生物基成核剂对聚 L-(乳酸)的结晶、流变和力学性能的影响。
Biobased nucleation agents for poly-L-(lactic acid) - Effect on crystallization, rheological and mechanical properties.
机构信息
University of Sfax, LMSE, Faculty of Science, BP 802, 3018 Sfax, Tunisia.
Univ. Grenoble Alpes, CNRS, Grenoble INP, LRP, F-38000 Grenoble, France.
出版信息
Int J Biol Macromol. 2022 Oct 1;218:588-600. doi: 10.1016/j.ijbiomac.2022.07.069. Epub 2022 Jul 14.
In the present work, the nucleating aptitude for poly-L-(lactic acid) (PLLA) of several biobased nanoparticles (NPs) with different morphologies and surface properties, including cellulose nanofibrils with and without lignin (LCNFs and CNFs) as well as cellulose, chitin and starch nanocrystals (CNCs, ChNCs and SNCs), was investigated. A single melt-processing step using a small amount of poly(ethylene glycol) (PEG) as carrier for the NPs was adopted to prepare films with the same nanofiller content of 1 wt%. The nucleation efficiency was investigated by differential scanning calorimetry using Avrami's and Lauritzen-Hoffman's secondary nucleation theory. The crystallization half-time was found to change considerably according to the morphology and surface properties of the NPs, with the lowest time observed for CNFs and CNCs, followed by ChNCs, SNCs and LCNFs. Comparing the surface energy components of the different nucleating agents, it was found that the nanofiller with the highest γ had the lowest t and demonstrated the most effective nucleating aptitude. The evolution of the melt rheological properties of the different compositions, and the mechanical and optical properties of the films with and without a short annealing treatment were also studied.
在本工作中,研究了几种具有不同形貌和表面性质的生物基纳米粒子(NPs)对聚 L-(乳酸)(PLLA)的成核能力,这些 NPs 包括带有和不带有木质素的纤维素纳米纤维(LCNFs 和 CNFs)以及纤维素、壳聚糖和淀粉纳米晶(CNCs、ChNCs 和 SNCs)。采用少量聚乙二醇(PEG)作为 NPs 的载体,通过单次熔融加工步骤来制备具有相同纳米填料含量(1wt%)的薄膜。通过使用 Avrami 和 Lauritzen-Hoffman 的次级成核理论的差示扫描量热法研究了成核效率。发现结晶半时间根据 NPs 的形貌和表面性质有很大的变化,其中 CNFs 和 CNCs 的时间最短,其次是 ChNCs、SNCs 和 LCNFs。比较不同成核剂的表面能分量,发现具有最高γ值的纳米填料具有最低的 t 值,表现出最强的成核能力。还研究了不同组成的熔体流变性能的演变,以及经过短退火处理和未经退火处理的薄膜的力学和光学性能。