Aqueous Dissolution and Recovery of Poly(Vinyl Alcohol) in Multilayer Film.

In this work, solvent-based recycling was applied to a multilayer film of PBAT-PLA and PVOH, where the dissolution conditions were optimized and the reusability of the recovered PVOH was explored. The use of PBAT-PLA blends provides the possibility of biodegradation, in addition to mechanical recycling. PVOH is used due to its ability to dissolve in water, eliminating the need for toxic solvents in dissolution recycling, and its high barrier properties. The temperature, time, film size, and stirring were explored and optimized for film dissolution in water. After dissolution, the reusability of the recovered PVOH material was explored by comparing its chemical and mechanical properties to those of virgin PVOH material. Stirring experiments showed that films of different sizes dissolve at the same rate with efficient stirring, while smaller film sizes dissolve faster than larger films in the absence of stirring. Characterization of virgin and recovered PVOH showed that the chemical structure of PVOH is mostly maintained after recovery. However, these results also indicate the loss of flexibility and thermal stability of the material due to the loss of important additives.