A γ-butyrolactone-derived poly(vinyl ester) with pendant groups recyclability and controlled release of poly(vinyl alcohol): Synthesis, recyclability, and physical properties

Abstract

A pendant group recyclable poly (vinyl ester) [poly vinyl 4-((tert-butyldiphenylsilyl) oxy) butanoate, PVBT] was synthesized by classic free radical polymerization of a γ-butyrolactone (γ-BL)-derived vinyl ester. With the locking by tert-butyldiphenylsilyl group on the pendant groups, the obtained PVBT is stable and available for further processing. When the locking group is removed by adding tetra-n-butylammonium fluoride, the PVBT will decompose to the widely used poly (vinyl alcohol) (PVA) with 100% recovery of γ-BL, which can be reused to synthesize the monomer. In addition, the decomposition of PVBT can be controlled by modulating the removal of the locking group, resulting in PVA with different hydroxyl substituent contents. It was found that the elongation at break of PVBT can reach 8100%, which is 30 times that of polyvinyl acetate (PVAc). Furthermore, the PVBT possesses stronger thermal stability and lower glass transition temperature than PVAc due to their longer and silicon-containing pendant groups.