Dissolution of adhesive resins present in plastic waste to recover polyolefin by sink-float separation processes

Abstract

This study investigated the dissolution of adhesive resins present in polyolefin films that cause plastic materials to adhere to each other. The process of dissolution was made by the use of ethyl acetate and followed by separation through the sink-float process. The objective was to separate and characterize polyolefin films from plastic solid waste derived from recycled post-consumer paper. Through these procedures, 6% polyethylene of high-density (HDPE), 14% polyethylene of low-density (LDPE) and 39% polypropylene (PP) were separated and recovered from plastic waste. Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analyzes (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA) were conducted to determine the chemical, thermal and mechanical properties of the recovered polymers and to establish a comparison with standard commercial polymers. It demonstrated that recovered material kept their chemical, thermal, and mechanical properties. This process indicates possible economic viability considering the demand, the market value of the PP, and the required investment to be implemented in the recycling process that could be amortized in a short period of time. Moreover, the organic solvent used in the dissolution process can be easily recovered by distillation.

Keywords: Natural solvent; Plastic waste; Polyolefin film; Separation.