加捻植物纤维增强聚氨酯复合材料的力学特性与疲劳性能

采用多维植筋法制备了软质聚氨酯泡沫/加捻植物纤维（FPUF/TPF）复合材料，研究了植筋方向、TPF毛羽率及植筋体积分数对FPUF/TPF结合界面、力学性能、耐疲劳性能的影响。结果表明，植筋后复合材料的力学性能及耐疲劳性能均有所提升，植筋体积分数在0.35 %~0.7 %之间时，复合材料能在保证轻质的前提下得到较好的性能增强。植筋后力学性能的增强表现为压陷硬度提升，最高可提升89.69 %；压陷比普遍提高，最高达3.56，提升了37.98 %，支撑性能得到提升；横向植筋样品的滞后损失率普遍降低，作为垫材时样品舒适感提升；纵向植筋样品的滞后损失率普遍升高，缓冲性能有所提升。植筋后复合材料耐疲劳性能的增强表现为抗蠕变抗变形能力提升，长时间使用后变形更小；40 %压陷硬度损失率最低为11.01 %，降低了38.59 %，植筋后的循环次数最高可达空白样品（FPUF）的4.1倍；压缩永久变形率较空白样品降低29.63 %。同时对比发现，横向植筋样品的结合界面优于纵向植筋，毛羽较少的TPF与聚氨酯的界面性能较好，过多的毛羽会一定程度上影响泡孔大小和形态。

Mechanical and fatigue properties of twisted?plant?fiber?reinforced polyurethane composites

Flexible polyurethane foam （FPUF）/twisted plant fiber （TPF） composites were prepared using a multidimensional implanting method. The effects of the implantation direction， hairiness rate， and volume fraction of TPF on the interface bon?ding， mechanical properties， and fatigue resistance of FPUF/TPF were investigated. The results indicated that the mechanical properties and fatigue resistance of the composites were improved after the TPF was planted. When the volume fraction of TPF implantation was set between 0.35 % and 0.7 %， the composites obtained a better enhancement in performance together with a lightweight. The enhancement of mechanical properties after planting bars reflected an increase in indentation hardness， which increased by up to 89.69 %. The indentation ratio was generally improved up to 3.56， resulting in an increase by 37.98 %. The composites also showed an improvement in support performance. The transversely planted reinforcement samples generally presented a decrease in hysteresis loss rate， improving their comfortability when used as a cushion material.The longitudinally plan?ted reinforcement samples generally presented an increase in hysteresis loss rate， leading to an improvement in buffering performance. The enhancement of fatigue resistance of the composites after planting bars reflected an improvement in creep resistance and deformation resistance， and the deformation was smaller after long?term use. After bar implantation， the 40% indentation hardness loss rate was reduced to a minimum of 11.01 %， showing a decrease by 38.59 %. The cycle times after bar implantation reached 4.1 times than that of the blank sample. A comparative study indicated that the transversely plan?ted samples had a better interface than the longitudinally planted ones. The TPF with less hairiness had a better interface with polyurethane， and too much hairiness might affect the size and shape of the cells to a certain extent.