Reinforcement of jute fiber and aluminum trihydrate in a novel biopolymer synthesized through citric acid and glycerol (polyglycerol citrate)

A novel thermoset biopolymer was developed from citric acid and glycerol (referred to as Polyglycerol citrate (PGC)) through polycondensation. PGC is a completely biodegradable and water-soluble polymer, but it has poor thermal stability, fire retardant and mechanical properties. To enhance the usability of this material in food packaging, insulations, and other domestic products, its strength was enhanced by reinforcement through jute fiber (JF) which is also biodegradable and environmentally friendly. The thermal stability and fire-retardant properties of the jute/PGC composite were improved by incorporating aluminum trihydride (ATH) particles in it. The concentration of ATH was varied between 0% and 12% to evaluate the optimum composition for improved thermal, mechanical and flammability properties. The strength and modulus of the material were evaluated using a tensile test while the fire retardant and thermal properties were determined using burning tests, cone calorimetry and thermogravimetric analysis. The surface morphology was studied through a scanning electron microscope. The maximum tensile strength was obtained by incorporating 9% ATH in the jute/PGC composite, which is 236% higher than the strength of neat PGC resin. Similarly, the heat release rate of jute/PGC composite was reduced by 17% with the incorporation of ATH particles. Also, the burning rate of jute/PGC was reduced by 72%. Thermal stability was also observed to improve. Possible chemical interaction between the constituents of the composite was confirmed through Fourier transform infrared spectroscopy (FTIR). The biodegradation of the composite specimens was validated through a soil burial test. Highlights: A novel biopolymer (PGC) was synthesized using citric acid and glycerol. PGC was reinforced with jute fiber to enhance its mechanical properties. ATH was added into the PGC/jute composite to improve its thermal stability. Jute and ATH have O-H interaction with the constituents of the PGC resin. The jute/ATH/PGC composites are biodegradable and non-toxic.