UNDERSTANDING THE MOLECULAR WEIGHT DISTRIBUTION SHAPE-PROPERTY RELATIONSHIP BASED ON LINEAR UNIMODAL AND BIMODAL POLYETHYLENES MODEL SYSTEM
Molecular weight distribution (MWD) shape is crucial in determining the properties of polymers. Previous studies on comparison of the unimodal and bimodal MWD shape without controlling dispersity, chain branching, phase separation or average molecular weight make it hard to decouple the independent contribution of MWD shape. In this work, we have successfully synthesized unimodal and bimodal polyethylenes with low branching, good miscibility, narrow dispersity and well-defined MWD shape. With this polymer model system, we have systematically studied the impact of bimodal MWD shape compared to unimodal MWD shape in terms of crystallization, rheology and mechanical properties in order to establish the MWD shape-property relationship of semicrystalline polymers.
unimodal, bimodal, molecular weight distribution, MWD shape, polyethylene, crystallization
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