Co-Injection Resin Transfer Molding of Vinyl-Ester and Phenolic Composites

摘要

Vacuum-assisted resin transfer molding (VARTM)-type processes have been proven cost-effective manufacturing techniques for large composite structures. However, their use has been limited to a single resin system. Many composite structures require multiple resins to serve different purposes while being integrated into a single structure. Co-injection resin transfer molding (CIRTM) is a new manufacturing process developed by the U.S. Army Research Laboratory (ARL) with the University of Delaware that enables the user to manufacture multilayer hybrid composite parts in a single processing step. In this report, CIRTM is used to manufacture a dual-layered structure consisting of a vinyl-ester layer for structural integrity and a phenolic layer for fire, smoke, and toxicity protection. The two resins are simultaneously injected into a mold filled with a stationary fiber bed and are co-cured. Resin separation is maintained by a 1-mil-thick polysulfone film sandwiched between two layers of 6. 5-mil-thick adhesive. A differential scanning calorimeter (DSC) is used to select the optimum cure cycle for all of the materials. Mechanical testing is used to evaluate the performance of the interphase formed between dissimilar materials. Experimental results show that co-injected, co-cured materials offer equivalent properties or, in some cases, more superior properties, than those provided by single-injection resin composites. This case is used to develop and present a methodology that can be followed to co-inject different resins.