Synthesis and Chemical Recycling of Novel Poly(ester‐urethane)s Using an Enzyme

Abstract

A series of enzymatically recyclable poly(ester-urethane)s consisting of a biodegradable diurethane moiety as a hard segment and an ester moiety as an enzymatically cleavable linkage was chemo-enzymatically prepared by two routes. The poly(ester-urethane) was prepared by a) the ring-opening polymerization of a cyclic ester-urethane monomer synthesized via the transesterification reaction of biodegradable diurethanediol and dicarboxylate ester using lipase and b) the direct polycondensation of a diurethanediol and a dicarboxylate ester. A significantly higher molecular-weight poly(ester-urethane) having the highest molecular weight (Mw) of 101,000 was produced by the ring-opening polymerization of the cyclic ester-urethane monomer when compared with that produced by the polycondensation of the dicarboxylate ester with diurethanediol. The poly(ester-urethane) was readily degraded by lipase into the corresponding cyclic oligomers; the oligomers were readily repolymerized by the ring-opening polymerization using lipase for chemical recycling.

Enzymatic Synthesis of Polyesters via Ring-Opening Polymerization

“…Under the same conditions, the polycondensation of diethyl adipate and 1,4-butanediol produced a lowermolecular-weight polyester [77]. A larger-membered cyclic ester-urethane oligomer was also readily polymerized by lipase CA to produce a highermolecular-weight poly(ester-urethane) with the highest molecular weight of 103 000 [78]. Based on these results, ring strain may not be primarily responsible for the ring-opening polymerization of cyclic macrolides.…”

Synthesis and Enzymatic Degradation of Environmentally Benign Poly(carbonate/ester-urethane)s Containing Lactide Oligomer

“…[7,8,[12][13][14][15] According to previous papers, these enzymatic degradations might be applicable to the chemical recycling of PC/LU.…”

“…Thus, the produced poly(carbonate-urethane) and poly(ester-urethane) are chemically recyclable by lipase in addition to being biodegradable. [7,8] Poly(L-lactic acid) attracts attention as a versatile aliphatic compostable plastic that is available from agricultural renewable resources by the combination of fermentation and chemical polymerization. Poly(L-lactic acid) having hydroxyl end groups can be used to produce L-lactic acid based poly(ester-urethane).…”

Applications of Enzymes in Synthesis and Modification of Polymers

“…Uma massa molar maior de PEU foi obtida pela ROP de éster-uretano cíclico (101.000 g/mol) quando comparado à policondensação direta de diéster ácido dicarboxílico com DUD (31.000 g/mol), ambas catalisadas por esta lipase, em condições de reação de 110 ºC. 60 Apesar do interesse por esse tipo de reação, cabe ressaltar que ligações éster são suscetíveis à hidrólise em meio alcalino, reduzindo, assim, a resistência do polímero. Ligações do tipo carbonato podem ser introduzidas em substituição às ligações éster, sendo assim mais resistentes à hidrólise em meio alcalino.…”