Evaluation and Impact Factors of the Mechanical Properties of Phloem Bundle Fibers Obtained from Kenaf Germplasm

The mechanical properties of kenaf phloem bundle fibers are valuable for reinforced composites or boards, more so than similar materials also used in textile or papermaking applications. 55 kenaf germplasm studied here showed an average phloem bundle fiber tensile strength of 643.6 MPa and an average elastic modulus of 23.3 GPa after chemical retting treatment. 19 of these kenaf germplasm had fiber tensile strengths >700 MPa, which can be attributed to intensive breeding programs. The fiber tensile strength and elastic modulus of kenaf germplasm had a significant positive correlation, but there was no such correlation between a fiber’s mechanical properties and its diameter or agronomic characteristics. Among 56 hybridized combination F1 generations, the highest tensile strength was 928.3 MPa from a combination of No.30 of Xinan Wuchi × Guatemala 4. Therefore, breeding and screening are both useful for improving the mechanical properties of kenaf phloem bundle fibers. However, the effects of the used bundle fiber preparation method or cultivation year on the fiber’s mechanical properties were more pronounced than those of the type of kenaf germplasm or breeding operation used. The mechanical properties of kenaf phloem bundle fibers treated by chemical retting were superior to those treated using natural retting.

红麻韧皮束纤维的力学性能在增强复合材料或板材领域具有重要应用价值，其应用潜力优于同样用于纺织或造纸领域的同类天然纤维材料。本研究涉及的55份红麻种质资源，经化学脱胶处理后，其韧皮束纤维的平均拉伸强度为643.6 MPa，平均弹性模量为23.3 GPa。其中19份红麻种质的纤维拉伸强度超过700 MPa，这一优异表现可归因于高强度的育种选育工作。红麻种质的纤维拉伸强度与弹性模量呈显著正相关，但纤维力学性能与纤维直径或农艺性状之间并无此类相关性。在56个杂交组合F1代中，以西南无刺30号（Xinan Wuchi No.30）与危地马拉4号（Guatemala 4）杂交得到的组合，其纤维拉伸强度最高，达928.3 MPa。由此可见，育种与筛选工作均可有效提升红麻韧皮束纤维的力学性能。但相较于红麻种质类型与育种手段，纤维制备工艺与种植年份对纤维力学性能的影响更为显著。经化学脱胶处理的红麻韧皮束纤维，其力学性能优于天然脱胶处理的样品。