Mechanical performance of various nylon 6 composites formed by in‐situ polymerization of caprolactam

Abstract This paper describes the fabrication and mechanical characterization of composites made by incorporating various types of glass as bead or fiber into an activated caprolactam melt, which is then caused to anionically polymerize to a nylon 6 resin. Three types of composites are discussed and compared under separate headings: glass bead filled, sheet reinforced with a random fiberglass mat, and sheet reinforced with a unidirectional fiberglass mat that is studied under transverse loading to emphasize the role of the nylon 6 matrix resin. High molecular weight, better wet‐out and adhesion to the reinforcement, and cold drawing of the polycaprolactam resin lead to homogeneous cavitation that increases composite toughness in comparison to epoxy or other nylon matrices of equivalent stiffness.