Development of jute/coir hybrid natural FRPs for building and automotive thermal insulation: Effect of fiber loading

The present study aims to utilize the unused or waste natural fibers, such as jute and coir fibers, to reinforce an epoxy matrix for the development of hybrid insulation panels intended for building and automotive applications. The hybrid composites were fabricated by combining short jute and coir fibers with epoxy resin using the hand layup method. Prior to fabrication, the raw fibers were treated with an alkali solution to improve fiber-matrix adhesion. The jute and coir fibers were used in equal proportions (1:1 ratio), and the total fiber content in the composites was varied at 0% (neat epoxy or control sample), 10%, 15%, and 20% by weight. The fabricated hybrid composites were characterized by mechanical testing, water uptake, FTIR, thermogravimetric analyzer (TGA), and scanning electron microscope (SEM) test. Mechanical testing revealed a gradual increase in tensile strength (TS), tensile modulus (TM), and impact strength (IS) with increasing fiber content. The composite with 20% fiber loading exhibited the highest improvements, with TS, TM, and IS increasing by 67%, 44%, and 220%, respectively. Water absorption also increased with the increase in fibre loading in the composites. The thermal conductivity test reveals that the composites with 20% fibre loading exhibit the lowest thermal conductivity value of 0.21 W/m.K, highlighting the material's strong potential for insulation applications in the building and automotive industries. • The study focuses on the waste management of inexpensive and short natural fibers for value-added applications in the building and automotive industries as insulating materials. • The mechanical properties improved significantly in the 20% fiber-loaded jute/coir/epoxy hybrid composites compared to the control epoxy sample. • Increased water uptake exhibited for natural fiber loaded hybrid composite structures due to the hydrophilic nature of the natural fibers and the presence of voids and porosity. • The thermal conductivity of the hybrid composites decreased with increasing fiber content due to the non-conductive nature of the natural fibers.