| Summary: | 碩士 === 長庚大學 === 化學工程研究所 === 87 === AbstractThe strong correlation between microstructure and physical properties of thermoplastic polymer materials have been important areas for polymer research. The physical properties include mechanical, optical, electrical and transport properties of a solid state polymer and rheological and crystallization/solidification behavior of a polymer melt. They are all dependent upon the crystal morphology and yet microstructural level elements, such as chain branching and chain branching distribution (CBD), molecular weight and molecular weight distribution (MWD), blending compositions and the processing techniques employed. The recent development in metallocene catalyst technology has led tremendous advancement in the polymerization of ethylene copolymers. New class of polymer products with unique properties can be designed through molecular structure tailoring. The molecular weight distribution is narrow and the comonomer distribution is homogeneous compared to their Ziegler-Natta counterparts. The controlled chain microstructure thus provides a unique opportunity to model structure-property relationships for both academia and the industry. In the system of ethylene-octene copolymers, a wide range of octene incorporation can be achieved to produce very high density polymer (HDPE-like) through very low density polymer (elastomer-like). The study focused on this new class of ethylene-octene copolymers with different levels of comonomer content. The processing-structure-property characteristics have been investigated through experiments. Blends with conventional thermoplastic polypropylenes were evaluated.
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