Effectiveness of high frequency heating on drying and intrinsic viscosity enhancement of recycled poly(ethylene terephthalate)

The effectiveness of a high radio frequency (HF) heating technique as a tool for drying and for enhancement of intrinsic viscosity (IV) in recycled poly(ethylene terephthalate) (R‐PET) pellets is described. R‐PET that was sourced mainly from postconsumer drinking bottles would generally attain lower molecular weight due to hydrolytic degradation when exposed to repeated thermal processing cycles and also the presence of impurities. Hence, the IV of R‐PET would be significantly lower as compared to virgin PET (V‐PET), which could affect its processability and significantly limit its application. In this study, R‐PET pellets were exposed to HF and their IV and moisture content were monitored with time. HF was found to be a less time consuming method to enhance the IV of R‐PET although it was not reliable to be used for drying purposes.