Vapor Grown Carbon Fiber/Polydicyclopentadiene Composites: Shapeable Pastes to Make Composite Tooling and Plasma Erosion-Resistant Parts

摘要

Vapor grown carbon nanofibers (VGCF) with 60-250nm diameters and 10 to 80 micrometers lengths were blended with the nonpolar organic monomer, dicyclopentadiene, to create liquid dispersions or pastes (based on the wt% fiber used). Ruthenium catalysts were mixed in to cause ring-opening methathesis polymerization, generating tough crosslinked resin matrics reinforced by the nanofibers. In addition to dicyclopentadiene, other liquid resins, including phenolic, epoxies and vinyl esters were also blended with these nanofibers and then cured to form organic matrix carbon fiber composites. When the wt% fiber was sufficient, shapeable pastes could be made, molded and cured. Fluid mixtures could be coated onto surfaces and cured. The dynamic mechanical and mechanical properties and in some cases high temperature erosion resistant properties and electrical properties of the cured composites were measured. VGCF, when blended with EPDA resins, were shown (joint work with S. Phillips et. al. Edwards AFB) to be superb materials for rocket liners in solid propellant motors due high temp. erosion resistance. VGCF-phenolic resins exhibited excellent high temp. ablation resistances in (caret)1600 degrees C plasma torch tests, due in part to the short heat transfer lengths of these tiny fibers. As this work proceeded, efforts were broadened to incorporate polyhedral oligomeric silsesquioxane (POSS) nanophases into resins to form oxidation barriers and improve thermal properties. Multifunctional and monofunctional POSS derivatives were incorporated into many resin systems and studies of nanoaggregation were undertaken.