A review is given of the structure of semi-crystalline polymers and the mechanisms of plastic deformation in them. High-density polyethylene (HDPE) is taken as the specific example because of the large number of detailed studies performed on this material. The early findings are also compared and contrasted with very recent detailed large-strain deformation studies and computer simulations of deformation-induced texture development in HDPE.

Structure and plastic deformation of polyethylene

Toughness mechanism in semi-crystalline polymer blends: II. High-density polyethylene toughened with calcium carbonate filler particles

Strength and toughness of crystalline polymer systems

Toughness mechanism in semi-crystalline polymer blends: I. High-density polyethylene toughened with rubbers

Deformation, yielding, fracture and fatigue behavior of conventional and highly cross-linked ultra high molecular weight polyethylene

A micromechanically-based composite model is proposed to study large plastic deformation and texture evolution in semi-crystalline polymers. The microstructure of many semi-crystalline polymers consists of co-existing crystalline and amorphous phases locally associated with each other in a fine plate-like morphological structure. An aggregate of two-phase composite inclusions is used to model these materials. Special consideration is given to molecular chain inextensibility within the crystalline phase. The introduction of a back stress tensor in the constitutive model of the amorphous phase accounts for hardening due to deformation-induced molecular alignment. Interface compatibility and traction equilibrium are enforced within each composite inclusion. A Sachs-like model and two newly-developed self-consistent-like hybrid models are proposed to relate volume-average deformation and stress within the two-phase composite inclusion to the remote (macroscopic) fields. Applications of these composite models arc made to predict stress strain behavior and texture evolution in initially isolropic high density polyethylene (HOPE) under different modes of straining.

B.J. Lee

Papers

Micromechanical modeling of large plastic deformation and texture evolution in semi-crystalline polymers

Simulation of large strain plastic deformation and texture evolution in high density polyethylene