High-performance structural linear low-density polyethylene/ Saccharum munja composite: a "design-of-experiments" approach

Natural fiber-reinforced composites are eco-friendly substitutes for synthetic polymers because they are economic, non-toxic and naturally abundant. Saccharum munja is a grass fiber and has the potential as a reinforcement agent in polymer matrix-like linear low-density polyethylene (LLDPE). The composition of the composite system containing LLDPE (from 89 to 55%), munja fiber (from 10 to 40%) and compatibilizer maleic anhydride-grafted linear low-density polyethylene (MALLDPE) (from 1 to 5%) was varied. The experiment was carried out using full factorial design (4 × 3) and composites are studied for their ultimate tensile strength, tensile modulus, flexural strength, flexural modulus, density and thermal stability. The mechanical performance is analyzed by “mixture design analysis”. The optimization was done by the desirability index method and the optimized composition is composed of 57.67% LLDPE, 39.43% munja fiber and 2.9% of MALLDPE. The composite desirability index value for the optimized composite is 0.830. The performance indices of this composite are higher than those of neat polymer, which implies that the composite is light, stiff and strong. The obtained composites are thermally stable at 270 ℃ and the thermal stability of composites with 3% MALLDPE was found to be higher than composites with 1% and 5% MALLDPE. Hence, these composites can be used in making toys, window frames, door frames, cabinets and other structural applications. Graphical abstract