Study On Toughening And Reinforcing Modification Of Poly (Lactic Acid)

With the declining of oil storage, the alternative of oil is imperative. Polylactic acid (PLA) can be a better choice for its short time to recycle, but the PLA itself is weak in toughness. In this paper we used SEBS (polystyrene-ethylene-butylene-polystyrene) and SEBS-g-MAH (maleic anhydride grafted polystyrene-ethylene-butylene-styrene) to toughen PLA with melt blending, and the blends show good mechanical properties. It was shown that the blends with SEBS were good at shape memory effect in the experience. The glass fiber were used to strengthen PLA, and they were manufactured by knitting machine as compound fabric.The elongation at break increased extremely with SEBS-g-MAH addition. The impact strength of the samples with the content of 5% and 20% SEBS-g-MAH increases obviously. The elongation at break with 5% SEBS was multiplied by 35 times than the pure PLA, and it increased extremely with SEBS addition.We study on the shape memory effect of the two thougthening composites after forced high-elastic deformation in low temperature. It is tested about the shape memory behavior in different elastomer contents, temperature, elongation and cycle numbers. The shape fixed rate rose while the elongation grew for the blends with SEBS; the shape fixed rate of the blends with SEBS-g-MAH didn’t vary. The tensile strength recovery rate for the two composites remained unchanged when the samples were stretched for 3 times; the tensile strength recovery rate of composites with SEBS was 90%, and the composites with SEBS-g-MAH was 85%. The recovery time varied obviously when the temperature was ranged from 60 to 70℃.When the temperature is up to 70℃, the recovery time won’t change much for all the composites. In this paper, we adopt GF/PLA as complex yarns in order to make GF/PLA composite. The mechanical properties of the composites were better when the samples were pre-stretched. The tensile strengthen is higher in the 90°direction than the 0°. The PLA will degradation during the making process, which weaken the tensile strengthen. In the SEM images, the GF is well dipped in the resin.