ABA Block Copolyester Thiol–Ene Resin From Triethylborane-Assisted Ring-Opening Copolymerization

Abstract

Leveraging metal-free ring-opening copolymerization catalyzed by a triethylborane and phosphazene base, we have developed a cytocompatible, thiol−ene-based block copolyester photoresin (BC1) with an ABA triblock architecture. A sebacatederived polyester acting as the chain transfer agent improves the scalability of ring-opening copolymerization and enables the direct, facile synthesis of functional sebacate-derived polyesters by circumventing the conventional high-temperature polycondensation that will often destroy reactive functional groups. BC1's ABA block copolymer design enables tunable elasticity, and its surface property supports the proliferation of human umbilical vein endothelial cells better than polycaprolactone, a polyester with a well-established safety record. The polymerization approach presented in this work expands the potential of sebacate-derived materials and will inspire the development of more elastic photoresins that incorporate safe, renewable, and affordable feedstocks such as sebacic acid and other long-chain aliphatic carboxylic acids.

Advanced Biomaterials for 3D Printing via a Synergistic Dual-Photopolymer Design

“…To tackle this issue, different strategies have been attempted to develop mechanically advanced degradable biomaterials for vat photopolymerization, such as the synthesis of star photopolymers, , the introduction of extra linkages, , side group engineering, the preparation of block photopolymers, , stereochemistry control and thiol–ene chemistry, − and dispersity control . Most recently, a dual-photopolymer formulation approach has emerged as a straightforward strategy for 3D-printing tough and elastic biomaterials. ,− Based on the combination of a longer polymer and a shorter polymer, robust bimodal networks can be formed, benefiting from high chain flexibility from the former and high cross-linking ability from the latter (Figure ).…”

Norbornene Dicarboximide: A Green Alternative for Thiol-Norbornene Photopolymers

“…Thiol-norbornene photopolymers are excellent for vat photopolymerization due to their facile click chemistry. , Nevertheless, their 3D-printing is mainly limited to hydrogels that comprise norbornene-functionalized gelatin, hyaluronic acid, methylcellulose, and chitosan. , An exception is 4Degra, a 3D-printable photopolymer that comprises polycarbonate with pendant norbornenes . In addition, we recently reported a 3D-printable triblock copolyester comprising norbornene repeating units . Nevertheless, thiol-norbornene photopolymers are difficult to scale because their synthesis uses toxic coupling agents, laborious purification, and, in some cases, moisture-sensitive catalysts.…”