Rheological and Mechanical Properties of Recycled PET Modified by Reactive Extrusion

The effect of chain extender on the improvement of molecular structure and elongational properties under molten and solidified states of recycled Poly(ethylene terephthalate) (RPET) was studied. The results suggested that addition of chain extender increased the molecular weight and broader molecular weight distribution of RPET. A gel fraction of cross-linked material was formed and the concentration of gel content being dependent of the amount of chain extender used. Increasing chain extender resulted in increases in elongational viscosity of RPET. The increases in viscosities were explained in association with the extension of RPET chains, causing a reduction in chain mobility. The tensile properties in molten and solidified state were found to increase with increasing chain extender up to 0.6 wt% before it decreased at the chain extender loading of 0.9 wt%. (C) 2014 Elsevier Ltd.