Department of Chemical and Biotechnological Engineering, Université de Sherbrooke, 2500 boulevard de l'Université, Sherbrooke, QC, Canada.
Department of Chemical Engineering, Centre de recherche sur les systèmes polymères et composites (CREPEC), Polytechnique Montréal, 2500 chemin de Polytechnique, Montréal, QC, Canada.
Carbohydr Polym. 2019 Feb 15;206:757-766. doi: 10.1016/j.carbpol.2018.11.038. Epub 2018 Nov 13.
This study focuses on the morphology development in blends of thermoplastic starch (TPS) with Low Density Polyethylene (LDPE) in the 40 to 80 TPS wt% concentration range. The effect of glycerol and water content on TPS rheology and the subsequent morphology development after blending with LDPE of various viscosity levels was investigated. The TPS/LDPE viscosity ratio was modified either by increasing the TPS plasticization or by proper selection of the LDPE grade. Particular attention was given to the effect of TPS humidity on viscosity and therefore humidity levels were carefully measured by Karl Fisher titration prior to rheometry. It was found that the viscosity of the TPS was highly dependent on the plasticizer level and that the flow activation energy of TPS was around 3 times higher than that of LDPE. Different types of blend morphologies were achieved from dispersed to co-continuous. It was found that the co-continuous structure appeared at higher TPS concentration when increasing the TPS/LDPE viscosity ratio.
本研究集中于热塑性淀粉（TPS）与低密度聚乙烯（LDPE）在 40 至 80 TPSwt%浓度范围内的共混物中的形态发展。研究了甘油和水分含量对 TPS 流变性的影响，以及在与不同粘度水平的 LDPE 共混后形态发展的后续情况。通过增加 TPS 的增塑作用或适当选择 LDPE 等级来改变 TPS/LDPE 的粘度比。特别关注 TPS 湿度对粘度的影响，因此在流变学测试之前，通过卡尔费休滴定法仔细测量了湿度水平。结果发现，TPS 的粘度高度依赖于增塑剂水平，并且 TPS 的流动活化能大约是 LDPE 的 3 倍。从分散到共连续，实现了不同类型的共混形态。结果发现，当增加 TPS/LDPE 的粘度比时，共连续结构出现在更高的 TPS 浓度下。
