Influence of surface treatment of fillers on the mechanical properties of thermoplastic polyurethane composites

Tayfun, Ümit
The incompatibility between filler and polymer matrix is the major restriction for the production of composites to have desirable properties. Several surface modification methods are applied to filler surface in order to improve the interfacial adhesion with polymer matrix. Easy processablity and fully recyclability character of thermoplastic polyurethane (TPU) make it cost effective for many applications. Majority of TPU application is across a range of markets including automotive, sporting goods, medical devices, tubes, hoses, wires and cables. The objectives of this research are the enhancement of interfacial interactions between several fillers and TPU matrix by applying surface treatments and investigation the effects of these treatments on the mechanical properties of TPU based composites. The surface of fillers after modifications were characterized with fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray spectroscopy (EDX). Pristine and surface functionalized fillers were incorporated in TPU matrix by using melt-blending method. Two types of TPU composites, green polymer composites and carbonaceous fillers reinforced composites were prepared. Mechanical properties, melt flow characteristics and morphologies of the composites were evaluated by using tensile, dynamic mechanical analysis (DMA) and Shore hardness tests, melt flow index (MFI) test and scanning electron microscopy (SEM), respectively. Surface modifications of fillers resulted in better mechanical properties for their composites as compared with untreated ones. SEM micrographs revealed that surface treated reinforcers dispersed more homogeneously than untreated fillers in the TPU matrix. Results confirmed that surface modifications improved the adhesion of fillers to TPU.