An investigation about the mechanical properties of the knitted fabric reinforced composites that produced on flat knitting machines

If the researches about the knittability of technical textiles in flat knitting machines done in the past years are investigated, the materials, in which high mechanical properties are not required, are noticed. These materials are medical textiles like bandage and compression hosiery and the fully fashioned materials like T pipes. On the other hand, in recent years, the studies about textile reinforced composites in the area of technical textiles are increased. Great majority of them are knitted on hand knitting machines. An aim of this study is to investigate the knittability of preforms which will be used for textile reinforced composites on industrial rapid flat knitting machines.In this study, glass, flax, cotton and polyester yarns are used to produce spacer knitted fabric performs, in which single and double tuck stitches are used, on industrial type flat knitting machine. After that, the knitted performs are processed with matrix materials to obtain composites. Tensile strength, compression strength and impact strength tests were applied to the composites to determine the mechanical properties.For this aim, firstly, glass yarn, which is very popular in composite reinforcement, and the polyester yarn, which is used very widespread in textile industry is used. The single and double tuck stitched spacer fabric performs which are knitted from glass and polyester yarns are made into thermoset composites with epoxy resin.Later on, ecological composites are studied which gain importance in automobiles that are the leaders in using composites. For this purpose, after the cotton and flax yarns are knitted into single and double tuck stitched spacer performs, they are made into composites with epoxy, vinylester or polylactic acid. The aim of choosing epoxy or vinylester thermoset resins was their common usage. But these resin materials are not biodegradable. For this reason, by using polylactic acid, a 100% recyclable and biodegradable composite is produced and second aim of the study is performed.