Cocoon waste reinforced in epoxy matrix composite: Investigation on tensile properties and surface morphology

Abstract

There is potential for using silkworm cocoon waste such as broken, damaged, discarded and uncoiled cocoons as well as the caterpillars that remain inside. Cocoon waste is estimated to account for up to 11% of raw cocoon input in the textile industry. The aim of the present work is to use cocoon waste as the natural fiber reinforcement in an epoxy resin matrix composite. Cocoon waste with different weight fractions of 0 wt%, 25 wt%, 42 wt%, 58 wt%, and 75 wt% were used as reinforcement with an epoxy resin matrix to fabricate the composite material by hand lay-up technique. Subsequently, tensile testing and scanning electron microscopy observations were employed to evaluate the performance of the proposed composite materials. Experimental results demonstrated that the tensile strength continuously increased as cocoon waste fiber increased from 25 wt% to 58 wt%, reaching a maximum tensile strength of 61.04 MPa. Elastic modulus showed a slight difference of 25 wt% to 58 wt%, a maximum of 762.91 MPa. However, at 75 wt%, the tensile strength and elastic modulus declined by 57.07 MPa and 515.69 MPa, respectively. The 58 wt% of cocoon waste was presented as the optimum ratio for reinforcement with an epoxy resin matrix. The SEM image revealed the dispersion of cocoon waste in an epoxy resin matrix, presenting the close-packed interfacial bonding between cocoon waste fiber and matrix. This research is useful for the development of cocoon waste-based composites with improved mechanical properties.