Avella Angelica, Rafi Abdolrahim, Deiana Luca, Mincheva Rosica, Córdova Armando, Lo Re Giada
Department of Industrial and Materials Science, Chalmers University of Technology, Rännvägen 2A, Göteborg 41258, Sweden.
Department of Natural Sciences, Mid Sweden University, Holmgatan 10, Sundsvall 85170, Sweden.
ACS Sustain Chem Eng. 2024 Jul 12;12(29):10727-10738. doi: 10.1021/acssuschemeng.4c01309. eCollection 2024 Jul 22.
Ethylene brassylate is a renewable macrolactone from castor oil that can be polymerized via ring-opening polymerization (ROP) to obtain a fully biosourced biodegradable polyester. ROP mediated by organometallic catalysts leads to high molar mass poly(ethylene brassylate) (PEB). However, the use of metal-free organocatalysis has several advantages, such as the reduction of toxic and expensive metals. In this work, a novel cellulose nanofibril (CNF)/PEB nanocomposite fabrication process by organocatalysis and reactive extrusion (REx) is disclosed. Here, ROP was carried out via solvent-free REx in the presence of CNFs using organic 1,5,7-triazabicyclo[4.4.0]dec-5-ene as a catalyst. Neat or lactate-esterified CNFs (LACNF) were used as initiators to investigate the effect of surface topochemistry on the in situ polymerization and the properties of the nanocomposites. A molar mass of 9 kDa was achieved in the presence of both unmodified and LACNFs with high monomer conversion (>98%) after 30 min reaction in a microcompounder at 130 °C. Tensile analysis showed that both nanofibril types reinforce the matrix and increase its elasticity due to the efficient dispersion obtained through the grafting from polymerization achieved during the REx. Mechanical recycling of the neat polymer and the nanocomposites was proven as a circular solution for the materials' end-of-life and showed that lactate moieties induced some degradation.
乙撑巴西酯是一种源自蓖麻油的可再生大环内酯，可通过开环聚合（ROP）进行聚合，以获得完全生物源的可生物降解聚酯。由有机金属催化剂介导的ROP可得到高摩尔质量的聚乙撑巴西酯（PEB）。然而，使用无金属有机催化有几个优点，比如减少有毒且昂贵的金属。在这项工作中，公开了一种通过有机催化和反应挤出（REx）制备新型纤维素纳米原纤维（CNF）/PEB纳米复合材料的工艺。在此，在CNF存在的情况下，使用有机1,5,7-三氮杂双环[4.4.0]癸-5-烯作为催化剂，通过无溶剂REx进行ROP。使用纯的或乳酸酯化的CNF（LACNF）作为引发剂，以研究表面拓扑化学对原位聚合和纳米复合材料性能的影响。在微型混合器中于130℃反应30分钟后，在未改性的和LACNF存在的情况下，单体转化率高（>98%），实现了9 kDa的摩尔质量。拉伸分析表明，由于通过REx过程中实现的接枝聚合获得了有效分散，两种纳米原纤维类型都增强了基体并提高了其弹性。纯聚合物和纳米复合材料的机械回收被证明是材料寿命结束后的一种循环解决方案，并且表明乳酸部分会导致一些降解。
