Studies on thermoplastic polyurethane toughened poly(butylene terephthalate) blends

Poly(butylene terephthalate)/thermoplastic polyurethane (PBT/TPU) blends were prepared using a twin screw extruder. Mechanical and theological properties and morphological characteristics of PBT/TPU blends at four different compositions, viz. 95/5, 90/10, 80/20 and 70/30 were studied. The addition of rubbery TPU to PBT matrix increases the impact strength while tensile and flexural properties decrease. The instrumented impact strength of the blends increased on the addition of TPU and the blend at 5 wt% of TPU content has shown maximum strength. The melt viscosity of the blends shows a linear decrease on increasing the TPU content. The morphological characteristics of the blends were studied using a scanning electron microscope (SEM) which revealed the droplet dispersion of TPU in the PBT matrix. (C) 2002 Published by Elsevier Science Ltd.