Organocatalytic strategy to telechelic oligo(ε-caprolactone-co-p-dioxanone): Photocurable macromonomers for polyester networks. (5th December 2020)

• Record Type: Journal Article
• Authors: Fuoco, Tiziana; Nguyen, Tran Tam; Kivijärvi, Tove; Finne-Wistrand, Anna
• Is Part Of: European polymer journal. Volume 141(2020)
• Publication Date: 2020-12-05
• Subjects: Telechelic oligomers -- Reaction kinetics -- Reactivity ratio -- Control of the structure -- Degradable networks; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; Polymerization; Polymers; Periodicals; Electronic journals; 547.705
• DOI: 10.1016/j.eurpolymj.2020.110098
• Languages: English
• ISSNs: 0014-3057

Abstract

Graphical abstract: Highlights: Diphenyl phosphate catalyzes the oligomerization of ε-caprolactone and p -dioxanone. Kinetics study discloses a faster rate of incorporation for the p -dioxanone. Well-defined, random co-oligomers with diverse topology are obtained in mild conditions. The acrylated oligomers give soft and pliable polyester networks. Composition and topology determine the bulk properties of the networks. Abstract: We have designed photocurable, telechelic macromonomers consisting of random oligo(ε-caprolactone-co-p-dioxanone), oligo(CL- co -DX), and demonstrated their suitability for preparing pliable polyester networks whose properties resemble those of gels. A versatile and effective metal-free co-oligomerization, catalyzed by diphenyl phosphate, was developed in bulk and at room temperature. A high rate of conversion of monomers was achieved and oligo(CL- co -DX)s with different composition and topology were obtained with controlled molar mass, approx. 2000 g mol −1, low dispersity and a random distribution of the two monomeric units. Kinetics analysis of the reaction disclosed a faster incorporation rate for the p -dioxanone (DX) than ε-caprolactone (CL). The extrapolated rate constant, kDX, was 0.030 min −1 against a kCL of 0.013 min −1 . The reactivity ratios were respectively 2.7 ( r DX ) and 0.28 ( r CL ). A detailed NMR analysis was performed to elucidate the structure of the co-oligomers, which could be precisely controlled by varying the monomer feed ratio and initiator. Depending on the composition, amorphous to semicrystalline oligomers with melting points close to room temperature were obtained, which after acrylation of the chain-end gave polyester networks with high swelling capacity up to 700%, and water uptake up to 70%.