PVA／淀粉薄膜挤出吹塑工艺及性能研究

The Technology of PVA/Starch Bubble Film

采用挤出造粒和吹塑工艺连续制备了聚乙烯醇／淀粉薄膜。探讨了淀粉含量、增塑剂含量、增塑剂中水含量和混料条件对PVA／淀粉薄膜加工温度、熔体流动性和薄膜力学性能的影响。结果表明，随着淀粉含量的增加，增塑剂含量的增加，物料的加工温度降低；随着增塑剂中水含量的增加，挤出造粒温度升高，吹膜温度不变；PVA／淀粉共混物优选的造粒温度是165～180℃，吹膜温度是205—220℃；淀粉含量为35％～50％，增塑剂含量60份以上，增塑剂中的水含量为1／6～1／3时，共混物有较好的加工流动性；分批逐滴加入增塑剂并在80～110℃下混料，可以使PVA／淀粉充分溶胀，利于热塑性加工；淀粉含量为40％、增塑剂含量为60份、增塑剂中的水含量为33％时，薄膜力学性能最佳。

PVA/Starch films were continuously prepared by pelleting and bubble film technology. Effects of starch content, plasticizer content, ratio of water/plasticizer and mixing condition on processing temperature, melt fluidity and mechanical properties were investigated. It was found that processing temperature was reduced with the increment of starch and plasticizer content, the pelleting temperature increased and the bubble film temperature did not change apparently with the increment of water/plasticizer. The optimal pelleting temperature was from 165℃ to 180℃ and optimal bubble film temperature was from 205℃to 220℃. Melt fluidity was better when starch content changed from 35% to 50% ,plasticizer content was beyond 60 phr and ratio of water/plasticizer was from 1/6 to 1/3. PVA/Starch blend would be well swelled and plasticized if the plasticizer was added in gradually and components were mixed between 80℃and 1l0℃. Best mechanical properties were measured when the starch content was 40% ,plasticizer was 60 phr and the water content was 33%.