Radiation-Induced Controlled Grafting from Lignocellulosic Fiber Towards Compatibilization for Composite Reinforcement

ABSTRACT

Lignocellulosic natural fibers remain at the forefront of eco-friendly and sustainable reinforcement materials in composites. This work addresses the inherent limitations of lignocellulosic fibers in terms of their hydrophilicity and incompatibility to achieve maximum utilization in most commercial resins using a reversible addition-fragmentation chain transfer radiation-induced graft polymerization (RAFT-RIGP) approach. The one-pot surface modification technique via RAFT-RIGP was shown to efficiently graft poly(glycidyl methacrylate) onto lignocellulosic fibers like abaca. Results from the analyses of the different grafting parameters and polymerization trends reveal that the employed RAFT-mediation improved grafting yield compared to a conventional RIGP despite retardation effects inherent in the RAFT mechanism. Additionally, sufficient control over the molecular weight and dispersity of grafted chains was exhibited. The modified fibers showed improved tensile strength, higher thermal stability and reduced moisture uptake. Overall, we have demonstrated that RAFT-RIGP can be a facile, environment-friendly technique for the surface compatibilization of lignocellulose fibers without the mechanical deterioration of substrate properties, unlike other fiber modification processes. Therefore, this method has a great potential in natural fiber compatibilization for reinforcement in polymer composites.

摘要

木质纤维天然纤维仍然是复合材料中环保和可持续增强材料的最前沿. 这项工作解决了木质纤维在亲水性和不相容性方面的固有局限性，以使用可逆加成-碎裂-链转移辐射诱导接枝聚合（RAFT-RIGP）方法在大多数商业树脂中实现最大利用. 通过RAFT-RIGP的一锅表面改性技术可以有效地将聚甲基丙烯酸缩水甘油酯接枝到abaca等木质纤维纤维上. 对不同接枝参数和聚合趋势的分析结果表明，与传统RIGP相比，所采用的RAFT调解提高了接枝产率，尽管RAFT机制中固有的延迟效应. 此外，还充分控制了接枝链的分子量和分散性. 改性纤维显示出改善的拉伸强度、更高的热稳定性和更低的吸湿性. 总的来说，我们已经证明RAFT-RIGP是一种简单、环保的木质纤维素纤维表面增容技术，与其他纤维改性工艺不同，不会导致基材性能的机械劣化. 因此，该方法在天然纤维增容增强聚合物复合材料方面具有很大的潜力.

KEYWORDS:

• Radiation-Induced graft polymerization
• RAFT
• lignocellulose fiber
• natural fiber composites
• compatibilization

关键词:

• 辐射诱导接枝聚合
• 木质纤维素纤维;
• 天然纤维复合材料
• 增容

Acknowledgment

The authors acknowledge the financial support given by the Department of Science and Technology - Science Education Institute HRDP Program, which sponsored the graduate scholarship of Ms. Barba. This work was also partially supported by JSPS KAKENHI (Grant No. JP17K05956). The authors also acknowledge the Environmental Polymer Group (QST-TARRI) and Dr. Nor Azillah Fatimah for their assistance in carrying out characterization experiments. The authors acknowledge Philippine Council for Industry, Energy, and Emerging Technology Research and Development (DOST-PCIEERD) for the support provided in presenting this work at the 2nd International Conference on Applications of Radiation Science and Technology.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by the Science Education Institute HRDP [n/a]; JSPS KAKENHI [Grant No. JP17K05956].