Synthesis and Characterization of Epoxy-Methacrylate Bisphenolic Resin for Thermoset Applications and Additive Manufacturing

摘要

Monomers functionalized with two different polymerizable groups are highly valuable due to their versatile nature in manufacturing. In general, (meth)acrylic resins have desired photo and thermal reactivity but lead to shrinkage after curing; whereas epoxy resins have significantly less volume changes upon curing but are less sensitive to light [1]. Interpenetrating polymer networks synthesized by crosslinking polymerizations of dual functional monomers combine properties of both chemistries, and are expected to yield a harder and more resistant material due to their expected, higher crosslink densities [2]. Our goal was to synthesize and characterize bisphenolic dual functional monomers and polymers to investigate their structure-property relationships via spectroscopic, thermal and mechanical methods. We partially methacrylated diglycidyl ether of bisphenol A (DEGEBA) to produce a dual functional resin (EEW= 492, MnNMR= 481.3±6.4 g/mol), then we added styrene, and both cationic and free radical initiators for thermal cure. Extent of cures obtained by FT-NIR were ? 97.8 % and ? 98.7% for vinyl and epoxy groups, respectively. Viscosity of formulations ranged from 58.3 Pa s to 116.5 Pa.s at 25 C. Initial decomposition temperature of thermosets were ? 334.8 ± 8.7 C in air and ? 344.9 ± 1.4 C in N2. We also evaluated the feasibility of using such resins in hybrid additive manufacturing processes to eventually compare properties of 3D-printed thermosets to that of traditionally cured polymers. Results support the hypothesis that monomer dual-functionality influence the ultimate characteristics of the polymers. Diversification of crosslinking patterns provides more flexibility for formulating and manufacturing, leading to novel materials with hybrid properties and a plethora of potential original applications.