Federal University of Rio de Janeiro, Department of Materials Science and Engineering, P.O. Box: 68505, 21945-970 Rio de Janeiro, Brazil.
Federal University of Rio de Janeiro, Department of Materials Science and Engineering, P.O. Box: 68505, 21945-970 Rio de Janeiro, Brazil.
Int J Biol Macromol. 2019 Feb 15;123:609-621. doi: 10.1016/j.ijbiomac.2018.11.070. Epub 2018 Nov 14.
The present work aims to study the effect of the addition of poly (hydroxybutyrate) PHB as reinforcement in thermoplastic cornstarch (TPS) produced by the thermal compression molding method. Initially, the physical and chemical properties of TPS with different amounts of glycerol as the plasticizer (25, 30 and 35 wt%), are evaluated. Then, the composites, including 35% glycerol and different PHB contents (10, 20 and 30 wt%), are prepared. Additionally, the surface of the PHB granules is modified by plasma treatment using atmospheric air and sulfur hexafluoride (SF) gas. In order to evaluate the influence of the PHB contents before and after the plasma treatment, the composites are characterized by FTIR, TGA, DSC, XRD, SEM, and mechanical tests. SEM showed a homogeneous distribution of PHB granules in the TPS matrix. On the other hand, the micrographs of the composites, using the high concentration of plasma-treated PHB, showed the agglomerated particles in the starch matrix, which represented stress concentrators, and showed weak interfacial adhesion leading to the poor mechanical properties. The thermogravimetric analysis of the composites with PHB treated by plasma showed a higher thermal stability compared to the composites of TPS and untreated PHB.
本工作旨在研究添加聚羟基丁酸酯（PHB）作为增强剂对热压成型法制备的热塑性玉米淀粉（TPS）的影响。首先，评估了不同甘油含量（25、30 和 35wt%）作为增塑剂的 TPS 的物理和化学性质。然后，制备了包括 35%甘油和不同 PHB 含量（10、20 和 30wt%）的复合材料。此外，通过使用大气压空气和六氟化硫（SF）气体的等离子体处理对 PHB 颗粒的表面进行改性。为了评估等离子体处理前后 PHB 含量的影响，通过傅里叶变换红外光谱（FTIR）、热重分析（TGA）、差示扫描量热法（DSC）、X 射线衍射（XRD）、扫描电子显微镜（SEM）和力学测试对复合材料进行了表征。SEM 显示 PHB 颗粒在 TPS 基体中均匀分布。另一方面，使用高浓度等离子体处理 PHB 的复合材料的微观照片显示，淀粉基体中存在团聚的颗粒，这些颗粒是应力集中点，表现出较弱的界面粘附力，导致力学性能较差。经等离子体处理的 PHB 复合材料的热重分析显示，与 TPS 和未经处理的 PHB 复合材料相比，其热稳定性更高。
