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1.
The evolvement of microstructure and properties of nascent fibers during coagulation process in the polyacrylonitrile (PAN) wet-spinning and the effect of coagulation bath conditions on the structure and properties of the nascent fibers were investigated by the means of X-ray diffraction (XRD), scanning electron microscope (SEM), fiber fineness machine, fiber tensile strength machine, etc. The experimental results indicate that the nascent fibers become denser and have fewer inner defects, the diameter of n...  相似文献   

2.
The effect of coagulation temperature on the morphology, microstructures and mechanical properties of dihydroxy poly(p-phenylene benzobisoxazole) (DHPBO) fibers was investigated during dry-jet wet-spinning process, in which the coagulation bath concentration and drawn ratio were kept as 10 wt% of PPA in water and 1.7, respectively. The structures and mechanical properties of the as-spun DHPBO fibers were characterized by FTIR, XRD, SEM, and single fiber tensile testing. The results indicated that in PPA/H2O coagulation system, when the coagulation temperature was 25°C, highly crystallized DHPBO as-spun fibers possessing fine crystallites, circular and smooth morphology, and excellent mechanical properties could be achieved. Supported by the National Natural Science Foundation of China (Grant No. 50673017), Shanghai Leading Academic Discipline Project (Grant No. B603) and the Program of Introducing Taleuts of Discipline to University of People’s Republic of China (“111” Program) (Grant No. 111-2-04)  相似文献   

3.
The effect of coagulation temperature on the morphology, microstructures and mechanical properties of dihydroxy poly(p-phenylene benzobisoxazole) (DHPBO) fibers was investigated during dry-jet wet- spinning process, in which the coagulation bath concentration and drawn ratio were kept as 10 wt% of PPA in water and 1.7, respectively. The structures and mechanical properties of the as-spun DHPBO fibers were characterized by FTIR, XRD, SEM, and single fiber tensile testing. The results indicated that in PPA/H2...  相似文献   

4.
To understand the enhancing effect and fiber-reinforced mechanism of composite fibers reinforced cement concrete, the influences of composite fibers on micro-cracks and the distribution of composite fibers were evaluated by optical electron micrometer(OEM) and scanning electron microscope(SEM). Three kinds of fiber, such as polyacrylonitrile-based carbon fiber, basalt fiber, and glass fiber, were used in the composite fibers reinforced cement concrete. The composite fibers could form a stable structure in concrete after the liquid-phase coupling treatment, gas-liquid double-effect treatment, and inert atmosphere drying. The mechanical properties of composite fibers reinforced concrete(CFRC) were studied by universal test machine(UTM). Moreover, the effect of composite fibers on concrete was analyzed based on the toughness index and residual strength index. The results demonstrated that the composite fibers could improve the mechanical properties of concrete, while the excessive amount of composite fibers had an adverse effect on the mechanical properties of concrete. The composite fibers could significantly improve the toughness index of CFRC, and the increment rate is more than 30%. The composite fibers could form a mesh structure, which could promote the stability of concrete and guarantee the excellent mechanical properties.  相似文献   

5.
采用湿法纺丝法制备了水解聚丙烯腈/羟基磷灰石复合纤维,考察了凝固浴成分比例、凝固浴温度、凝固浴中碱浓度、冷牵伸比、热牵伸比及二浴水解时间等工艺因素对聚丙烯腈/羟基磷灰石复合纤维强力的影响。研究结果表明,水解聚丙烯腈/羟基磷灰石复合纤维具有可纺性,具有良好的强力。在NaOH水溶液/二甲基亚砜质量比为2∶8、NaOH水溶液浓度1mol/L、凝固温度10℃、喷丝头牵伸比1∶2、冷牵伸比1∶2、热牵伸比8倍和无二浴水解的条件下,所制备的水解聚丙烯腈/羟基磷灰石复合纤维具有很好的强力。  相似文献   

6.
废弃液体包装盒纤维回收及性能分析   总被引:1,自引:0,他引:1  
研究了在不同的解离条件下,废弃液体包装盒纤维回收工艺对回收的纤维采用Morficompact纤维分析仪进行纤维性能分析,并用FBRM颗粒度分析仪观察铝粉颗粒在纤维上的附着情况.研究结果表明:原料尺寸2×2cm,转数2000r/min,温度50℃,固液比10g:2000mL时,为纤维回收最佳的解离工艺条件,回收的纤维形态质量良好,解离过程中铝塑会发生损失,纤维会有铝塑颗粒的附着,铝塑颗粒的附着越少,纤维分散越好.  相似文献   

7.
利用竹纤维制备了水泥基复合材料,采用正交试验法得到了纤维掺量、纤维长度、减水剂和水灰比四个因素的最佳试验条件.在此基础上测试了该复合材料在不同龄期抗压强度和抗折强度.针对竹纤维的机械性能在碱性水泥浆中会逐渐恶化的缺点,对竹纤维表面预涂了乳液并进行了耐久性对比测试.结果表明,加入预处理的竹纤维制备出的水泥基复合材料的力学性能和耐久性得到了显著改善.  相似文献   

8.
以聚醚砜为膜材料,N-甲基吡咯烷酮(NMP)为溶剂,乙醇(Ethanol)为非溶剂,NMP-Water为芯液,PES:NMP:Ethanol 35:57:8为铸膜液,采用干/湿相转化法制备了超薄致密选择性分离层PES中空纤维膜,讨论了芯液组成、芯液流量、硅橡胶种类、芯和凝胶槽温度对PES-A中空纤维膜结构、气体性能和机械性能的影响.实验结果表明,适宜的纺丝条件如下:凝胶槽温度17℃,芯液组成NMP:Water86:14,芯液流量0.15mL/min.在适宜的纺丝条件下,比较了PES-A和PES-B2种聚醚砜膜材料的O2/N2气体分离性能,PES-B中空纤维膜的O2/N2选择性为6.23,其O2渗透通量为9.65GPU.此外,在凝胶槽温度9~24℃范围内,PES-B中空纤维膜的O2/N2选择性为5.28~6.23,O2渗透通量为9.65-10.3GPU,并且其超薄致密选择性分离层为427-456A.因此,PES-B中空纤维膜更适合应用于气体分离.  相似文献   

9.
Cross-linked polystyrene/glass fiber composites were fabricated using cross-linked polystyrene (CLPS) as matrix and E-glass fiber as the reinforcement. Surfaces of E-glass fibers were modified by vinyl triethoxysilane (VTES), vinyl trimethoxysilane (VTMS) and γ-methacryloylpropyl trimethoxysilane (MPS). The treated glass fibers were analyzed by fourier transform infrared spectroscopy (FTIR). Dynamic mechanical thermal analysis (DMTA) and thermo-gravimetric analysis (TGA) were employed to investigate the effect of glass fibers surface modification on viscoelastic behavior and thermal properties. The morphology of fracture surfaces of various composites was observed by scanning electron microscopy (SEM). The results revealed that these coupling agents were connected to the surfaces of the fibers by chemical bonding. Dynamic mechanical properties as well as thermal stability of the composites were improved considerablely, but to varying degrees depending on the fiber modification. The diversities of improvement of properties were attributed to the different interfacial adhesion between CLPS matrix and the glass fibers.  相似文献   

10.
凝固浴对蓄热调温聚丙烯腈纤维性能的影响   总被引:1,自引:1,他引:0  
以聚酰胺石蜡相变微胶囊(MEPCM)为相变材料,硫氰酸钠(NaSCN)水溶液为溶剂,通过湿法纺丝工艺制备MEPCM质量分数为16.7%的蓄热调温聚丙烯腈纤维,考察了凝固浴中NaSCN质量分数对纤维性能的影响。随着NaSCN质量分数的增大,纤维的线密度增大,断裂强度、热收缩率和沸水收缩率下降,断裂伸长率和钩接强度先增大后减小。通过实验分析确定最佳NaSCN质量分数为10%,在此条件下制备的蓄热调温聚丙烯腈纤维强度为1.35cN/dtex,热焓值为26.0J/g,MEPCM在纤维中的热效率达到78.4%,具有良好的物理机械性能和较好的蓄热调温性能。  相似文献   

11.
在凝固浴中加入经酸处理的多壁碳纳米管(MWNTs),制得多壁碳纳米管-聚丙烯腈纤维,并对其进行了表征.结果表明:在凝固浴中加入酸处理MWNTs,对填补PAN碳纤维原丝内部的微孔有明显的作用;对PAN原丝的结晶结构几乎没有影响;降低了原丝的晶区取向;提高了原丝的断裂强度、断裂伸长率及拉伸韧度.  相似文献   

12.
为提高聚丙烯腈(PAN)纤维的阻燃性能,采用紫外光接枝技术,以二苯甲酮(BP)为光引发剂将丙烯酰胺(AM)单体接枝到PAN纤维上,详细研究了AM及BP质量分数、接枝时间及接枝距离对PAN纤维光接枝AM的接枝率(GP)的影响规律,并利用傅里叶红外光谱(FTIR)、X-射线衍射光谱(XRD)、扫描电子显微镜(SEM)对接枝前后的PAN纤维进行了表征,同时,采用热重(TG)及差示扫描量热(DSC)对纤维的热性能进行了研究。结果表明:随着AM及BP质量分数的增大、接枝时间的延长及接枝距离的增大,GP均呈现先增大后减小的趋势,接枝AM后PAN纤维的热性能有所提高,800℃时的残炭量增加,极限氧指数值增大了33.3%。  相似文献   

13.
Epoxy polymer concrete (EPC) has found various applications in civil engineering. To enhance the flexural performance of EPC, two kinds of short natural fibers with high specific strength (sisal fibers and ramie fibers) have been incorporated into EPC. The results of mechanical tests show that a small loading of natural fibers (0.36 vol%) can significantly increase the flexural strength of EPC by 25.3% (ramie fibers) or 10.4% (sisal fibers). This enhancement is achieved without any sacrifice of compressive strength of EPC. The reinforcing effects of short natural fibers on the flexural properties and compressive properties of EPC decrease with further increase in fiber content, due to the insufficient wetting of fibers by epoxy resin which results in poor interfacial bonding. The reinforcing mechanisms of short natural fibers are explored according to the observation of fracture surfaces and micromechanical modelling. It is found that the parallel model based on the rule of mixture can be a good approximation to describe the improvement in flexural strength of the short natural fiber reinforced EPC at low fiber volume fractions.  相似文献   

14.
研究了不同环境下的热处理、湿处理以及等离子处理对Technora纤维力学性能以及表面形态的影响,并初步探讨了其影响规律和机理.研究表明:在本实验测试范围内,经热处理后,Technora纤维的力学性能有一定程度的下降;湿处理时间对纤维的力学性能没有显著影响,随着湿处理温度的升高,纤维的断裂强度有所下降,而断裂伸长有小幅度的提高;等离子处理后,纤维表面有刻蚀,纤维的断裂强度和断裂伸长下降.  相似文献   

15.
通过磁控溅射法在碳纤维表面镀Cu薄膜和Fe薄膜,制得碳/铜复合纤维和碳/铁复合纤维,对其基本性能进行测试分析研究,测试其表面形态、力学性能和浸润性等,并分析不同的溅射工艺条件对纤维的影响,为其产品的进一步开发和应用提供了参考.  相似文献   

16.

为研究混杂纤维增强超高性能混凝土(ultra-high performance concrete, UHPC)的断裂性能, 对带预制裂缝UHPC梁进行了三点弯曲断裂测试, 以研究钢纤维分别与6种非金属纤维混掺对断裂性能的影响. 钢纤维体积分数为1.3%, 混掺合成/无机纤维体积分数均为0.5%. 通过测得荷载-裂缝嘴张开位移(P-D)曲线, 分析了起裂韧度、失稳韧度、断裂能等断裂参数, 研究了切口梁弯曲强度、残余强度等. 试验表明: 混掺纤维UHPC的P-D曲线具有明显的二次强化特性, 钢纤维与其他非金属纤维混掺具有一定的协调阻裂、控裂能力. 混掺合成/无机纤维提高了切口梁裂后的变形能力; 混掺直径为0.15 mm的聚烯烃纤维有利于提高断裂能; 混掺直径为0.04 mm的聚乙烯醇纤维可明显提高UHPC断裂参数; 混掺玻璃纤维有利于提高UHPC抗断裂能力, 其长度不宜大于12 mm; 聚酯纤维的直径不宜大于0.75 mm; 混掺弹性模量较高的非金属纤维更有利于改善UHPC抵抗断裂的能力, 混掺纤维后显著提升了UHPC的断裂能.

  相似文献   

17.
The compressive strength and ilexural toughness as well as fracture energy of fiber reinforced highperformance concrete (FRHPC) subjected to different high temperatures were studied. The results showed that after exposure at 300,600 and 900℃, the concrete mixes retained 88.1% , 41.3% and 10.2% of the original compressive strength on average, respectively. Steel fiber and polypropylene (PP) fiber were both effective in minimizing the damage effect of high temperatures on the compressive strength. The HPC reinforced with steel fibers showed higher flexural toughness and fracture energy before and after the high-temperature exposures. In comparison, PP fibers had minor beneficial effects on the flexural toughness and fracture energy. The mechanical properties of HPC reinforced with hybrid fibers (steel fiber + PP fiber) were equivalent to or better than those of HPC reinforced with steel fibers alone. In addition, the failure pattern of FRHPC beams changed from pull-out of steel fibers at lower temperatures (20, 300 and 600℃) to tensile failure of steel fibers at higher temperature (900 ℃).  相似文献   

18.
The influence of surface state on the moisture sensitivity of carbon fiber was analyzed by applying a T800 grade carbon fiber with five different surface conditions, namely, with and without surface oxidation, in the presence or absence of sizing agent. The interfacial properties of their composites in the presence of two epoxy matrices (respectively EP07 and EP10) were also characterized by micro-droplet tests. The overall results show that both oxidized and sizing-coated fibers have higher moisture equilibrium content than that of the pristine unsurface-treated fiber, due to higher amount of activated carbon groups. After moisture absorption of the carbon fibers, almost all the fiber/epoxy systems show decrease in the interfacial shear strength and the unsurface-treated fiber system exhibits the largest decline. Moreover, both interfacial shear strength and interlaminar shear strength of carbon fiber/EP10 composite demonstrate better water resistance performance than that of the carbon fiber/EP07 composite, consistent with DSC results of the two resins.  相似文献   

19.
为改善芳纶纤维复合材料的界面粘结性能,采用氧气等离子体对芳纶Ⅲ进行表面改性,制备了芳纶环氧复合材料,采用扫描电子显微镜(SEM)、X射线光电子能谱仪(XPS)分析、动态接触角(DCA)分析、测定拉伸强度、弯曲强度等测试方法来研究改性处理效果.结果表明:经等离子处理后,纤维表面m(O)/m(C)比提高,纤维表面粗糙度明显增大,与水的润湿角变小,弯曲强度较未处理提高了30%.  相似文献   

20.
本文探讨了以棉纺流程为基础,应用多种纤维生产混纺纱线,通过以精确称量混合及应用多种混合流程,系统地优化了用棉纺设备生产阳离子易染涤纶、三角形涤纶、有光粘胶等多种纤维混纺纱线的纺纱工艺参数.  相似文献   

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