Preparation And Characterization Of Polylactic Acid/Silicon Carbide Nanocomposites

Polylactide(PLA)is a biodegradable thermoplastic aliphatic semicrystalline polyester synthesized from renewable resources such as corn starch,cassava root,and beet sugar.PLA exhibits strength properties similar to some petroleum-based thermoplastics such as polyethylene,polypropylene,polystyrene,and polyethylene terephthalate;therefore,it has been developed as a potential alternative to traditional petroleum-based polymers.In addition,PLA's processing methods are simple and convenient,such as extrusion,injection molding,thermoforming and compression molding.Therefore,PLA is used in packaging,biomedical,industrial vehicle interiors and engineering applications.However,PLA's several shortcomings,such as low impact strength and high price,have limited its wide application.To overcome these limitations,PLAs are usually modified with compatible modifiers,additives,or fillers.Recently,nano-filler reinforced polymer composites have attracted the interest of researchers in academia and industry.These nanocomposites are prepared by dispersing fillers having a few nanometer order into the polymer matrix.Nanoparticles are incorporated into the polymer to form a large number of interfaces and enhance the intermolecular interaction between the filler and the polymer matrix.In this paper,PLA-based composites were prepared by using different coupling agents to modify nano-SiC and blended with PLA solution.The thermal stability,fracture toughness,mechanical properties and morphology of powders and composites were studied.The research results of the paper are as follows:1.Results of silane coupling agent treatment of SiC toughened PLA:With the addition of SiC on the surface of the silane coupling agent,the thermal stability of the composite was slightly lower than that of pure PLA.The fracture toughness and impact strength of PLA/S-SiC composites are significantly higher than that of pure PLA by 18 % and 56 %,respectively.With the addition of modified SiC,both the flexural strength and the flexural modulus of the composites increase first and remain at a stable level.The SEM images show that the impact section of PLA/SiC and PLA/S-SiC composites has a rougher impact fracture surface than pure PLA.2.Titanate coupling agent treatment of SiC toughened PLA research results:With the addition of SiC on the surface of the titanate coupling agent,the thermal stability of the composite was slightly lower than that of pure PLA.Compared with pure PLA,the fracture toughness and impact strength of PLA/SiC composites are significantly higher than those of pure PLA by 52% and 68% respectively.With the addition of modified SiC,both the flexural strength and flexural modulus of the composites increase at first and remain at a stable level.The SEM images show that the impact section of PLA/SiC and PLA/T-SiC composites has a rougher impact fracture surface than pure PLA.