Micromechanical Modeling Of Isotropic Elastic Behavior Of Semicrystalline Polymers

Semicrystalline polymers are increasingly being used as structural materials. With the crystalline polymer materials in structural engineering applications more widely, people microstructure of crystalline behavior of polymer produced widespread interest in macroscopic mechanical properties and in particular the relationship between the microstructure is obtained academic attention.This micromechanical modeling based on composite materials, crystalline lamellae are the reinforcing phase while the amorphous phase is the matrix.the use of composite materials, micromechanics differential method to establish the relationship between macro.and micro performance to achieve the degree of crystallization under different macro-mechanical properties of the forecast products.The four major works are as follow:1. Rules for other crystalline polymers such as polypropylene spherulite structure, according to the molecular chain structure and interactions between atoms calculated the mechanical properties of crystalline phase in the high-elastic state under such regulations under the weight average molecular weight crystalline polypropylene and calculated the density of amorphous phase shear modulus, and then released under the 1995 U.S. standard polymer PVT data obtained bulk modulus and Poisson's ratio, and finally according to the relationship between the calculated elastic modulus of amorphous phase, finally got a crystal ball crystal structure and mechanical properties of amorphous phase2. The polypropylene spherulite crystal polymer as a mixture of composite materials with that of non-crystalline phase as matrix material, crystalline phase of crystalline lamellae for the inclusions (enhanced material.) Mixture of theory-based composite materials, building on the crystallization of polymer composite micro-mechanics model3. Using the differential scheme and Mori-Tanaka scheme, the crystalline lamellae as ellipsoid, coin type and spherical inclusions were calculated according to different crystallinity polypropylene and other mechanical properties of crystalline polymer, and the literature with a comparative analysis of experimental results have achieved satisfactory results, and finally construct the crystalline polymer microstructure and macroscopic mechanical properties of relations.This thesis is supported by the National Natural Science Foundation(10872186).