No abstract

No abstract

No abstract

In this paper, we discuss the application of different micromechanical composite models to compute the effective elastic properties of semicrystalline polymers. The morphology of these two-phase materials consists of crystalline lamellae and amorphous domains which may form a spherulitic microstructure. The selected models are the Mori-Tanaka type models, the Double-Inclusion models, and the Self-Consistent models. We applied these composite estimates to both fully isotropic and transverse isotropic transcrystalline polyethylene. The results from these different models are compared to the experimental results for different crystallinities. The Generalized Mori-Tanaka (GMT) model and the Self-Consistent Composite-Inclusion (SCCI) model give the best predictions of the effective elastic constants compared to the other models.

The elastic modulus and yield stress behaviour of a melt intercalated Poly(methylmethacrylate)/ organoclay (PMMA/C30B and PMMA/C20A) were studied using uniaxial tensile tests at different temperatures and different strain rate. The stress-strain response was obtained for different loading rates and different test temperature. Both the stiffness and the yield stress were then clearly identified as function of strain rate and temperature. Our experimental results show that the yield stress and modulus of both PMMA/C20A and PMMA/C30B organoclay nanocomposites are very sensitive to clay concentration, strain rate and temperature. A micromechanically-based composite approach was used to predict the yield stress of both PMMA/C20A and PMMA/C30B organoclay nanocomposites. The results obtained from the model are in good agreement with our experimental results. As expected, the activation enthalpy of cooperative model increased slightly while the activation volume decreases slightly with the clay concentration.