Investigation of Shape Memory Behavior and Physical Properties of Crosslinked Low Density Polyethylene/OvPOSS/TAIC Composites

摘要

The aim of this study is to investigate the shape memory behavior and physical properties of crosslinked low density polyethylene (LDPE)/Octavinyl functionalized polyhedral oligomeric silsesquioxanes (OvPOSS)/triallyl isocyanurate (TAIC) composites. Shape memory polymer can return from its temporary shape to the original (permanent) shape upon heating. One of the most widely used shape memory polymers is crosslinked polyethylene. Polyhedral oligomeric silsesquioxanes (POSSs) organic/inorganic hybrid materials are new the generation of nanofillers that can be used to increase the crosslinking efficiency of LDPE. OvPOSS nanoparticles having reactive functional vinyl groups and TAIC were used as coagents. On the other hand, 1 phr of di tert-butyl cumyl peroxide (BCUP) was used as a crosslinking agent in this study. LDPE/OvPOSS/TAIC/Peroxide composites were prepared in an Xplore model twin screw micro-compounder at a screw speed of 50 rpm and 135°C barrel temperature. The crosslinking was carried out using a hot-press operated at 175°C. The composites were characterized by performing tensile tests, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), rheology and shape memory tests. Rheological test results showed that the degree of crosslinking, storage and loss modulus of LDPE/TAIC system increased by the addition of OvPOSS and TAIC. It was obtained from DSC analysis that LDPE/OvPOSS/TAIC/Peroxide composites exhibited lower melting enthalpy values, which can be attributed to the restricted chain mobility of LPDE in the presence of OvPOSS and PRX.