Xie Xiwei, Zhang Caili, Weng Yunxuan, Diao Xiaoqian, Song Xinyu
School of Materials and Mechanical Engineering, Beijing Technology& Business University, Beijing 100048, China.
Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics, Beijing Technology and Business University, Beijing 100048, China.
Materials (Basel). 2020 Feb 10;13(3):806. doi: 10.3390/ma13030806.
Due to the hydrophobic nature of poly (butylene terephthalate) (PBAT), and the hydrophilic nature of bamboo flour (BF), a BF/PBAT (50/50) blend shows low mechanical properties, and especially shows poor impact strength. In order to increase the interfacial adhesion between BF and PBAT, diisocyanate was used as a reactive compatibilizer to modify bamboo powder. A series of BF/PBAT composites were prepared by the method of mixing and melting in an internal mixer. After adding reactive compatibilizer 4,4'-methylenebis(phenyl isocyanate) (MDI), BF/PBAT (50/50) composites with high mechanical properties were successfully prepared. The tensile strength, elongation at break, and impact strength of the BF/MDI-2/PBAT composite with 2 wt % MDI content were increased by 1.9, 6.8, and 4.3 times respectively over the BF/PBAT blend without the added MDI. The higher toughening effect of MDI in BF/PBAT composites can be mainly ascribed to the improved interface bonding between BF and PBAT. The isocyanate group of MDI can react with the hydroxyl group on the BF surface and in situ formation of the carbamate group on the BF surface. The residual isocyanate can then react with the hydroxyl group of PBAT and form carbamate groups. The rheological behaviors demonstrate that addition of appropriate amounts of MDI, 1 wt % and 2 wt %, can promote the flowability of the molten BF/PBAT composites due to the decrease in interparticle interaction between bamboo powder and the increase in the thermal motion of the molecules.
由于聚对苯二甲酸丁二醇酯（PBAT）的疏水性以及竹粉（BF）的亲水性，BF/PBAT（50/50）共混物表现出较低的机械性能，尤其是冲击强度较差。为了提高BF与PBAT之间的界面附着力，使用二异氰酸酯作为反应性增容剂对竹粉进行改性。通过在密炼机中混合熔融的方法制备了一系列BF/PBAT复合材料。添加反应性增容剂4,4'-亚甲基双（苯基异氰酸酯）（MDI）后，成功制备出具有高机械性能的BF/PBAT（50/50）复合材料。MDI含量为2 wt%的BF/MDI-2/PBAT复合材料的拉伸强度、断裂伸长率和冲击强度分别比未添加MDI的BF/PBAT共混物提高了1.9倍、6.8倍和4.3倍。MDI在BF/PBAT复合材料中较高的增韧效果主要归因于BF与PBAT之间界面结合的改善。MDI的异氰酸酯基团可与BF表面的羟基反应，在BF表面原位形成氨基甲酸酯基团。残余的异氰酸酯随后可与PBAT的羟基反应并形成氨基甲酸酯基团。流变行为表明，添加适量的MDI（1 wt%和2 wt%）可促进熔融BF/PBAT复合材料的流动性，这是由于竹粉颗粒间相互作用的降低以及分子热运动的增加。
