Understanding the Dissolution Kinetics of a DINCH Plasticized PVC: Experimental Design and Applied Modeling.

Abstract

Polymer dissolution-precipitation recycling is a promising pathway to increase plastic recycling rates. One of the first steps in this process is the dissolution of the plastic, where it is important to understand and predict the dissolution kinetics, specifically for plastic waste. Therefore, the dissolution kinetics of a plasticized poly(vinyl chloride) sample (P-PVC), containing di-isononyl-1,2-cyclohexaandicarboxylaat (DINCH), were analyzed in N-methyl-2-pyrrolidinone (NMP), cyclohexanone, methyl ethyl ketone (MEK) and 2-methyltetrahydrofuran (2-MeTHF). Additionally, the effects of the particle size (1090 - 2990 µm) and temperature (30 - 60 °C) were studied. As expected, lowering the particle size and increasing the temperature reduced the overall dissolution time. It was also found that the dissolution of the polymer and plasticizer occurred simultaneously, and that the fastest dissolution occurred in NMP, followed by cyclohexanone, MEK and 2-MeTHF. Finally, both a chain disentanglement model and a first order model with a diffusion-based rate coefficient were fit to the experimental data to describe the dissolution behavior of the selected plastic waste. The first was found to be a slightly better description of the P-PVC dissolution profile in NMP, a known good solvent, while the latter was better at describing the dissolution in MEK and 2-MeTHF, the slowest analyzed solvents.