黄麻纤维增强混凝土的抗压和抗折性能研究

在混凝土中添加黄麻纤维,以增强混凝土的抗压和抗折性能。通过测定纤维增强混凝土的抗压和抗折强度,并与素混凝土进行对比,进而研究黄麻纤维的长度和掺量对混凝土的增强作用。结果表明:黄麻纤维长度为30mm,掺量为0.5～0.6kg/m3时,对混凝土的抗压及抗折强度增强作用最为显著。     

High-performance hybrid composites made of recycled Nomex,Kevlar, and polyester selvages: mechanical property evaluations

In modern age, prosperous business, industrial, social, and leisure activities improve and ensure the quality of lives considerably, but are inevitably accompanied with insecurity and dangers that lurk anywhere anytime. People are concerned about safety and have increasing demands on self-protection in terms of working/living environment, accidents, and raising crime rates. The increasing demands of protective textiles cause the mass production of high performance fabrics, leaving considerable amount of high performance selvages. In this study, three kinds of high performance recycled selvages, including Nomex, Kevlar, and PET selvages, are used to make high-performance hybrid composites. The recycled selvages are smashed into staple fibers using a nonwoven manufacturing process. Each recycled staple fibers are individually combined with low-melting-point polyester (LPET) fibers at ratios of 9:1, 7:3, and 5:5, and processed with thermal compression. The LPET fibers contribute to the hybrid composites with thermal bonding points, which decrease the voids between fibers, limit the fiber slide, and enhance the friction force between fibers. The shearing, expelling, and friction functionalities of LPET fibers are expected have a positive influence on the mechanical properties of the high-performance hybrid composites. The morphology of hybrid composites is observed using a scanning electron microscope, and the air permeability, tensile strength, tearing strength, and bursting strength of hybrid composites are evaluated, examining the optimal parameters.     

环氧大豆油木材胶黏剂的制备及其热压工艺的优化

为开发具有较强耐水性的环保可再生胶黏剂,以环氧大豆油（ESO）为原料,选用顺丁烯二酸酐(MA)为固化剂,乙酰丙酮锌〔Zn(acac)2〕为催化剂,制备ESO木材胶黏剂,同时制备了杨木胶合板,考察了MA添加量对胶黏剂性能的影响,通过DSC分析优化了催化剂添加量,对胶黏剂进行了红外光谱和TG/DTG分析,并利用正交实验对热压工艺进行了优化。结果表明：当MA添加量为27%时胶黏剂性能达到最佳;催化剂的最优添加量为3%;通过红外光谱和TG/DTG分析证明ESO与MA发生了交联固化反应;最佳热压工艺为热压温度150 ℃、热压时间10 min、热压压力2 MPa、涂胶量320 g/m2,在此条件下湿态胶合强度为1.613 MPa,符合国家规定的普通胶合板Ⅱ类板要求（≥0.70 MPa）。该胶黏剂制备方法具有简单、高效、环保等优势,是实现ESO在木材产品生产中可持续应用的一种很有前景的策略,具有很大的工业应用潜力。     

水性聚氨酯胶复合非织造布/软木纸材料的性能研究

采用水性聚氨酯（PU）胶对非织造布与软木纸进行复合,通过正交试验探讨了加热温度、加热时间、滚压压力和滚压次数对非织造布／软木纸复合材料剥离强度、弯曲刚度和拉伸强度的影响,采用数理统计分析法得到了水性聚氨酯（PU）胶用于非织造布／软木纸复合材料制作的最佳工艺,并与VEA乳胶的复合结果进行了对比。     

上浆剂对碳纤维复合材料拉伸强度的影响

针对碳纤维复合材料中碳纤维和基体树脂界面结合力弱的问题,对碳纤维进行了上浆处理,分别测试了碳纤维使用水性聚氨酯、聚乙烯醇两种浆料在不同用量、浓度、烘干温度、时间等条件下上浆后,与聚乙烯膜制成的复合材料拉伸断裂强度的变化情况.通过试验得出:水性聚氨酯上浆的最佳浆液质量分数为30％,此时复合材料的断裂强力是无浆丝复合材料断...     

Mechanical properties and microstructure of 3D sinking woven quartz fiber-reinforced silica composites by silicasol-infiltration-sintering

Three-dimensional (3D) sinking woven quartz fiber-reinforced silica composites were successfully prepared by silicasol-infiltration-sintering process at a low temperature of 450°C. The density of the composites was 1.74?g/cm³. The characteristics of 3D sinking woven structure were determined. Flexural strength and shear strength of the composites were investigated along the warp and weft directions. Both flexural stress–displacement curves in warp and weft directions had two fractural points, e.g. matrix fracture point and fiber fracture point. The shear stress–displacement curves exhibited mostly nonlinear behavior. The composite in warp and weft direction reflects different shear behavior. Microstructural observations revealed that the adhesion strength between the fibers and the matrix was weak. There was a good state without serious degradation of quartz fibers during the preparation. Apart from these, the composites exhibited an extensive and long fiber pullout in the fracture surface. Crack deflection and fiber pullout contributed to the good toughness of the composites under the loading.     

等离子体处理聚丙烯无纺布制备复合保鲜材料及其性能研究

目的制备一种聚丙烯(polypropylene,PP)无纺布基复合保鲜材料,研究制备工艺对复合材料力学性能和保鲜效果的影响。方法以聚丙烯无纺布为基材,经等离子体处理后,浸渍壳聚糖溶液,制得壳聚糖/聚丙烯无纺布复合保鲜材料,研究了等离子体处理功率、壳聚糖浓度、温度和时间对复合材料力学性能、微观结构和保鲜性能对其的影响。结果等离子体处理功率80 W、壳聚糖浓度为1.5 wt%、水浴温度60℃、水浴时间45 min时制备的壳聚糖/聚丙烯无纺布复合材料的力学性能最佳,对青椒的保鲜效果最好。结论制备得到的聚丙烯无纺布基复合材料力学性能优异,保鲜性能持久。     

浅谈木塑复合材料及其生产工艺

针对木塑复合材料生产中存在的问题,提供了改善植物纤维与高分子材料相容性的3种有效途径,并通过介绍该复合材料基材和成型设备等选择,简述其生产工艺流程,最后论述了木塑复合材料应用前景。     

Effect on compressive and flexural strength of agave fiber reinforced adobes

Adobe bricks, formed from raw clay, are used as construction materials since ancient times. Their main drawback is a low flexural and compressive strength. Agave bagasse is a waste material from the Mezcal production process. Angustifolia haw agave bagasse fiber was added to improve the properties of adobes. Adobe bricks were made with agave fibers ranging from 10 to 25 mm length and 0.25 to 1% concentration. At 1% concentration of agave, 25 mm long, the compressive and flexural strength are improved by 33% and 7.01%, fulfilling the requirements of Mexican construction regulation norm N-CMT-2-01-001/02 class C.     

Processing of waste carbon and polyamide fibres for high-performance thermoplastic composites: influence of carding parameters on fibre orientation,fibre length and sliver cohesion force

Abstract

The processing of waste carbon fibre on carding machine for the developments of nonwovens, tapes and hybrid yarn structures is an emerging trend. These structures are widely used to enhance the performance efficiency of recycled carbon fibre reinforced thermoplastic composites. The aim of the research presented in this study is to process waste carbon fibre on a carding machine and to investigate the influence of different carding parameters on waste carbon fibre. For this purpose, card slivers composed of waste carbon and polyamide fibres were developed on a double cylinder card machine by varying technical parameters. Then, effect of these parameters on card sliver quality was assessed in terms of fibre orientation, fibre length and sliver cohesion force. Results revealed that fibre orientation and fibre length is significantly affected by technological parameters carding zones, whereas the sliver cohesion force is significantly affected by the speed of feed roller and doffer.