Flexural and shear strength properties of unidirectional carbon fiber reinforced polymer composite interleaved with recycled carbon fiber and short virgin aramid fiber non-woven mats

Abstract

Carbon fiber reinforced polymer composites (CFRPs) are one of the most widely used composite types and wastes associated with them (CFRPs) get generated through either their manufacturing or end-of-service-life. Predominately due to environmental concerns and governmental regulations, recycling these CFRPs is needed and to make use of the recycled carbon fibers (rCFs), a wet paper-making technique was used to convert the rCFs into a 60 g/m 2 non-woven mat. For comparison purposes, the same technique was used to convert short virgin aramid fibers (vAFs) into a 60 g/m 2 non-woven mat. Each mat was sandwiched with two resin films and then interleaved with 12-ply unidirectional (UD) prepreg tapes (carbon/epoxy). The assemblage was molded into composite laminates using a vacuum bagging assisted compression molding technique, and the samples for the tests were cut using a waterjet machine accordingly. Compared with the control, the results indicate an increment in the flexural modulus, and the specific flexural modulus for the CFRPs with non-woven mats: the flexural modulus increased by approximately 8.2% and 12.0% for the CFRP with rCF and vAF mats, respectively; the specific flexural modulus increased around 9.5% and 13.3%, respectively for the CFRP with rCF and vAF mats. On the other hand, the shear strength approximately decreased by 6.4% and 6.0% for the CFRP with rCF and vAF mats, respectively. The negative shear strength performances of the composite laminates with non-woven mats reflected on their flexural strength performances: the flexural strength increased about 1.1% and decreased by approximately 7.9% for the CFRP with vAF and rCF mats, respectively. To resolve the negative shear strength performances, it is recommended that the surfaces of the mats be treated with a coupling agent to improve their interfacial adhesions.