STRESS-STRAIN BEHAVIOR AND CRYSTALLIZATION DURING UNIAXIAL DRAWN PET/MMT NANOCOMPOSITES ABOVE GLASS TRANSITION TEMPERATURE

摘要

Uniaxial tensile tests of poly (ethylene terephthalate) (PET)/montmorillonite(MMT) nanocomposites were preformed over a temperature range of 85℃-105℃ and stretch rate of 7.5mm/s-12.5mm/s. The stress-strain curves consisted of three regions: the linear visoelasticity, the rubbery plateau and the strain hardening. The effects of temperature and stretch rate on stress-strain behavior were discussed. The results of differential scanning calorimetry (DSC) measurements indicated that the stretch lead the increase of the crystallinity degree of specimens. The wide angle X-ray diffraction (WAXD) measurements revealed that the more perfect crystal structures were obtained with the increase of temperature and oriented along the stretch direction.