Influence of Nanoclay and Graft Copolymer on the Thermal and Flammability Properties of Poly(lactic acid)/Banana Fiber Biocomposites

Biocomposites of poly(lactic acid) (PLA) reinforced with silane treated banana fiber (SiB) were prepared using melt blending technique. To improve the compatibility, a secondary reinforcing filler (Cloisite 30B (C30B) nanoclay) as well as graft copolymer, poly(lactic acid)-graft-glycidyl methacrylate (PLA-g-GMA) as a compatibilizing agent were incorporated in to PLA/SiB biocomposites. PLA-g-GMA was synthesized by free radical copolymerization of different concentration (10, 15, 20, and 25 wt%) of glycidyl methacrylate (GMA) with PLA and was confirmed by Fourier transform infrared spectroscopy spectroscopy and titration method. The influence of C30B nanoclay as well as PLA-g-GMA on the thermal and flammability characteristics of PLA/SiB have been studied. The thermal characteristics of composites have been evaluated by thermogravimetric analysis (TGA). The activation energy of the composites has been estimated using Friedman, Kissinger, and Flynn-Wall-Ozawa (FWO) methods by employing TGA. The obtained activation energy revealed that PLA-g-GMA compatibilized bionanocomposites had better thermal stability. Furthermore, flammability properties were obtained from UL-94 horizontal burning test and cone calorimetry showed enhancement of flame retardant properties after addition of C30B and PLA-g-GMA. J. VINYL ADDIT. TECHNOL., 23:E81-E91, 2017. (c) 2016 Society of Plastics Engineers