The research work is divided into two parts. The first part is motivated by the need to produce recyclable lighter and thinner injection molded thermoplastic polyolefin (TPO) foam parts for automotive interiors by chemical foaming agent. This would require modifying the talc filled TPO compound with organoclay additive that can not only control the cell size to be smaller and more uniform, but also attain a smooth surface of the foamed parts. The objectives of this research were (1) to investigate the effect of different level of vapor phase silane coupling agent treatment on increasing the d-spacing of organoclay and the extent of dispersion in polypropylene; (2) to understand the relationship between melt rheology, surface appearance, foam morphology and mechanical properties of foam injection molded talc filled TPO and organoclay additive with optimized level of vapor phase silane pretreatment.TPO nanocomposites were prepared with organically modified montmorillonite, a silane coupling agent, maleic anhydride grafted polypropylene as compatibilizer and a commercial grade TPO with 23 wt% talc loading. The organoclay was treated with 0.8 wt% of the silane coupling agent under vapor phase process to improve the interaction between the clay and the TPO to reduce the usage of low viscosity compatiblizer. The rheology of the TPO and TPO nanocomposites was examined in shear and extensional flows and this was used to select the molding temperature profile. The effects of different molding parameters- extrusion back pressure and pack pressure on the uniformity of thickness, and cell structure were examined. Stronger shear thinning behavior was conducive to a smooth surface of molded parts, allowing an operating temperature profile close to that used for the base TPO and was crucial for both smooth surface and smaller cell size. The tensile strength, tensile modulus and flexural modulus were tested to be greater for the foam injection molded TPO nanocomposites. The second part of the research was motivated by the need to produce a thinner battery separator for nickel-metal hydride batteries (NiMH) that had higher tensile strength and puncture strength. This was achieved by solid phase die-drawing of talc-filled polypropylene to produce stronger and porous sheet with up to 40% void fraction. The objective of this research was to explore process limits and products obtained from two different composites with different talc particle size distributions. The limiting maximum linear draw ratio without breaking was higher for the composite with the smaller mean particle size; this may be attributed to the smaller transverse dimension of stacked voids obtained with this material. At the respective limiting linear draw ratios, the porosity level is the same for both composites but the composite with the smaller talc particle sizes and higher draw ratios led to drawn sheets with greater tensile strength; this may be attributed to greater crystalline rearrangement to fibrils in this composite at higher linear draw ratio.
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