Core-Shell Copolymer as Highly Effective Additive for Epoxy Adhesives\

Abstract

A core-shell structured copolymer (CSP) that consists of a rubbery core and an epoxy-miscible shell was synthesized and used as additives in the epoxy resin. The poly(butylacrylate) (PBA) core functions as a rubbery particle that induces the nanocavitation effect, while the poly(ethylene glycol) (PEG) shell allows uniform dispersion within the epoxy resin due to its miscibility with epoxy. A divinylbenzene (DVB) crosslinker was used to bind the core and to synthesize a stable CSP. The mechanical properties of the additive-modified epoxy resin were investigated by measuring the adhesion strength using a universal testing machine. When using CSP as additives in the epoxy resin, the adhesion strength was increased by 160%, while the linear copolymer (LP) only showed a 130% increase. The morphology of the CSPmodified epoxy and the fracture surface morphologies confirm the role of the nanocavitation effect and the void formation in improving the mechanical properties of the CSP-modified epoxy resins.