Chemically recycled polyvinyl chloride as a bitumen modifier: synthesis, characterisation and performance evaluation

Polyvinyl chloride (PVC) is one of the most widely produced thermoplastic polymer, used in the manufacture of a variety of valuable short and long life products. Nevertheless, the increasing demand for PVC and current ineffective disposal methods have made it a potentially severe environmental hazard. The chemical recycling of PVC through hydrolytic or aminolytic routes has shown significant promise, however, their end applications have been limited as of now. This study is concerned with the chemical modification of PVC by amines into additives, and its ensuing use as a performance enhancing modifier for bitumen. In view of this, additives were firstly synthesised by the amination of PVC with two kinds of polyamines; triethylenetetramine (TETA) and ethylene diamine (ED) respectively. These were then chemically characterised by solid state Nuclear Magnetic resonance (NMR) and elemental analysis. Subsequently, the aminated PVC additives were blended with virgin asphalt binder and its effectiveness was evaluated in terms of moisture susceptibility and rheological properties. The results of the preliminary laboratory studies indicated that the binders modified with the additives showed significantly improved anti-stripping properties and overall rheological performance as compared to conventional binder. Overall, the usage of such waste PVC based additives as modifier for bituminous mixtures represents an innovative approach to deal with a relevant recycling problem while simultaneously recovering a value-added material.