With the increasing awareness of environmental protection and rational utilization of resources,natural fiber reinforced composites have shown broad development prospects.Apocynum fiber,known as the“king of wild fibe...With the increasing awareness of environmental protection and rational utilization of resources,natural fiber reinforced composites have shown broad development prospects.Apocynum fiber,known as the“king of wild fiber”,not only has moisture absorption,air permeability,and good mechanical properties but also has many health-related advantages such as antibacterial properties.In this study,four types of needle-punched Apocynum fiber and ramie fiber mat reinforced polylactic acid(PLA)composites were fabricated.Mechanical and thermal properties of the composites were tested and analyzed.The results showed that compared with those of the ramie fiber finish needle-punched mat reinforced composites,the tensile strength and the tensile modulus of Apocynum fiber finish needle-punched mat reinforced composites had increased by 15.3%and 60.1%,respectively.In comparison,the bending strength and the bending modulus were decreased by 21.8%and 7.6%,respectively.Moreover,compared with the Apocynum fiber finish needled-punched mat reinforced composites and the ramie fiber finish needle-punched mat reinforced composites,the Apocynum 50/ramie 50 finish needle-punched mat reinforced composites had the best tensile and bending properties.The after-fracture morphology was detected by a scanning electron microscope(SEM).The thermal properties of the composites were also characterized.It was found that the thermal properties of the four types of composites showed very similar behaviors.展开更多
This research investigates the mechanical and thermal properties of Morus alba combined with polylactic acid in comparison with other natural fibers. The study uses three different fiber and PLA compositions - 20%, 30...This research investigates the mechanical and thermal properties of Morus alba combined with polylactic acid in comparison with other natural fibers. The study uses three different fiber and PLA compositions - 20%, 30%, and 40% respectively - to produce composite materials. In addition, another composite with the same fiber volume is treated with a 4% NaOH solution to improve mechanical properties. The composites are processed by twin-screw extrusion, granulation, and injection molding. Tensile strength measurements of raw fibers and NaOH-treated fibers were carried out using a single-fiber tensile test with a gauge length of 40 mm. It was observed that the NaOH surface treatment increases the resistance against tensile loading and exhibited improved properties for raw fiber strands. The diameter of the fibers was measured using optical microscopy. During this research, flexural tests, impact tests, differential scanning calorimetry (DSC), and heat deflection temperature measurements (HDT) were conducted to evaluate the mechanical and thermal properties of the developed composite samples. The results indicate that the mechanical properties of NaOH-treated Morus alba-reinforced polylactic acid outperform both virgin PLA samples and untreated Morus alba samples.展开更多
采用同轴静电纺丝技术制备聚乳酸(PLA)-聚己内酯(PCL)核-壳结构复合纤维.利用扫描电子显微镜(SEM)观察纺丝电压、收集距离和核层-壳层溶液推进速度对PLA-PCL核-壳结构复合纤维形貌的影响.通过透射扫描电子显微镜(TEM)分析核层-壳层溶液...采用同轴静电纺丝技术制备聚乳酸(PLA)-聚己内酯(PCL)核-壳结构复合纤维.利用扫描电子显微镜(SEM)观察纺丝电压、收集距离和核层-壳层溶液推进速度对PLA-PCL核-壳结构复合纤维形貌的影响.通过透射扫描电子显微镜(TEM)分析核层-壳层溶液推进速度对PLA-PCL核-壳结构形成的影响.研究结果表明:当核-壳溶液推进速度为0.1-0.2和0.1-0.3 m L/h时形成了清晰的核-壳结构;随着壳层溶液推进速度加快,PLA-PCL复合纤维核层含量降低,增加纺丝电压能够有效地降低复合纤维平均直径,而增大收集距离使复合纤维平均直径先降低后增加.展开更多
基金National Natural Science Foundation of China(No.50803010)Natural Science Foundation of Shanghai,China(No.14ZR1400100)。
文摘With the increasing awareness of environmental protection and rational utilization of resources,natural fiber reinforced composites have shown broad development prospects.Apocynum fiber,known as the“king of wild fiber”,not only has moisture absorption,air permeability,and good mechanical properties but also has many health-related advantages such as antibacterial properties.In this study,four types of needle-punched Apocynum fiber and ramie fiber mat reinforced polylactic acid(PLA)composites were fabricated.Mechanical and thermal properties of the composites were tested and analyzed.The results showed that compared with those of the ramie fiber finish needle-punched mat reinforced composites,the tensile strength and the tensile modulus of Apocynum fiber finish needle-punched mat reinforced composites had increased by 15.3%and 60.1%,respectively.In comparison,the bending strength and the bending modulus were decreased by 21.8%and 7.6%,respectively.Moreover,compared with the Apocynum fiber finish needled-punched mat reinforced composites and the ramie fiber finish needle-punched mat reinforced composites,the Apocynum 50/ramie 50 finish needle-punched mat reinforced composites had the best tensile and bending properties.The after-fracture morphology was detected by a scanning electron microscope(SEM).The thermal properties of the composites were also characterized.It was found that the thermal properties of the four types of composites showed very similar behaviors.
文摘This research investigates the mechanical and thermal properties of Morus alba combined with polylactic acid in comparison with other natural fibers. The study uses three different fiber and PLA compositions - 20%, 30%, and 40% respectively - to produce composite materials. In addition, another composite with the same fiber volume is treated with a 4% NaOH solution to improve mechanical properties. The composites are processed by twin-screw extrusion, granulation, and injection molding. Tensile strength measurements of raw fibers and NaOH-treated fibers were carried out using a single-fiber tensile test with a gauge length of 40 mm. It was observed that the NaOH surface treatment increases the resistance against tensile loading and exhibited improved properties for raw fiber strands. The diameter of the fibers was measured using optical microscopy. During this research, flexural tests, impact tests, differential scanning calorimetry (DSC), and heat deflection temperature measurements (HDT) were conducted to evaluate the mechanical and thermal properties of the developed composite samples. The results indicate that the mechanical properties of NaOH-treated Morus alba-reinforced polylactic acid outperform both virgin PLA samples and untreated Morus alba samples.
文摘采用同轴静电纺丝技术制备聚乳酸(PLA)-聚己内酯(PCL)核-壳结构复合纤维.利用扫描电子显微镜(SEM)观察纺丝电压、收集距离和核层-壳层溶液推进速度对PLA-PCL核-壳结构复合纤维形貌的影响.通过透射扫描电子显微镜(TEM)分析核层-壳层溶液推进速度对PLA-PCL核-壳结构形成的影响.研究结果表明:当核-壳溶液推进速度为0.1-0.2和0.1-0.3 m L/h时形成了清晰的核-壳结构;随着壳层溶液推进速度加快,PLA-PCL复合纤维核层含量降低,增加纺丝电压能够有效地降低复合纤维平均直径,而增大收集距离使复合纤维平均直径先降低后增加.
