Polyaddition of Discrete Oligo(butylene succinate)s with Divinyl Ethers for Periodic and Selectively Cleavable Main-Chain Acetal Linkages

Poly(butylene succinate) (PBS) is a promising biodegradable and sustainable thermoplastic, but its poor degradability in marine environments is a cause for concern. In this study, we aimed to mitigate this issue by developing novel PBS derivatives with labile acetal linkages periodically distributed along the polymer backbone. An efficient protection-deprotection synthesis yielded monodisperse dihydroxy oligo(butylene succinate)s (OBS) with precisely controlled molecular weights, which were consequently employed as the telechelic macromonomers to be polymerized with divinyl ethers in a step-growth fashion. The obtained poly(OBS-acetal)s had high-molecular-weight (M_n > 100,000 Da) and showed PBS-like semicrystalline properties due to the presence of well-defined crystallizable OBS segments joined together by labile spacers. Selective cleavage of the backbone acetal linkages under acidic conditions enabled rapid depolymerization into simpler oligomers with better degradability. Therefore, this general strategy could be utilized to improve the degradability of the polymers while retaining their physical properties.