The TPB Properties of Plasma-Treated Carbon Fiber-Reinforced Polystyrene Composites

Dielectric barrier discharges (DBD) in ambient air are used on carbon fiber to improve the fiber surface activity. Carbon fibers with length of 75 µm are placed into the plasma configuration. The interaction between modified carbon fibers and polystyrene was studied by the three-point bending (TPB) test. The chemical and physical changes induced by the treatments on carbon fiber surface are examined using contact angle measurements and X-ray photoelectron spectroscopy (XPS). Contact angles of the plasma-treated carbon fiber and XPS results reveal that the carbon fibers modified with the DBD at an atmospheric pressure show a significant increase in oxygen and nitrogen concentration. These results demonstrate that the surfaces of the carbon fiber are more active, hydrophilic after plasma treatments using a DBD operating in ambient air.     

介质阻隔空气等离子处理聚丙烯无纺布的研究

使用介质阻隔空气等离子技术(DBD)对聚丙烯(PP)无纺布进行处理,以改善PP无纺布的润湿性。扫描电镜分析表明:经DBD处理后,PP无纺布表面有明显的刻蚀和凸状沉积物,润湿性得到改善,随DBD处理功率的增大,PP无纺布润湿性相应增强。     

几种纤维在增强混凝土中的应用

介绍了聚丙烯纤维、碳纤维、钢纤维和玻璃纤雏增强混凝土的基本性能,其中聚丙烯纤维有较好的技术经济性能,已在混凝土工程中广泛应用;由于碳纤维等后3种纤维有高强、高模和韧性,可用于次结构甚至主结构的增强或加固用。同时简介了国内外研究情况以及一些实际应用案例,指出今后有待研究的问题和研究的重点及方向。     

聚丙烯/膨胀石墨/碳纤维导热复合材料

研究了聚丙烯(PP)/膨胀石墨(EG)/碳纤维(CF)复合材料的导热、力学以及加工性能.研究发现:当膨胀石墨的质量含量达到20％时,热导率是纯聚丙烯的2倍,但熔体流动性能有所下降;添加1％的聚乙烯蜡可以明显改善体系的熔体流动性能;将膨胀石墨与5％的碳纤维杂化使用,热导率达0.91 W·m-1K-1,是纯聚丙烯的5倍,熔体指数达到1.72 g/10 min,同时该复合材料具有较好的力学性能.     

Yttria–polystyrene–polypropylene composite for fine dyeable fibers

Fine polypropylene fiber has many excellent properties, but it is difficult to dye because of the absence of dye sites in the molecular chain and high crystallinity. Fine polypropylene/hybrid polystyrene (yttria) fiber melt‐spun from blends of polypropylene and a small amount of nanohybrid polystyrene with modified yttria incorporated was prepared to improve the dyeing properties. The dyeability, orientation, degree of crystallinity, phase morphology, and mechanical properties of pure polypropylene and the blend fibers were investigated. It was found that the crystallinity and morphology of these phases in the blend systems were different. With the existence of nanohybrid polystyrene, the fine modified polypropylene filaments had practical mechanical properties, the amorphous region of the polypropylene/hybrid polystyrene (yttria) fiber increased, and the modified polypropylene fiber dyed easily and had good fastness to soaping because of the complexation of the disperse dye and yttrium in the blend system. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

高掺量聚丙烯纤维自密实混凝土制备及其性能研究

为了有效提高高掺量聚丙烯纤维自密实混凝土的工作性能,将调整水胶比和砂率进行配制聚丙烯纤维体积掺量为0.5％的自密实混凝土并对其材料性能进行试验研究.研究表明:高掺量聚丙烯纤维的掺入对自密实混凝土的流动性有较大影响,适当调整水胶比和砂率可配制满足工作性能要求的高掺量聚丙烯纤维自密实混凝土;水胶比的增大提高了高掺量聚丙烯纤维自密实混凝土的扩展度,同时也提高了其离析的风险,降低了其抗压强度;砂率的增大对高掺量聚丙烯纤维自密实混凝土的抗压强度基本没有影响,但可提高其拌合物的粘聚性.     

丙纶纤维自增强聚丙烯树脂的研究

以丙纶纤维为增强体,聚丙烯树脂为基体,采用热压成型的方法制备丙纶纤维/PP复合材料板材.研究了不同热压温度、不同纤度的丙纶纤维用量对复合材料力学性能的影响.结果表明:本实验最佳热压温度为195℃,在此温度下,随着纤维用量的增加,复合材料的拉伸强度呈先升后降的趋势,在用量为15%时达到最高点,纤度为240D的丙纶纤维/P...     

纳米SiO2和聚丙烯纤维对煤矸石二灰混合料改性试验研究

为了研究纳米SiO₂和聚丙烯纤维对煤矸石二灰混合料力学性能及水稳定性能的影响,通过无侧限抗压强度试验、劈裂试验测得各组试件改性前后强度值,并对干湿循环后试件质量、强度值及声发射特性进行分析。结果表明:纳米SiO₂可以提高煤矸石二灰混合料的抗压强度,掺量为2.5%(质量分数)时效果最佳;同时加入纳米SiO₂和聚丙烯纤维可以进一步提升混合料的力学性能,掺加2.5%纳米SiO₂和0.15%(体积分数)聚丙烯纤维时煤矸石二灰混合料力学性能最好;掺加2.5%纳米SiO₂和0.10%(体积分数)聚丙烯纤维的煤矸石二灰混合料水稳定性能最佳。     

Recycled polypropylene reinforced with curaua fibers by extrusion

Curaua fibers were studied as reinforcing agents for postconsumer polypropylene. The composites were processed by extrusion. The composite properties were investigated by mechanical tests, thermal methods, melt flow index, surface morphology, and water uptake. The variables studied were as follows: fiber contents (10 to 40 wt %), fiber surface treatment, initial fiber length, and modification of the polypropylene matrix. The treatment of the fiber with 5 wt % NaOH aqueous solution did not improve fiber‐matrix adhesion and the composites using 20 wt % of untreated curaua fibers presented the better mechanical properties. Feeding the extruder with fibers having shorter lengths (0.01–0.4 mm) produced better fiber dispersion, improving the mechanical properties of the composites. Composites prepared using fibers without surface treatment with postconsumer polypropylene and with polypropylene modified with maleic anhydride showed mechanical properties and water uptake similar to composites using the same polymer reinforced with other lignocellulosic fibers. The extrusion process caused also partial fibrillation of the fibers, improving their aspect ratio. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Studies on the modification of interphase/interfaces by use of plasma in certain polymer composite systems

Calcium carbonate and carbon fiber surfaces were modified by use of a series of plasma polymers at different selected plasma conditions, and the effect of surface modification, mainly on the mechanical properties of composite systems prepared, was investigated. The matrices for the composite systems employed were polypropylene and epoxy, for the chalk and C fiber, respectively. Mechanical and thermal studies and scanning electron microscopy (SEM) pictures revealed that inclusion surfaces, being independent of their geometry and size, can be modified effectively by plasma. A polypropylene matrix with 30% modified chalk had better properties than composites with 10% unmodified chalk. Tensile strength and stress to failure values for single carbon fibers were found to be improved by plasma treatment. Surface-treated carbon fibers yielded at composites with better interlaminar shear strength and flexural strengths.     

玻璃纤维增强聚丙烯复合材料耐水解性能的研究

以玻璃纤维增强聚丙烯复合材料为研究对象,选取两种玻璃纤维、不同相容剂及不同含量探讨玻璃纤维增强聚丙烯复合材料的性能,研究了在95℃水煮24 h前后的力学性能、微观结构和结晶变化。结果表明,添加聚丙烯专用耐水解玻璃纤维,在相容剂含量为3%时,可以大大提高聚丙烯材料的力学性能和耐水解性能,已经被应用于洗衣机滚筒等长期水接触的部件。     

介质阻挡放电等离子体改性碳基材料研究进展

介质阻挡放电等离子体因其高效、经济和易操作等优点, 使得其在材料表面改性方面得到了广泛的应用, 同时表现出良好的应用前景。碳基材料由于其许多良好的物化性能, 使得其在很多领域都得到了很好的应用。而经DBD改性后的碳基材料表现出更好的物化性能, 应用更加广泛。主要综述了DBD在改性碳基材料方面的研究现状, 包括活性基团的引入, DBD改性对碳基材料界面结合能、吸附性能、物理结构及其对负载组分分散度的影响。指出改性过程中仍然存在的许多不够完善之处, 提出许多需要进一步深入研究的问题, 如DBD改性对碳基材料物化性能影响的机理研究, 并展望了DBD改性碳基材料技术未来的发展前景。     

聚烯烃类弹性体导电复合材料的制备与性能研究

将炭黑(CB)和碳纤维(CF)导电粒子加入到新型聚丙烯弹性体(Vistamaxx)与聚丙烯(PP)基体树脂中,共混制备导电复合材料。通过体积电阻率测试、力学性能测试和加工流变性能测试,得到了体积电阻率最低为0.47Ω.cm,拉伸强度为6.6 MPa,断裂伸长率为250%,具有良好加工性能的导电复合材料。     

Progress in Carbon Fiber and Its Polypropylene- and Polyethylene-Based Composites

Due to their lightweight and excellent toughness, carbon fiber (CF) and its reinforced thermoplastic composites are suitable for high-performance applications such as aerospace, aviation, automotive and sport equipments. In this study, comprehensive detail is provided on the production of carbon fiber, its various forms and geometry and their corresponding effects on the mechanical properties of CF and its reinforced polypropylene (PP) and polyethylene (PE) composites. Here we discuss extensively various methods reported in literature on improving the interfacial fiber-matrix adhesion and dispersion in order to achieve better mechanical properties for such composites.     

长纤维增强聚合物注塑成型过程中三维网络结构的调控

以长玻纤增强聚丙烯(PP)注塑制品为研究对象,通过引入微、纳尺度第二增强相调控长纤维在注塑制品中的取向度,从而获得取向度较低的皮层结构,以诱导长纤维在注塑件空间内形成连续、均匀的三维网络结构,从而明显提高制品的力学性能.对不同尺度混杂填充长纤维注塑微观结构的比较分析结果表明:加入纳米尺度第二相碳纳米管(CNTs),在基...     

未改性聚丙烯纤维的超临界染色研究进展

综述了未改性聚丙烯纤维的超临界染色研究进展。在超临界二氧化碳中,染料可以扩散至纤维内部,与传统的方法相比,染色结果有很大的提高。超临界二氧化碳作为未改性聚丙烯纤维染色媒介是可行的。有25篇参考文献。     

Improving the interface bond between fiber mesh and cementitious matrix

The use of continuous fiber mesh as reinforcement of cementitious composites is attractive for various applications. In this paper, fracture toughness was used to evaluate the flexural behavior of glass concrete reinforced with either AR-glass or polypropylene fiber mesh. AR-glass fiber mesh was found to be much more efficient, but polypropylene fiber mesh is less expensive and has no aging problem. A research project is underway at Columbia University to improve the bond between the polypropylene fiber mesh and cementitious matrix. Results obtained so far indicate a great improvement of the mechanical properties of the fiber mesh-reinforced material.     

Polyolefin-nanocomposites with special properties by in-situ polymerization

Exceptionally strong polyolefin nanocomposites are synthesized by in-situ polymerization using soluble metallocene/methylaluminoxane (MAO) as catalysts in a two-step process. First, the soluble metallocene/MAO or other single site catalysts are absorbed on the surface of the nanofillers. Then by addition of ethene or propene, a polyolefin film is formed, covering the nanoparticles, layered silicates, or fibers. The resulting polyethylene and polypropylene nanocomposites are characterized by better physical and chemical properties such as stiffness, gas barrier properties, degradation temperatures, and crystallization rates. They show better mechanical properties than materials produced by mechanical blending. The thickness of the polyolefin can be controlled by the pressure of ethene or propene and by the polymerization time. Carbon fibers and carbon nanotubes are covered with isotactic or syndiotactic polypropylene. Because of the hydrophobic character of the carbon surface, the polymer is drawn on the fiber. This leads to a reinforced combined polymer with special properties. The crystallization temperature is 10 °C higher and therefore the crystallization rate up to 20 times faster than that of pure syndiotactic polypropylene. The form stability increases by 100% if 3 wt-% of carbon nanotubes are incorporated.     

介质阻挡放电技术处理挥发性有机物的研究进展

介质阻挡放电技术在处理低浓度挥发性有机物（VOCs）过程中具有反应快速、工艺简单及适应范围广等优点而受到广泛关注。本文从介质阻挡放电单独使用和介质阻挡放电协同催化两方面进行了概括总结。首先,简述了介质阻挡放电处理VOCs所用的驱动电源和等离子体发生器的研究现状及气体性质对VOCs降解性能的影响;其次,介绍了介质阻挡放电协同催化的两种方式（内置式和后置式）及各自情况下采用不同催化剂强化VOCs去除性能、提高能量效率、抑制副产物生成的过程机理;最后,分析了介质阻挡放电技术处理低浓度VOCs过程中存在的关键问题,并提出了未来的重要研究方向为：等离子体催化体系中VOCs的界面反应机理;催化剂的抗积碳性能的提高;适用于多组分VOCs的高效催化剂的开发。     

长玻纤增强聚丙烯复合材料的制备及力学性能

使用熔融浸渍法制备了长玻璃纤维增强聚丙烯复合材料(LFTPP–G),研究了不同纤维含量、不同牵引速度及不同相容剂马来酸酐接枝聚丙烯(PP-g-MAH)添加量对复合材料力学性能的影响。结果表明,玻璃纤维在复合材料体系中起增强增韧作用,复合材料力学性能随纤维含量增加而升高;提高牵引速度可以提高生产效率,但复合材料的力学性能及纤维分散性能随之降低;相容剂PP-g-MAH的加入改善了玻璃纤维与树脂的界面结合。当使用自制的浸渍装置且玻璃纤维质量分数为50%、牵引速度为30 m/min、相容剂PP-g-MAH质量分数2%时,制得LFTPP–G具有较好的综合力学性能,其缺口冲击强度相较于纯聚丙烯树脂提高了1323%。