Degassing and layers variation effect on composite processing by vacuum assisted resin transfer moulding

Abstract

Vacuum assisted resin transfer molding (VARTM) is a fiber reinforced composite (FRC) making process in which resin is impregnated to fabric by application of vacuum. The critical issue in VARTM process is void generation. Voids form due to variety of reasons, most of which can be avoided. The primary cause for void formation is air entrapment during impregnation. Air may generate at resin and hardener mixing stage, during exothermic reaction, due to leakage in vacuum bag, during initial supply, by temperature increase or due to residual air inside the fabric. Due to application of vacuum and pre-compaction most of air will get escape. Vacuum degassing is one of the solutions which will reduce air entrapped inside resin during impregnation. In this work six laminates from jute and polyester resin were prepared, three with degassing and three without degassing with variation in number of jute layers 5, 10 and 15 respectively. Microscopic examination and mechanical properties have been observed before and after degassing. It was observed that degassing improves mechanical properties of composite laminates and reduce void content. The thickness variation in laminate after curing was performed, and it was observed that the thickness variation increased as number of layer increased.