Study On Preparation And Properties Of Nutshell/PLA Composites

Polylactic acid (PLA) is a kind of biodegradable polyester with good biocompatibility and mechanical properties. It can be used in medicine, packaging, automotive interiors and furniture and other fields. Completely biodegradable composite prepared by PLA matrix and bio-filler attracts much attention because of the unique advantage in area of agricultural production, home decoration, daily life. As waste of agriculture and forestry productions, pine seed shell (PSS), walnut shell (WS) and other nuts shell, who have low density and plant fiber characteristics, are renewable, biodegradable. Exploring the preparation of polymer matrix composite filled with PSS and WS is of positive significance.Completely biodegradable composite prepared with PSS and WS as fillers and PLA as matrix. Interface effects of PSS and WS filler and PLA matrix was explored. PSS and WS were treated by surface-modification of silane coupling agent, and by coating of acrylic resin. Interface compatibility agent (MA-PLA) was used to improve the interface compatibility between the filler and matrix. Thermal degradation behavior and thermal stability of NS/PLA composites were studied.The content of PSS and WS has a significant impact, mechanical properties of PLA/NS composites was reduced when content of filler was more than5%. Result of FTIR indicated that surface hydroxyl group of PSS and WS filler reacts with silane coupling agent, the mechanical properties and interfacial adhesion between matrix and filler was improved. Interface compatibility agent (MA-PLA) could improve interface property of NS/PLA composite. Result of SEM showed that the different surface structure of PSS and WS made enhancement ratio of PSS/PLA composites sample containing8wt%MA-PLA than WS/PLA composite. PSS and WS acrylic resin coating treatment can enhance the mechanical properties of NS/PLA composites, and the reinforcing ratio of the WS/PLA composite is higher than the PSS/PLA composite. Thermal analysis showed that MA-PLA reduces the thermal stability of the composite material, but the silane coupling agent may increase the thermal stability of the composite material, Tg of composite was decreased as addition of WSP increased. Treatment by Silane coupling agents could increase Tg of Composite with40wt%WS. Result of TG-FTIR indicated that there was no toxic gas released in the decomposition process.