Multiscale Models of Structure and Deformation Behavior of Semicrystalline Polymer

摘要

In the present study, we clarify the micro- to mesoscopic deformation behaviors of semicrystalline polymers under tension, compression and shearing by the finite element homogenization method. The crystalline plasticity theory using a penalty method for the inextensibility constraint in the chain direction and the nonaffine molecular chain network theory were used to model deformation behaviors of crystalline and amorphous phases, respectively, in the composite microstructure of a semicrystalline polymer. The mesoscopic structure of a semicrystalline polymer was modeled using a voronoi polygon composed of composite microstructures with different lamella interface directions. The initial isotropy of the response of the mesoscopic scale was verified. Due to their interaction with the surrounding grains, the individual grains on the mesoscopic scale show a conservative response as compared with that of the unit cell, and a very nonuniform response depending on the location of the respective grain is observed; these are typical of the mesoscopic response of semicrystalline polymers. The crystallinity-dependent characteristic deformation behavior under different straining has been clarified.