聚乳酸/聚丙烯的共混改性及热学和力学性能

针对聚乳酸力学性能和耐热性差以及聚丙烯生物降解能力差等缺点,将聚乳酸和聚丙烯按照一定比例进行共混,以聚乙二醇为增容剂,采用双螺杆挤出机制备了聚乳酸/聚丙烯共混物,并分析了共混物力学性能和热学性能的变化.结果表明:共混物的结晶温度低于纯聚乳酸;当聚乙二醇的质量分数为9%时,共混物的两相达到完全相容,共混物的热稳定性和韧性得到提高,最大断裂伸长率为纯聚乳酸的3. 7倍,但拉伸强度和弯曲强度下降;共混物的热学和力学性能均优于聚乳酸和聚丙烯.

Blending modification and thermal and mechanical properties of polylactic acid/polypropylene

Aiming at the disadvantage that the polylactic acid(PLA)has poor mechanical properties and thermotolerance and the polypropylene(PP)has poor biodegradability, the PLA and PP were blended according to a certain proportion, the polyethylene glycol(PEG)was taken as the compatibilizer, and the PLA/PP blends were prepared with the double screw extruder. In addition, the changes in the mechanical and thermal properties of blends were analyzed. The results show that the crystallization temperature of blends is lower than that of pure PLA. When the mass fraction of PEG is 9%, two phases of blends reach completely compatible, the thermal stability and toughness of blends get enhanced, and the maximum fracture elongation is as 3.7 times as that of pure PLA, while the tensile strength and bending strength decrease. Furthermore, the thermal and mechanical properties of blends are better than those of PLA and PP.