Abstract: PLA was adopted as a polymeric matrix to prepare PLA/nanoclay composites. The effect of the amount of nanoclay together with 2 phr SiO2 as a hybrid reinforcement on the structures and properties of the composites were investigated. The results indicated that the crystallization behaviors， melt processability， mechanical toughness， and gas barrier property of the PLA composites were significantly improved. The PLA composite with 2 phr SiO2 and 4 phr clay exhibited good filler dispersion， ductile fracture， and good gas barrier property. Compared to pure PLA， the PLA composites presented an increase in elongation at break by 151 % and in impact strength by 74.1 %. Their oxygen and water vapor permeability coefficients were reduced by 67.4 % and 65.0 %， respectively. The excessive amount of clay was disadvantageous to the toughness and also generated a slightly influence on gas barrier.

Key words: polylactic acid(PLA), hybrid reinforcement, mechanical properties, gas barrier property