关键词: 聚乳酸, 乙烯-乙酸乙烯酯共聚物, 共混, 熔体流动速率, 结晶, 黏度

Abstract: Poly(lactic acid)（PLA）/poly(ethylene-co-vinyl acetate)（EVA） blends were prepared by melt blending. The effects of melt flow rate of EVA （28% VA content） on the morphology，thermal properties and rheological behaviors of PLA/EVA blends were investigated. The results indicated that the EVA phase with smaller particles and better dispersion in the PLA matrix was observed when the EVA with lower melt flow rate was used. With the increase of melt flow rate of EVA，the crystallinity of blends was increased，though the Tg of PLA was hardly affected by the addition of EVA. And the complex viscosity and storage modulus of the blends were decreased. It was demonstrated by mechanical tests that with the addition of 15% EVA into PLA，an obvious increase in elongation at break was observed，and the izod notched impact strength was about two times higher than the pure PLA.

Key words: poly(lactic acid), ethylene-co-vinyl acetate, blend, melt flow rate, crystallization, visicosity