Photopolymerized Triazole‐Based Glassy Polymer Networks with Superior Tensile Toughness. (6th April 2018)

• Record Type: Journal Article
• Authors: Song, Han Byul; Baranek, Austin; Worrell, Brady T.; Cook, Wayne D.; Bowman, Christopher N.
• Is Part Of: Advanced functional materials. Volume 28:Number 22(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-04-06
• Subjects: additive manufacturing -- "click" chemistry -- ductile thermosets -- photopolymerizations -- photopolymers; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201801095
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Photopolymerization is a ubiquitous, indispensable technique widely applied in applications from coatings, inks, and adhesives to thermosetting restorative materials for medical implants, and the fabrication of complex macroscale, microscale, and nanoscale 3D architectures via additive manufacturing. However, due to the brittleness inherent in the dominant acrylate‐based photopolymerized networks, a significant need exists for higher performance resin/oligomer formulations to create tough, defect‐free, mechanically ductile, thermally and chemically resistant, high modulus network polymers with rapid photocuring kinetics. This study presents densely cross‐linked triazole‐based glassy photopolymers capable of achieving preeminent toughness of ≈70 MJ m −3 and 200% strain at ambient temperature, comparable to conventional tough thermoplastics. Formed either via photoinitiated copper(I)‐catalyzed cycloaddition of monomers containing azide and alkyne groups (CuAAC) or via photoinitiated thiol‐ene reactions from monomers containing triazole rings, these triazole‐containing thermosets completely recover their original dimensions and mechanical behavior after repeated deformations of 50% strain in the glassy state over multiple thermal recovery–strain cycles. Abstract : Triazole‐based photopolymer networks with superior toughness and ductility are developed via two independent "click" photochemistry reactions in bulk, demonstrating unprecedented shape‐memory recovery attributes upon large tensile deformation in the glassy state. This superior mechanical performance with "thermoplastic‐like" extensibility of highly cross‐linked thermosetting materials suggests possibility for the use in additive manufacturing.