Degradation of PLA Biocomposites Containing Mango Seed and Organo Montmorillonite Minerals

The research of polylactic acid (PLA) packaging materials with high degradation rate is important toward high rate biodegradable packaging materials. The samples (PLA-mango seed residue-clays) were evaluated by degradation analysis (in water and in soil) followed by FTIR, NMR, SEM/EDS and Texturometer analysis. The samples degradation was more effective in water than in soil, probably due to a coupled effect of water and microbiological degradation. PLA-kernel-tegument samples degraded more than PLA-kernel samples due to the effectiveness action of kernel and tegument together in the samples' degradation. PLA-Bofe samples degraded less than PLA-kernel-tegument and PLA-kernel-tegument-Bofe samples, PLA-Chocolate clay (Bofe and Chocolate are organo-montmorillonite clays) samples degraded more than PLA-kernel-tegument-Chocolate samples and less than PLA-kernel-tegument samples, probably due to multiples interaction among the Chocolate clay and mango components. The FTIR bands after samples hydrolytic and soil degradation presented low intensity, probably indicating materials degradation. New bands were observed after soil degradation, most likely related to accumulated soil and band displacement, indicative of samples degradation. The NMR relaxation data confirm the degradation process observed form the other techniques, observing the changes in the values of proton relaxation data for all samples, comparing the values after and before been degraded.