Mechanical and thermal characterization of sustainable Murraya koenigii/Syzygium cumini reinforced polymer hybrid composites

Abstract

The use of organic fiber-reinforced polymer composites is growing fast owing to their sustainable, low-density, and eco-friendly nature. The present investigation was carried out to study the mechanical and thermal properties of hybrid epoxy composites reinforced with Murraya koenigii ( M. koenigii) fibers and filled with Syzygium cumini (S. cumini) bio-filler. The composites were prepared by the hand lay-up method with 0, 1, 2, 4, and 6 wt.% S. cumini filler, and the effect of untreated and alkali-treated fibers was studied. Mechanical characterization was carried out by tensile, flexural, impact, and hardness tests (ASTM standards), while thermal behavior was studied by thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The results indicated that composites containing 4 wt.% S. cumini filler showed optimum performance with alkali treatment, due to improved interfacial bonding between the fiber, filler, and epoxy matrix. TGA results showed improved thermal stability, with a higher degradation onset temperature and char yield, while DMA showed a higher storage modulus and a higher glass transition temperature ( T g ). However, the properties decreased when the filler loading exceeded 4 wt.% due to filler agglomeration and poor dispersion. The results showed that the performance of the composites can be significantly improved through fiber treatment and the optimal incorporation of S. cumini bio-filler, making them promising candidates for sustainable lightweight structural and semi-structural applications.