Reactive Butadiene/Acrylonitrile Liquid and Solid Elastomers: A Bibliography for Formulating Epoxy Structural Adhesives

Abstract

Epoxy structural adhesives using carboxylic polybutadiene/acrylonitrile solid and liquid elastomers as modifiers have increased in number and use since their introduction mid-1960. The authors reviewed this subject through early years of development and commercialization (SAMPE Quarterly, 6, No. 4, July, 1975). These ‘epoxy-nitrile’ adhesives were largely supported or unsupported films for metal/metal bonding in aircraft. Since 1974, elastomer toughening and flexibilization has benefited epoxy structural adhesive technology as it proliferated and broadened to embrace electrical/electronics, automotive and industrial applications. Each area requires structural adhesives with balanced shear and peel strengths, excellent vibration/impact resistances as well as environmental durability. ‘Epoxy-nitrile’ adhesives meet these demands while functioning with a wide variety of substrates including prepared and oily metals, rigid plastics, ceramics and glass. More recently, amine-reactive butadiene/acrylonitr ile liquid polymers were developed for two-part epoxy structural adhesives curing under ambient or mildly elevated temperature conditions. The present paper pivots from the 1975 review article and proceeds to cover journal and patent literature since that time. Of concern are preparation of the ‘epoxy-nitrile’ formulating base, elevated- and room-temperature cure systems, structural adhesive testing highlights as well as characterization by morphology, fracture toughness, viscoelastic effects, durability and failure mechanisms. Data exist for both the adhesive bulk and the adhesive joint.