Mechanochemical reclaiming and thermoplastic re-processing of waste Acrylonitrile-butadiene rubber (NBR)/poly (Vinyl Chloride) (PVC) insulation materials

Cross-linked acrylonitrile-butadiene rubber (NBR)/poly(vinyl chloride) (PVC) blends are extensively served as commercial insulation foams. However, methods to reclaim the wasted NBR/PVC composites are usually inappropriate, causing severe pollution. Herein, we reported that the waste NBR/PVC composites powders (WNPP) with high thermal stability and degree of reclaiming were prepared by solid-state shear milling technology (S3M). Furthermore, the reclaimed products via thermoplastic re-processing had excellent mechanical properties, and the optimal stress and strain were increased by 208.2 % and 269.4 %, respectively, compared with the products made from virgin scraps. Through the investigation of each sample's molecular chains and thermal properties, it was found that when the cross-linked polar rubber-plastic composites are reclaimed, the molecular chains of the rubber phase would be close to each other. The interaction among polar groups would be enhanced, which is the main contributing factor limiting the movability of the polymer chains. And the interaction between the polar rubber and plastic phases would also increase, which is beneficial for the compatibility of the two phases. Moreover, there is a phase separation between the de-crosslinked continuous phase and the residual cross-linked network region for the re-processing products.