Recycling of PVC/PU waste and reuse in PVC formulations: Structure-property relationship

Abstract

The possibility of poly(vinyl chloride) (PVC) plasticization and modification by regenerated PVC/polyurethane (PU) blends (PVC/PU R ), obtained after partial thermochemical destruction of the PU foam-backed PVC-sheet (soundproof materials waste), has been studied. The partial thermochemical destruction of the PU foambacked PVC-sheet was carried out using alkanolamine in a one-screw extruder. The destruction product was a thermoplastic mixture of PVC and regenerated linear PUs, applicable for reuse without any purification and fractionation. The influence of processing conditions on structure-property relationships for the PVC/PU R blends was studied using the methods of differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), size exclusion chromatography (SEC), and mechanical testing. It has been established that PVC/PU R blends can be reused as an effective polymer plasticizer for PVC resin (PVC r ) and as a modifier for plasticized PVC (PVC p ). POLYM. ENG. SCI., 45:801-808, 2005.

Investigating the influence of conduit residues on polyurethane plates

“…At the temperature of 52.31 °C, there was a PVC mass loss of 57.68%, and at a temperature of 208.13 °C, mass loss was 87.49% [33,35,39] , completing the decomposition around 300 °C.…”

“…Dehydrochlorination occurred mainly in the first stage of degradation and began at a lower temperature than that observed for PVC. HCl formation may have been catalyzed by PU amino groups [33,35,39,50] . At a temperature of 48.39 °C, there was a 51.39% loss of the total mass of the sample, which means that urethane bond-breaking also occurred at a lower temperature than that observed for the PU.…”

“…It is widely accepted that PVC dehydrochlorination involves a gradual reaction between chlorine and hydrogen atom neighbors in the polymer chain, comprising a double bond between the carbon atoms in positions in which the two atoms were originally connected, forming a structure of allylic chlorine with another chlorine atom of the polymer chain [11,33,35,39] . Complete combustion leads to the formation of hydrochloric acid, carbon dioxide and water.…”

“…At 325.00 °C, the mass loss was 45.43%, and complete degradation occurred at 770 °C. The first and second PU decomposition steps correspond to urethane bond-breaking and polyol decomposition, respectively [8,39,50,51] .…”

“…PVC was incorporated into the foam components by simple mechanical mixing at the compounding stage. This is still a relatively unexplored method, and this study is intended to contribute to analyze PVC compatibility with PU [32][33][34][35][36][37][38][39][40] . This paper presents an analysis of the conduit residue (PVC) incorporation into polyurethane to obtain plates, in order to investigate whether this material presents flammability reduction and improvement of thermal and mechanical properties.…”