Experimental investigation and numerical simulation for structural evolution and stress distribution during the stretching process

Abstract

AbstractIn the preparation of polyethylene (PE) microporous membrane, the stretching process of PE/liquid paraffin (LP) blend is of great significance for improving the mechanical properties and optimizing the pore size and its distribution. In this study, we have adopted a method that combines experimental investigation and numerical simulation to explore crystal structure transformation and residual stress distribution of PE matrix during the stretching process. First of all, the X‐ray diffraction, small‐angle X‐ray scattering test, and tensile strength test are used to analyze these PE/LP blend samples that are processed at different stretching temperatures (110°C, 115°C, 120°C, 125°C) and different stretching ratios (2 × 2, 3 × 3, 4 × 4, 5 × 5). It is found that a higher temperature or larger ratio is beneficial for crystallizing of PE long chains and affecting the tension strength. After the extraction process, the obtained PE microporous membranes have more uniform pore size distribution and an increased pore diameter according to the results of scanning electron microscopy and porosity test. It is attributed to the fact that residual stress is more easily stored in the amorphous region of PE microporous membrane. PE microporous membranes can have higher crystallinity and well‐dispersed crystal region by controlling a matched temperature and ratio. It is inspired for optimizing the technological parameters in industrial production.