Effect of thermoplastic polyurethane content on properties of PC/TPU blend filled with Montmorillonite

Abstract

The present study was taken up to investigate the effect of addition of Montmorillonite (MMT) to Polycarbonate/Thermoplastic polyurethane (PC/TPU) blends. A master batch of PC/MMT (70/30) was prepared using Hake Rheomixer and PC/TPU blends filled with MMT of different compositions (90/10/5, 80/20/5, 70/30/5) were prepared by melt mixing using required quantities of master batch, PC and TPU in a twin screw extruder (TSE). Blends of PC/TPU of similar compositions (without MMT) were also prepared using twin screw extruder. The test specimens were prepared by injection molding. The samples were characterized in terms of mechanical (as per relevant ASTM standards), thermal and dynamic mechanical properties. It was observed that addition of 5 phb of MMT to PC/TPU system improves tensile strength by 34 %, flexural strength by 8.6 % and flexural modulus by 16.7 %, storage modulus by 25 % and Shore D hardness by 16 % in all the compositions containing MMT. Differencial Scanning Calorimetric (DSC) and Dynamic Mechanical Analysis (DMA) studies revealed that the Tg shift towards lower values when compared with neat PC.The heat deflection temperature (HDT) of blends with MMT was found to increase with the reinforcement.

Keywords

• Montmorillonite
• Polycarbonate
• Polyurethane