Developing electrically conductive nanocomposite using polyvinyl chloride foam waste containing vulcanized rubber

Session: PMSE/POLY Poster Session:  

Global plastic production has increased more than 200-fold over the last 70 years, reaching 7.8 billion tonnes of plastic since 1950 cumulatively, from which 42% has been landfilled, 29% incinerated for energy recovery, and 29% recycled. This massive amount of plastic waste has accounted for a myriad of ecological and health problems since most plastics are not biodegradable. This research aimed to develop electrically conductive nanocomposites by melt mixing of polyvinyl chloride (PVC) foam waste with carbon nanotube (CNT), as the conductive filler. However, we realized that provided PVC foam waste contains 60% volcanized rubber, making it non-meltable. Devulcanization of rubber could be a solution to this problem; nevertheless, it is energy intensive and deteriorates the physical properties of the final product significantly. Inspired by the volume exclusion effect, we propose a novel strategy to reuse PVC foam waste as secondary dispersed component in polystyrene as the binder as well as host matrix for conductive nanofiller (i.e., CNT). The melt mixing of PS/PVC/CNT is possible and results in double percolation structure (i.e., percolation of conductive filler in the continuous phase), leading to desired conductivity at much lower CNT loadings. For instance, PS/PVC (70/30 wt.%) filled with 0.7 wt.% CNT conducted electricity 4 times better than PS filled with 1.0 wt.% CNT. The employed strategy is an example of upcycling so that non-biodegradable PVC foam waste is used as a resource.