高性能纤维作为橡胶骨架材料的应用研究

研究聚酰亚胺纤维、芳纶纤维、玄武岩纤维、聚萘二甲酸乙二醇酯(PEN)纤维和聚亚苯基苯并二噁唑(PBO)纤维的工业丝性能及浸胶帘线的力学性能和粘合性能。结果表明:聚酰亚胺纤维和PBO纤维具有较高的强力和模量;聚酰亚胺纤维通过参考芳纶纤维的浸胶液配方进行浸胶处理,帘线与橡胶粘合性能良好;PEN纤维可以直接使用聚对苯二甲酸乙二酯(PET)纤维的浸胶方法进行处理;玄武岩纤维采用优化浸胶液配方进行浸胶处理,完全可以实现帘线与橡胶的良好粘合;PBO纤维采用目前现有浸胶方法较难进行表面接枝处理,与橡胶粘合性能较差。     

高模碳纤维M40/聚酰亚胺预成型膜层合复合材料的研究

采用膜层压方法,制备了单向高模碳纤维增强共聚聚酰亚胺复合材料;考察了共聚聚酰亚胺结构、纤维表面处理和成型工艺对复合材料性能的影响.结果表明膜层压复合材料的孔隙小,力学性能高,分子链柔顺的聚酰亚胺复合材料的力学性能高;纤维表面处理对复合材料的层间剪切强度影响不大;成型温度对复合材料的力学性能有显著的影响.     

聚酰亚胺纤维增强环氧树脂结构透波复合材料的性能研究及机制分析

选择聚酰亚胺纤维和环氧树脂,采用热熔法制备出了聚酰亚胺/环氧结构透波复合材料。通过傅里叶变换红外光谱、吸湿率、力学性能、介电性能、湿热老化性能以及扫描电子显微镜等表征手段,研究了聚酰亚胺/环氧结构透波复合材料的结构透波性能和耐湿热环境性能。研究结果表明：聚酰亚胺纤维中刚性共轭结构赋予了聚酰亚胺纤维复合材料良好的透波性能和耐湿热性能,但是与石英纤维增强环氧树脂复合材料相比,聚酰亚胺纤维增强环氧树脂结构透波复合材料仍存在着压缩强度、弯曲强度与层间剪切强度低、吸湿率高的问题;力学性能破坏模式分析结果显示,聚酰亚胺纤维同时存在有机纤维的吸湿、压缩强度低、纤维/树脂界面结合差的问题。     

湿法造纸技术制备聚酰亚胺纤维增强体及其对热塑性树脂基复合材料力学性能的影响

利用湿法造纸成形技术抄取得到聚酰亚胺纤维纸,分别以等质量的聚酰亚胺纤维、聚酰亚胺纤维纸为增强体,采用手糊成型、热压法制备热塑性聚酰亚胺树脂基复合材料。聚酰亚胺纤维纸增强体改变了纤维的存在形式,解决了复合材料中纤维束多、纤维孔径分布不匀、有效长度低、材料力学性能不佳等问题,纸增强复合材料拉伸性能提高130%,弯曲性能提高108%,层间剪切性能提高34.5%。聚酰亚胺纤维纸增强体自身因素影响了复合材料力学性能,从纤维长度、打浆状况、纸页定量角度分析了复合材料力学性能改善的原因。     

表面处理对碳纤维束拉伸性能与强度分布的影响

为了探究表面处理工艺对C纤维束拉伸性能的影响,采用化学气相沉积(CVD)制备热解炭(PyC)层和热处理以及两者相结合的方法对C纤维束进行处理,并测试了处理前后C纤维束的拉伸性能和强度分布。实验结果表明:在C纤维表面沉积PyC层降低了纤维束的拉伸性能与强度稳定性。对C纤维束进行热处理改善了纤维束的拉伸性能和强度稳定性,并在1 800℃均达到了最大值。随着热处理温度的升高,C纤维束的拉伸断裂方式逐渐由韧性断裂向脆性断裂转变。采用沉积PyC层以及沉积PyC层和热处理相结合的方式处理的C纤维束均以脆性方式断裂。     

热处理工艺对三元共聚聚酰亚胺纤维结构和性能的影响

采用傅立叶红外光谱(FTIR)、扫描电子显微镜(SEM)、声速取向、热重分析仪(TGA)等表征手段研究了热处理对湿法纺丝制备的3,3’,4,4’—二苯酮四酸二酐(BTDA)—二异氰酸甲苯酯(TDI)/二异氰酸二苯甲烷酯(MDI)三元共聚聚酰亚胺纤维结构与性能的影响。结果表明:热处理对纤维结构无明显影响;热处理使纤维表面更加致密,提高了纤维的取向度;与初生纤维相比,热处理之后纤维力学性能提高了近3倍,模量提高了2倍,同时热稳定性能得到了增强。     

短切聚酰亚胺纤维增强混凝土性能

通过酸洗、化学接枝的方法对短切聚酰亚胺纤维进行表面改性，并对不同配比的短切聚酰亚胺纤维增强混凝土进行了相关性能研究。结果表明，硅烷偶联剂成功接枝到聚酰亚胺纤维表面，并且改性后的聚酰亚胺纤维能够提高纤维在混凝土内的分散性，并对混凝土性能有较为明显的提升作用，w(改性聚酰亚胺纤维)=0.8%,混凝土的综合性能达到最优值。     

硅橡胶与骨架材料的粘合性能研究

研究硅橡胶与聚酰亚胺纤维织物、聚酰胺纤维织物、聚酯纤维织物、玻璃纤维织物、聚四氟乙烯及金属等骨架材料的粘合性能。偶联剂VTPS、开姆洛克608、偶联剂KH-550/A-151并用体系和偶联剂A-151/间苯二酚并用体系是硅橡胶与骨架材料的良好粘合剂,能有效提高硅橡胶与聚酰胺纤维织物、聚酯纤维织物、玻璃纤维织物、聚四氟乙烯、不锈钢和铝合金的粘合强度。在骨架材料表面处理胶浆中,粘合剂含量为10%,硅橡胶与骨架材料的粘合强度较高,粘合剂增粘效果较佳。聚酰亚胺纤维类织物与硅橡胶的粘合性能很差,只有使用开姆洛克608作表面处理胶浆粘合剂,聚酰亚胺纤维织物与硅橡胶才可获得良好的粘合性能。     

石英纤维的表面处理工艺对其性能的影响

通过溶剂处理及其与热处理相结合的方法去除石英玻璃纤维表面的浸润剂,对石英纤维表面处理前后的状态变化及其拉伸性能进行了研究,结果表明:单独采用溶剂处理纤维编织体的失重为0.77%,经高温处理后纤维略带黄色,拉伸强度下降明显,逐步趋向变脆并粉化,在复合材料中失去了增强的效果,而采用溶剂+热处理工艺处理后纤维的失重为1.64%,热处理后纤维呈亮白色,不仅可较完全的去除浸润剂,而且还可以使石英纤维本身强度受损较少,可起到增强复合材料的效果。     

封端异氰酸酯合成聚酰亚胺及其性能

以苯甲醇封端的甲苯二异氰酸酯、苯甲醇封端的二苯甲烷二异氰酸酯和3,3',4,4'-二苯酮四酸二酐为原料制备聚酰亚胺,并在高温条件下进一步热处理提高其相对分子质量。采用傅里叶变换红外光谱、热重分析、差示扫描量热法等研究了其结构和性能。结果表明:在250℃处理5 h,然后350℃处理2 h后,成功制备了具有较好热性能和较高相对分子质量且具有良好溶解性能的聚酰亚胺。     

一步法聚酰亚胺纤维的制备及其性能研究

利用实验室自制的聚酰亚胺(P)I溶液,通过干湿法纺丝制得PI初生纤维。在以水和N-甲基吡咯烷酮(NMP)混合溶液(体积比8∶2)作为凝固浴,凝固浴温度为5～15℃的条件下,所得初生纤维结构均匀密实,纤维截面呈圆形或腰圆形。在对初生纤维进行热处理时,随着热处理温度升高和时间增加,PI纤维的力学性能增强。当热处理温度为300～320℃、时间为30 min时,PI纤维的力学性能最优,其断裂强度和初始模量达到2.474 cN/dtex和50.066 cN/dtex;当热处理温度高于320℃,时间超过1 h,纤维力学性能又缓慢下降。纤维的热稳定性较好,在500℃左右仍具有较好的热稳定性。     

聚酰亚胺初生纤维存放过程中结构与性能的变化

采用传统二步法合成部分成环的聚酰亚胺预聚体,经湿法纺丝得到聚酰亚胺初生纤维,探讨了纤维结构与性能随存放时间的变化。结果表明:室温下聚酰亚胺初生纤维的强度与模量随存放时间的延长明显降低,但在-15℃下,力学性能基本保持不变。初生纤维在室温下存放60d,其热分解温度从567.1℃降到了558.0℃。低温下放置可抑制初生纤维力学性能的衰减。     

热塑性聚酰亚胺的热膨胀系数研究

利用静态热机械分析仪（TMA）测定了热塑性聚酰亚胺（TPI）注塑件的热膨胀系数α，考察了TPI的各向异性、尺寸稳定性以及添加不同填料对α的影响。结果表明：TPI存在着各向异性，且流向面的α最低。在正常的使用范围内，试样经历一个升降温循环后尺寸基本没发生变化。经消除热历史后，材料的α降低；类似地，热处理也能使。减小。在主链相同的TPI树脂中，加入玻纤、碳纤维等高强度、高热稳定性的填料有助于降低TPI的α。     

制备条件对聚酰亚胺中空纤维膜性能影响的研究进展

综述了内部和外部凝固剂的化学性质、凝固浴温度等对聚酰亚胺（PI）中空纤维的形态和对PI中空纤维膜的气体分离,性能的影响。同时,叙述了纤维塑化抑制和亚胺化条件控制等对提高PI中空纤维膜分离性能的作用.     

Tribological behavior of short‐fiber‐reinforced polyimide composites under dry‐sliding and water‐lubricated conditions

Polyimide composites reinforced with short‐cut fibers such as carbon, glass, and quartz fibers were fabricated by the polymerization of monomer reactants process. The mechanical properties of the composites with different fiber contents were evaluated. The friction and wear properties of the polyimide and its composites were investigated under dry‐sliding and water‐lubricated conditions. The results indicated that the short‐carbon‐fiber‐reinforced polyimide composites had better tensile and flexural strengths and improved tribological properties in comparison with glass‐fiber‐ and quartz‐fiber‐reinforced polyimide composites. The incorporation of short carbon fibers into the polyimide contributed to decreases in the friction coefficient and wear rate under both dry and water‐lubricated conditions and especially under water lubrication because of the boundary lubrication effect of water. The polyimide and its composites were characterized by plastic deformation, microcracking, and spalling under both dry and water‐lubricated conditions, which were significantly abated under the water‐lubricated condition. The glass and quartz fibers were easily abraded and broken; the broken fibers transferred to the mating metal surface and increased the surface roughness of mating stainless steel, which led to the wear rate increasing for the glass‐fiber‐ and quartz‐fiber‐reinforced polyimide composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Thermotropic liquid crystal polymer fabric reinforced polyimide composite materials

An aromatic copolyeste thermotropic liquid crystal polymer (LCP) fabric was used to reinforce a polyimide (PI) matrix to produce composites. The LCP/PI composite was made to eliminate directional difference in the mechanical properties of LCP by controlling the individual reinforcement fabric alignment in different directions without losing any mechanical properties. As a result, a transversely isotropic LCP composite material could be obtained from the highly anisotropic LCP fiber. Interfacial adhesion between the LCP and polyimide was greatly improved by a NH₃/H₂ plasma treatment on the LCP fabric, thereby the significantly improving mechanical properties of the composite. Moreover, inter‐laminar shear strength of the LCP/PI composite was further increased after heat treatment at 220°C for 1 hour. The LCP/polyimide composite retains stable mechanical properties up to 250°C.     

Preparation and properties of nadic‐end‐capped cyclotriphosphazene‐containing polyimide/carbon fiber composites

New novel fire‐resistant and heat‐resistant cyclotriphosphazene‐containing polyimide resins were prepared in situ by the polymerization of (p‐aminophenoxy)(phenoxy)cyclotriphosphazenes with 3,3′,4,4′‐benzophenonetetracarboxylic acid or 3,3′,4,4′‐diphenylsulfonetetracarboxylic acid and a crosslink agent, 5‐norbornene‐2,3‐dicarboxylic acid and were used as polymer matrix compositing with a woven carbon fiber to prepare nadic‐end‐capped cyclotriphosphazene‐containing polyimide/carbon fiber composites. The thermal stability, flame retardance, morphology of the surface fracture, and some physical properties of the composites were investigated by thermogravimetric analysis, scanning electron microscopy, and a material testing system, respectively. The composites had good thermal stability, flame retardance, and mechanical properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 810–818, 2003     

高强高模聚酰亚胺纤维与对位芳纶的综合性能研究

对高强高模聚酰亚胺(PI)纤维与对位芳纶(PPTA)的形貌特征、吸湿性能、热性能(热尺寸稳定性能与耐高温性能)和耐候性能(耐水解性能与抗紫外光老化性能)进行了研究。结果表明:与PPTA纤维相比,高强高模PI纤维表面呈现明显的沟槽结构,断面没有出现明显的劈裂和原纤化现象;PI纤维吸湿率仅为PPTA纤维的1/6,且具有更高的热尺寸稳定性,在350℃下具有稳定的力学性能,在耐酸性、耐高温水解性以及抗紫外老化性能方面表现优异,但PI纤维耐碱性能弱于PPTA纤维。     

The effect of carbon fiber content on the friction and wear properties of carbon fiber reinforced polyimide composites

The current study examines the tribological performance of polyimide and carbon fiber reinforced polyimide (CF/PI) under dry sliding condition. Different contents of carbon fibers were employed as reinforcement. All filled and unfilled polyimide composites were tested against CGr15 ball and representative testing was performed. The effects of carbon fiber content on tribological properties of the composites were investigated. The worn surface morphologies of neat PI and its composites were examined by scanning electron microscopy and the wear mechanisms were discussed. Moreover, all filled polyimides have superior tribological characteristics to unfilled polyimides. The optimum wear reduction was obtained when the content of carbon fiber is 20 vol %. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008