CICECO-Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
RAIZ-Research Institute of Forest and Paper, The Navigator Company, Rua José Estevão, 3800-783 Eixo, Portugal.
Molecules. 2021 Sep 15;26(18):5594. doi: 10.3390/molecules26185594.
Green composites, composed of bio-based matrices and natural fibers, are a sustainable alternative for composites based on conventional thermoplastics and glass fibers. In this work, micronized bleached Eucalyptus kraft pulp (BEKP) fibers were used as reinforcement in biopolymeric matrices, namely poly(lactic acid) (PLA) and poly(hydroxybutyrate) (PHB). The influence of the load and aspect ratio of the mechanically treated microfibers on the morphology, water uptake, melt flowability, and mechanical and thermal properties of the green composites were investigated. Increasing fiber loads raised the tensile and flexural moduli as well as the tensile strength of the composites, while decreasing their elongation at the break and melt flow rate. The reduced aspect ratio of the micronized fibers (in the range from 11.0 to 28.9) improved their embedment in the matrices, particularly for PHB, leading to superior mechanical performance and lower water uptake when compared with the composites with non-micronized pulp fibers. The overall results show that micronization is a simple and sustainable alternative for conventional chemical treatments in the manufacturing of entirely bio-based composites.
绿色复合材料由生物基基质和天然纤维组成，是基于传统热塑性塑料和玻璃纤维的复合材料的可持续替代品。在这项工作中，微米化漂白桉木牛皮纸浆 (BEKP) 纤维被用作生物聚合物基质（即聚乳酸 (PLA) 和聚羟基丁酸酯 (PHB)）的增强材料。研究了机械处理微纤维的负载和纵横比对绿色复合材料的形态、吸水率、熔体流动性以及机械和热性能的影响。纤维负载的增加提高了复合材料的拉伸和弯曲模量以及拉伸强度，而降低了其断裂伸长率和熔体流动速率。微米化纤维的纵横比降低（范围为 11.0 至 28.9）改善了它们在基质中的嵌入性，特别是对于 PHB，与具有非微米化纸浆纤维的复合材料相比，其机械性能更优，吸水率更低。总体结果表明，微米化是制造完全基于生物的复合材料的传统化学处理的简单且可持续的替代方法。
