Influence of Calcium Carbonate Fillers on the Properties of Recycled Poly(e-caprolactone) Based Thermoplastic Polyurethane

Abstract

In this work the effects of different crystallographic modifications of calcium carbonate (CaCO₃) filler on the melt flow, mechanical properties, hydrolytic degradation, and shape memory behaviour of recycled low-temperature poly(e-caprolactone)-based polyurethane (rTPU) were evaluated. Composites were prepared by two-roll milling varying filler content from 2 wt % to 6 wt %. It was found that at temperature range from 20 °C to 50 °C CaCO₃ fillers do not change Young’s modulus, they decrease tensile stress and deformation of rTPU, but improve its mechanical properties at elevated temperatures (up to 65 °C). rTPU melt flow index increases due to chain scission during the recycling and filler mixing with mill. Therefore, destruction temperature of rTPU is 20 °C lower than that of TPU. The CaCO₃ does not change shape memory properties independently of filler type and transition from secondary shape to the primary shape at 70 °C temperature is completed within 17 s for both filled and unfilled rTPU. The investigation of hydrolytic degradation shows that CaCO₃ only slightly increases degradation rate of rTPU.

DOI: http://dx.doi.org/10.5755/j01.ms.18.3.2433