Structure and properties of poly(p‐xylylene) composites made by electrochemical and vapor deposition polymerization

Abstract Poly(para‐xylylene)(PPX)/carbon fiber towpregs were produced by two different in‐situ polymerization processes: Electrochemcal polymerization (ECP) and vapor deposition polymerization (VDP). The monomer used for the ECP process was α, α′ ‐dibromo‐para‐xylylene and di‐para‐xylylene was the starting material for the VDP process. A series of tests, including FTIR, WAXD, DSC, TG, and SEM were carried out to identify and compare these two composite towpregs. It has been confirmed that the PPX samples obtained by the two different polymerization processes were basically chemically identical. However, the polymer coating on the fiber surface produced by the VDP process was much smoother than that produced by the ECP process, which produced a porous coating.