Carbon fiber surface treatment for improved adhesion and performance of polydicyclopentadiene composites synthesized by ring opening metathesis polymerization
David J. Hayne, Matthew J. Singleton, Brendan A. Patterson, Daniel B. Knorr, Filip Stojcevski, Luke C. Henderson
Abstract
Assessing new polymers for carbon fiber composite applications is critical due to a broadening demand in applications not typical for existing fiber-resin systems. Polydicyclopentadiene, synthesized via Ring Opening Metathesis Polymerization (ROMP), performs exceptionally well in high velocity impact applications, though it is challenging to reinforce with carbon fibers given the unreactive nature of both fiber and resin. In this work, we use a carbon fiber surface modification approach to promote fiber-matrix adhesion via the attachment of small molecules able to participate in the polymerization process. This strategy significantly improved flexural and fracture properties, typically between 15-30%, relative to composites reinforced with unmodified fibers. Similarly, the tensile yield strength and ultimate tensile strength were improved using this surface modification strategy, though a small decrease in tensile modulus was observed (<5%). Imaging the fracture surfaces shows a clear difference in adhesion, with good adhesion noted for the fibres which had undergone surface modification.