Designing Carbon Fiber Composite Interfaces: Reactive Sizing Derived from Terpenes

Abstract

Terpenes, typically obtained from conifer plants, were chemically modified to include functional groups that could react with both the surface of carbon fiber and the surrounding epoxy resin. This strategy was coupled with the installation of reactive amines (NH2) and thiols (SH) on the fiber surface to specifically react with these sizings. Increases in interfacial shear strength (IFSS) up to 195% were observed for fibers coated in these reactive sizings in combination with the tailored surface chemistry. Improvements in IFSS were also observed for unmodified fibers, suggesting passive functionalization. The presence of persistent carbon-centered radicals was proposed as a way that the fiber surface could react with the sizing agents, stabilized by the inherent high degree of conjugation present within the fiber structure. Interrogating commercially available carbon fiber via electron paramagnetic resonance (EPR) spectroscopy confirmed the presence of radicals within or on the carbon fiber surface (g-value = 1.9984).

Vapor–Liquid Equilibrium of Monoterpene-Sesquiterpene System Containing Resin Acid

“…Pine resin, a non-wood forest product, is produced commercially from approximately 20 pine species in both planted and natural forests in many developing countries. , The volatile turpentine oil (mainly monoterpene and sesquiterpene) and non-volatile colophony obtained by steam distillation of pine oleoresin have hundreds and thousands of uses in the fields of the fine chemical industry, daily chemical industry, agriculture, and medicine. − α -Pinene and limonene are the major components of the monoterpene. α -Pinene has anti-cancer, anti-oxidation, and anti-bacterial effects .…”