Compatibilization of biocomposites based on sponge-gourd natural fiber reinforced poly(lactic acid)

To prepare fully biodegradable materials, variable concentrations of luffa fiber (LF) namely 1, 3, and 5 phr, were incorporated into a poly(lactic acid) (PLA) matrix. To counteract the poor adhesion of the LF to PLA, a compatibilizer which is maleic anhydride-grafted poly(lactic acid) has been incorporated and the properties of the composites with and without compatibilizer noted, respectively, PLA/LF and PLA/PLA-g-maleic anhydride (MA)/LF, were compared. The final torque of PLA/LF was found to decrease with the LF content contrary to that of PLA/PLA-g-MA/LF composite which was seen to increase as a result of the interfacial reaction occurring between maleic anhydride groups of the compatibilizer and the hydroxyls of LF. This outcome has been evidenced from the Fourier transform infrared spectroscopy which pointed out the disappearance of the vibration band owing to the anhydride groups of the compatibilizer from the spectra of the PLA/PLA-g-MA/LF composite and the better impregnation of LF by the matrix as it has been observed from scanning electron microscopy. Subsequently, the Izod impact strength of the compatibilized composites was seen to increase, especially for 1 phr of LF, whereas the water uptake aptitude was considerably reduced. Also, PLA phase into the composites exhibited lower thermal stability and glass transition temperature compared to pristine PLA.