PBO纤维水解降解机理探讨

PBO纤维是非常强的合成纤维,是新一代的超高技术纤维,具有极好的力学性能和热性能,非常好的模量、强度和极强的耐化学品性,这些性能使PBO纤维成为高技术用的最佳材料。制造工艺对它的力学性能影响很大。PBO在高温和高相对湿度下将发生水解降解,压缩了它的应用范围。了解降解机理及其影响因素,对于更好地利用PBO是极为重要的。     

复合抗紫外剂对PBO纤维光稳定性的影响

通过在聚合过程中同时添加有机紫外吸收剂UVA和UVP的方法制备了PBO聚合物,并通过干喷-湿纺工艺制备了含紫外吸收剂(UVA+UVP)的PBO纤维。考察了纤维的力学性能、特性粘度及表面形貌在紫外老化过程中的变化,结果表明,单独添加紫外吸收剂UVA能改善PBO纤维的紫外稳定性,而添加紫外吸收剂(UVA+UVP)则使PBO纤维的紫外稳定性进一步提高,并且都未给聚合和纺丝带来不利影响。     

氧等离子体处理对PBO纸页性能的影响

研究了PBO(聚对苯撑苯并双噁唑)浆粕在氧等离子体不同处理条件下对PBO纸页性能的影响.实验结果表明,氧等离子体处理是PBO浆粕十分有效的改性手段;经过氧等离子体处理后,PBO浆粕增加了活性基团,从而改善了浆粕的分散性能,提高纸页匀度;同时,PBO纸页的强度也有大幅度提高,裂断长从3.5 km提高到5.7km,撕裂指数从4.36 mN·m2/g提高到6.47mN·m2/g,耐破指数从4.78 kPa·m2/g提高到5.97 kPa·m2/g.     

Crystallographic texturing in single poly(p-phenylene benzobisoxazole) fibres investigated using synchrotron radiation

A micro-focus synchrotron beam has been used to investigate crystallographic texturing in poly(p-phenylene benzobisoxazole) fibres. By generating diffraction patterns across single fibres, it is possible to produce profiles showing scattering intensity as a function of beam position across the fibre. A straightforward model has been developed to allow the degree of texturing to be quantified for direct comparison between fibre types. The experimental results are found to fit a radial fibrillar-texturing model, which incorporates a distribution in radial orientation about the fibre axis. Previous studies reporting the a-axis of the PBO unit cell to be aligned radially within fibrils about the fibre axis are found to be correct.The degree of radial fibrillar texturing is in the same fibre order as tensile modulus and crystalline domain orientation for PBO fibres with different processing histories. It is proposed that the degree of radial fibrillar texturing is therefore related to fibre homogeneity. An extrapolation of tensile modulus to that of a perfectly homogeneous fibre results in a value in good agreement with the PBO crystal modulus. This further supports the proposal that the degree of radial fibrillar texturing is related to fibre homogeneity.     

表面处理对环氧树脂/PBO纤维界面剪切强度的影响

采用了磺化聚芳酰胺(SPA)和固化剂593分别对PBO纤维进行表面处理,用钢针将配好的环氧树脂基体溶液似微球状滴在固定在试样架上的PBO纤维上,考察了处理前后PBO纤维与环氧树脂界面剪切强度的变化。结果表明,两种表面处理对PBO纤维与环氧树脂基体的界面剪切强度都有贡献,其中固化剂处理能显著提高界面剪切强度,改变了界面破坏模式,使PBO纤维与环氧树脂基体的界面剪切强度最高可达19.41 MPa,比未处理时的界面剪切强度提高95%。     

PBO 纤维表面改性研究进展

简要介绍了聚苯并双恶唑(PBO)纤维的结构与性能,综述了利用等离子体、γ射线、化学试剂、超临界流体以及生物载体等进行表面改性的方法,分析了各种方法的优劣并对 PBO 纤维的应用前景进行了展望。指出利用这些介质对 PBO 进行表面处理各有利弊,因此 PBO 纤维的表面处理由以前的单一、间歇性的化学改性方法逐步向连续的、在线的以及多种手段共用的复合处理方向发展。     

Surface Modification of PBO Fibers for Composites by Coaxial Atmospheric Dielectric Barrier Discharge (PLA-PLA)

In this work, the surface modification of poly (1, 4-phenylene-cis-benzobisoxazole) (PBO) fibers by O 2 /Ar coaxial atmospheric dielectric barrier discharge was investigated, as well as the interfacial adhesion properties of modified PBO fibers/epoxy composites. The results indicated that the contact angle decreased remarkably from 84.7 to 63.5 after 3 min O 2 /Ar plasma treatment. SEM and AFM images showed that the surface of the treated PBO fibers became rather rough. In addition, XPS results suggested that the polar functional group (O=C- O) was introduced on the surface of the treated PBO fiber. The interfacial adhesion test showed that the interfacial shear strength (IFSS) and the interlaminar shear strength (ILSS) increased significantly by 63.54% and 130%, respectively. Moreover, the excellent tensile property of the PBO fibres was well preserved     

导电PBO织物的制备及其吸波性能

以离子注入法制备了导电聚对苯撑苯并二噁唑(PBO)织物,并对其表面形貌、结构和导电性能进行了表征。以导电PBO织物制备了频率选择表面(FSS),研究了FSS对纳米碳纤维(CNF)复合材料吸波性能的影响。     

Improvement of interfacial shear strengths of polybenzobisoxazole fiber/epoxy resin composite by n‐TiO2 coating

Smooth polybenzobisoxazole (PBO) fiber has limited interfacial interaction with resin matrix. In this article, nano‐TiO₂ coating on PBO fiber is applied to improve the interfacial adhesion between PBO fiber and epoxy resin. The test results suggest that the PBO fiber had good interaction with epoxy resin matrix after its treatment with n‐TiO₂ sol. Nano TiO₂ particle embedded onto PBO fiber surface, acting as a chock, which made fiber implanted into the resin better. This greatly improved the shear strengths (IFSS) of PBO fiber/epoxy resin composite. It has been found that a 56% increase in interfacial IFSS has achieved without sacrificing mechanical properties of fiber. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

The tribological properties of poly(p‐phenylene benzobisoxazole) pulp reinforced friction materials

Automotive friction materials reinforced by home‐made poly (p‐phenylene benzobisoxazole) (PBO) pulp (fibrillated organic fibers) were prepared through compression molding. The friction and wear behaviors of the obtained composite materials were evaluated using a constant rotating speed type friction tester. The PBO pulp content and the testing loads showed clear influence on the tribological properties of the composites. Friction stability, wear rate, and morphology of sliding surfaces were carefully examined to investigate the effect of the pulp ingredient in the friction materials. Scanning electron microscopy was employed to study the morphology of the surface and wear particles. The significant wear reduction was achieved when the mass fraction of PBO pulp was 3%. Wear rates of the composites with 3% PBO pulp were measured over a load range from 0.3 to 1 MPa at different temperatures. The results pointed to two facts: (1) the wear rate of the friction material increased linearly with load at low temperature (below 200°C); (2) wear status varied with the testing loads at high temperature (above 250°C). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4032–4039, 2013