Comparison of Mechanical and Flammability Properties of Benzoxazine and Epoxy Resin Based Carbon Fibre Composite Sandwich Structures

摘要

The present study is focused on investigating a potential alternative composite resin for the manufacture of a composite sandwich system with improved mechanical and fire retardant properties for structural applications. Epoxy based resins are commonly used in the automotive, aerospace, defence and space technologies. Epoxy resins are meeting the strength requirements; however, it requires filler additives for improving the flammability behavior. Benzoxazine resin possesses better flammability characteristics than other phenolic resins due to the nature of the formation of a comparable network after polymerization and excellent mechanical properties. This study was mainly focused on comparing the mechanical and flammability characteristics of benzoxazine and epoxy resin based carbon fibre composite sandwich structure that can be suitable for structural applications. For this characterization study, sandwich panels consisting of face sheets (made with bi-directional 2×2 twill of 200 GSM carbon fibers with Anabond Anazine 1951 hot cured hybrid benzoxazine monomer resin and epoxy grade Lapox B11, based on Bisphenol-A with a low viscosity triethylenetetraamine based hardener) and aluminium honeycomb core bonded with a hot cure epoxy film adhesive have been developed. Mechanical properties such as tensile, flexural, edgewise compression and flatwise compression tests were conducted for both benzoxazine and epoxy resin based CFRP composite sandwich structures. In addition to mechanical testing, flammability characteristics of both benzoxazine and epoxy based composite laminates were conducted for UL94 vertical burning classification test. It is observed from the test results that both mechanical and flammability properties were found to be superior in the case of benzoxazine resin based composite system. Thus, it can be concluded that hybrid benzoxazine resin shall be considered as an alternative resin system for structural applications such as aerospace, automotive and defence systems. The details related to the materials, methods, and test outcomes are discussed in this paper.