Synthesis of Renewable Copolyacetals with Tunable Degradation. Issue 12 (13th April 2016)

• Record Type: Journal Article
• Authors: Rajput, Bhausaheb S.; Chander, Umesh; Arole, Kailash; Stempfle, Florian; Menon, Shamal; Mecking, Stefan; Chikkali, Samir H.
• Is Part Of: Macromolecular chemistry and physics. Volume 217:Issue 12(2016:Jun.)
• Page Start: 1396
• Page End: 1410
• Publication Date: 2016-04-13
• Subjects: copolyacetals -- degradable polymers -- diacetals -- isohexides -- renewable polymers; Polymers -- Periodicals; Polymerization -- Periodicals; Synthetic products -- Periodicals; Macromolecules -- Periodicals; 547.7
• DOI: 10.1002/macp.201600071
• Languages: English
• ISSNs: 1022-1352

Abstract

Abstract : Acetal metathesis copolymerization (AMCP) of renewable isohexide diacetals and aliphatic long‐chain diacetals is reported and access to a small family of copolyacetals has been established. Crucial 1–2D NMR and MALDI‐ToF‐MS findings unambiguously confirm the existence of a copolymeric structure. In a stark contrast to the earlier reported isohexide‐polyacetals, the current copolyacetals reveal very slow degradation. Hydrolytic degradation of copolyacetal pellets is extremely slow at pH 7, whereas only 30% degradation over a period of 15 d is observed in 9m hydrochloric acid solution. GPC investigations reveal that with increasing chain‐length the rate of degradation reduces, whereas copolyacetals with short‐chain aliphatic segments display a faster degradation profile. The reduced rate of degradation can be attributed to the hydrophobic nature of long‐chain acetal segments. In situ NMR spectroscopy reveals the existence of formates, hemiacetals, and diols as degradation products. Thus, the rate of degradation can be tuned by the judicious choice of isohexide‐diacetal and linear‐diacetals in a copolyacetal. Abstract : Acetal metathesis copolymerization of renewable isohexide diacetals and aliphatic long‐chain diacetals is revealed and access to a small family of 15 copolyacetals has been established. The biocompatibility of the copolyacetals is determined by subjecting the copolyacetal to various types of degradation. Degradation investigations reveal that the rate of degradation can be tuned by choosing the right combination of isohexide‐diacetal and linear‐diacetal monomers.