Effect of moisture content of jute fabric and hybridization structure on the impact properties of jute and jute/glass hybrid composites

A preliminary investigation on the impact properties and morphologies of unsaturated polyester reinforced with jute woven fabric recycled from used coffee bags with different moisture contents was conducted. The laminated structural effect of hybridization with glass woven fabric was also investigated. Jute/jute-laminated composites, and jute/glass/jute- and jute/jute/glass-laminated hybrid composites were fabricated by the hand lay-up method. Their impact properties were compared by drop-weight and the Izod impact tests. The acoustic emission (AE) technique was applied under a tensile load to detect micro-failure processes in the jute and jute/glass hybrid composites. The number of AE signals and the AE energy were monitored using two transducers with resonant frequencies of 140 kHz and 1 MHz. The results showed that the moisture content affected the mechanical properties of the composites. The strength and elongation at break of the jute yarn decreased with a decrease in moisture content. The AE characteristics and observations of the fracture surfaces revealed that the composites fabricated from jute fabric with low moisture content had a relatively higher initial fracture stress and higher resistance to micro-fractures. Moreover, the mechanical properties of the hybrid composites were significantly affected by the laminating structure.