Study of the Interaction Between Oligomerised Recycled Poly(ethylene terephtalate) and Concrete Waste

Aiming to assess the feasibility of a one-step processing, comprising simultaneously the mixing of polymer/filler and the modification of the particle surface, we prepared composites of recycled poly(ethylene terephtalate) and micronized concrete waste particles, using an oligomerising agent. The goal was to partially oligomerise the recycled polymer and foster the chemical modification of the concrete particles surface with these oligomers, to improve the dispersion and adhesion of the filler in the polymeric matrix. The composites were evaluated by thermogravimetry/derivative thermogravimetry, differential scanning calorimetry, Fourier transform infrared spectroscopy, wide angle X-ray diffractometry and rheological measurements. There was an improvement in the crystallizing effect of the filler in the composites with oligomerised polymer. We noticed a trend of reaction between the citric acid and the poly(ethylene terephtalate) oligomer in the Fourier transform infrared spectroscopy results. From the wide angle X-ray diffractometry analysis we assessed that the presence of the filler had more influence in the crystallinity of the recycled poly(ethylene terephtalate) than the degradation caused by the citric acid. The rheological measurements showed an increased cohesion of the internal structure of the materials in the oligomerised samples. We conclude that there is a pathway to obtain composites of recycled poly(ethylene terephtalate) and surface-modified concrete waste particles in a single step, by partially oligomerising the polymer in the molten processing.