Chen Xinyi, Ding Yitong, Li Mingjiao, Wu Hao, Kan Ze, Li Zhibo
Key Laboratory of Biobased Polymer Materials, Shandong Provincial Education Department, College of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao, China.
Key Laboratory of Biobased Polymer Materials, Shandong Provincial Education Department, College of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao, China.
Carbohydr Polym. 2024 Nov 1;343:122436. doi: 10.1016/j.carbpol.2024.122436. Epub 2024 Jul 1.
Chemically synthesized poly(4-hydroxybutyrate) (P4HB) is a new generation of biomass-derived and degradable semi-crystalline polymer with good comprehensive properties, but high costs limit its application. Starch, as an inexpensive natural polymer, can reduce the cost of P4HB products. However, starch lacks thermoplastic behavior and has poor compatibility with P4HB, thus its extensive use will inevitably impair the mechanical properties of P4HB. In this study, the ball-milling starch grafting process is adopted, which can simultaneously solve the two major deficiencies of starch, and the prepared ball-milling starch-g-polycaprolactone (BSt-g-PCL) has thermoplasticity and better compatibility with P4HB. BSt-g-PCL can melt near 55 °C, and the interweaving of its molecular chains with P4HB reduces the binding energy (E) of both, making the phase interface blurred or even disappear. Therefore, the elongation at break retention (R) of P4HB/BSt-g-PCL can increase from 37.1 % to 74.3 % compared to P4HB/starch at the same filling (70 Phr). Additionally, BSt-g-PCL can exert the effect of accelerating P4HB degradation and still make it maintain excellent anti-aging ability. The ball-milling starch graft process provides a simple and effective method for the preparation of inexpensive fully biodegradable P4HB composite films with excellent mechanical properties.
化学合成聚（4-羟基丁酸酯）（P4HB）是新一代源自生物质的可降解半结晶聚合物，具有良好的综合性能，但高成本限制了其应用。淀粉作为一种廉价的天然聚合物，可以降低P4HB产品的成本。然而，淀粉缺乏热塑性行为，与P4HB的相容性较差，因此其广泛使用将不可避免地损害P4HB的机械性能。在本研究中，采用球磨淀粉接枝工艺，该工艺可以同时解决淀粉的两大缺陷，制备的球磨淀粉接枝聚己内酯（BSt-g-PCL）具有热塑性且与P4HB具有更好的相容性。BSt-g-PCL在55℃左右可熔融，其分子链与P4HB相互交织降低了两者的结合能（E），使相界面模糊甚至消失。因此，在相同填充量（70 phr）下，与P4HB/淀粉相比，P4HB/BSt-g-PCL的断裂伸长率保留率（R）可从37.1%提高到74.3%。此外BSt-g-PCL可以发挥加速P4HB降解的作用，同时仍使其保持优异的抗老化能力。球磨淀粉接枝工艺为制备具有优异机械性能的廉价全生物可降解P4HB复合薄膜提供了一种简单有效的方法。
