Probing the Fundamentals of Polymer Melt Crystallization

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9732653 Hsaio The main objective of the proposed research is to explore several fundamental issues of polymer melt crystallization, which include early stages of phase transformation, secondary crystallization and deformation-induced crystallization. The rationale for the proposed study is as follows. It is now firmly established that, in polymer melt, long-chain molecules can crystallize into a two- phase structure with periodic arrangement of lamellae and amorphous interlayers under quiescent and flow conditions. Although the kinetics of the process can be understood with nucleation and growth theories, the mechanism of forming a two- phase structure at short and long time scales under these conditions, requires further clarification. The proposed research is intended to systematically study the fundamental behavior of melt crystallization in polymers with different molecular architecture, chain stiffness, molecular weight and chain branching using several advanced characterization techniques including time-resolved simultaneous synchrotron SAXS/WAXD, microscopy, light scattering and thermal analysis. %%% The significance of this work lies in the probable universal behavior of the phase transformation during melt crystallization, in the enormous multiplicity of macromolecules, that is yet to be completely understood. With the proposed study, an in-depth understanding about the subject may be obtained. This can significantly improve the ability to correlate the structure, morphology, process and property relationships in the applications of crystalline polymers. ***