containing compounds including soybean oil polyols, polyether polyols, ethylene glycol and their blends. This method was based on reacting the hydroxyl compound with hexamethyldisilazane (HMDS) and determining the FTIR peak area of the silylated product at 1251 cm -1. This method is simple and accurate and is not limited to a specific family of polyol compounds. It does not require any special equipment or hazardous chemicals and can be carried out by non-technical staff as a rapid and convenient method for quantitative determination of hydroxyl values. An excellent linear correlation was obtained between this spectroscopic method and conventional titration methods for different types of polyols over a wide range of hydroxyl values. Furthermore, unlike the titration methods the current method is not affected by the presence of acid, base or small amounts of water in the test sample. Further, the soymeal polyol and castor oil have been further utilized for synthesizing aqueous polyurethane dispersions for coating applications on paper and cellophane substrates. The coatings were further evaluated for various properties using contact angle analysis, viscosity measurements, scanning electron microscopy, barrier properties against water vapor and oxygen permeation. In the last phase, biodegradability studies that were carried out during the course of the study on polyvinyl alcohol, soymeal polyol and castor oil based polyurethane films according to different standards are reported and discussed.
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