Mechanical Properties of Polymer Crystals

Mechanical property of a crystal lattice is the ultimate mechanical property of the bulk polymer samples composed of the crystalline and amorphous phases. The principles and techniques of the experimental and theoretical evaluations of the mechanical property of the crystalline region are described concretely. In the actual experimental process, the heterogeneous stress distribution in the bulk samples must be taken into account in order to evaluate the true mechanical property of the crystal lattice. The thus experimentally-obtained mechanical properties of the crystal lattice are interpreted theoretically on the basis of chain conformation and chain packing mode. These studies allow us to obtain some ideas to enhance the mechanical property of polymer matrials. The effect of such an external field as temperature, humidity or stress on the structure and mechanical property of the crystalline polymers is described for the several case studies. In addition, the microscopically-viewed mechanisms of fracture and friction are learned.