环氧树脂/PBO纤维复合材料性能研究

对环氧树脂(EP)/聚对苯撑苯并二恶唑(PBO)纤维复合材料的性能进行初步研究。结果表明,用浓度70%的甲基磺酸(MSA)溶液对PBO纤维表面进行处理,可改善PBO纤维与EP基体的粘结强度,但同时使PBO纤维的拉伸性能降低;对PBO纤维处理2h后,以胺类固化剂固化的EP/PBO纤维复合材料的层间剪切强度比处理前提高41%,以酸酐固化剂固化的EP/PBO纤维复合材料的层间剪切强度比处理前提高48%;前者的层间剪切强度大于后者。     

Improving high-altitude UV–Vis resistance of PBO braided tendons of NASA’s super pressure balloons

Super pressure balloons (SPBs) are used by the National Aeronautics and Space Administration (NASA) for ultra-long duration ballooning (ULDB) missions which carry various scientific explorations to support space and earth sciences research activities. The resistance to photo-degradation of load-bearing braided tendons of SPBs is critical to the success of ULDB missions. Recognizing the critical need to improve UV and visible light (UV–Vis) protective performance of p-phenylene-2, 6-benzobisoxazole (PBO) braids, North Carolina State University and NASA's Balloon Program collaborated to investigate the effectiveness of sheath extrusion method in improving the UV–Vis resistance of tendons. This study included two PBO tendon types – 48,000 (48k) denier tendons and 72,000 (72k) denier tendons. Using a sheath extrusion method, the tendons were covered with UV protective sheath of low-density polyethylene containing two types of UV inhibitors – TiO₂ rutile nanoparticles and PolyOne PE White CC^®. Bare and sheathed tendons were subjected to artificial UVB exposure in the lab as well as to both high altitude and ground exposure during flight missions conducted by NASA. Protection against radiation exposure was evaluated by determining the loss of tensile strength after exposure. UV–Vis protection of tendons improved with an increase in sheath thickness as well as UV inhibitor content in the sheath. The results also showed that 72k denier braids had higher resistance against UV degradation compared to 48k denier braids. In-flight exposure results confirmed the comparative UV protective performance of tendons exposed to accelerated artificial UVB exposure in lab. 72k denier tendon covered with sheath containing 10% PE White CC^® (sheath thickness of 0.37 mm) experienced the lowest strength loss among all tendon samples to high-altitude exposure during flight missions. The study has also utilized UV–Vis transmittance of the sheath covering the braids as a method of evaluating the performance of the protective sheaths.     

PBO纤维表面超声化学处理工艺及作用机理

研究了多聚磷酸无水乙醇溶液和超声波附加作用处理聚对苯撑苯并双口恶唑(PBO)纤维表面的工艺。利用扫描电镜和纤维电子强力仪等评价了表面处理后PBO纤维的表面形貌、拉伸强度以及与环氧树脂的界面结合性能等,探讨了PBO纤维超声化学表面作用机理。结果表明,当多聚磷酸与无水乙醇体积比为1∶1、超声设备功率54W、反应时间4min时,PBO纤维的表面处理均匀,与原丝相比,单丝拉伸强度只降低了5.7%,而单丝拔出强度则提高了67.2%。超声波的空化作用导致溶液中多聚磷酸分子分散均匀性提高、羟基自由基含量增加,以及纤维表面粗糙度提高,是PBO纤维表面处理质量改善的主要原因。     

The effects of coagulants on the structure of PBO materials

PBO(poly(p-phenylene benzobisoxazole)),arigid-rod polymer containing an aromatic hetero-cyclicring,is characterized by high tensile strength,highstiffness,high thermal stability and other super proper-ties.It can be easily processed into fiber and film foruse in such fields as aerospace application,high tem-perature electrical insulation parts and protective gar-ments and so on[1-3].PBO materials are usually pre-pared through several steps in which polymerization,spinning or filming and coagu…     

PBO纤维应用于高强度微型光缆的可行性研究

介绍了当前高强度微型光缆的结构,及其加强材料的性能。首先提出了将超高性能牌号为Zylon的PBO纤维(含有芳香杂环的聚苯唑聚合物)作为微型光缆抗拉元件的加强材料的设想,并将其与芳纶(芳香族聚酰胺纤维)、高强度玻璃纤维、钢丝等加强材料的性能作了比较,提出了应用的初步设想,得出了Zylon纤维将成为目前最好的高强度微型光缆加强材料的结论。     

PBO纤维光稳定性研究

研究了聚苯撑苯并二噁唑（PBO）纤维在自然环境中的光稳定性。PBO纤维对可见光和紫外光都十分敏感,波长范围400～450 nm的可见光即可导致PBO纤维力学性能下降,而波长范围200～400 nm的紫外光可以加速PBO纤维的老化过程,同时自然环境中温度、湿度的变化将会进一步加速PBO的光老化。PBO纤维经自然湿热老化3...     

PBO纤维及复合材料研究进展

介绍了聚对苯撑苯并二恶唑(PBO)纤维国内外研究概况,综述了PBO纤维复合材料的研究概况及应用领域,并对今后PBO纤维复合材料的发展做出展望.     

PBO纤维表面改性的研究进展

聚对苯撑苯并双噁唑(PBO)由于其特殊的表层结构,与聚合物树脂基体复合时存在严重的界面不相容性。简要介绍了PBO纤维的结构与性能,综述了化学刻蚀、偶联剂处理、等离子体处理、电晕处理、辐射处理、酶处理、热处理、化学涂层和超临界液体处理等PBO纤维表面改性方法。     

Effect of Surface Modification on Mechanical and Tribological Performance of Poly-p-phenylenebenzobisoxazole Fiber-Reinforced Polyimide Composite

This work examined the effect of coupling agent surface modification of Poly-p-phenylenebenzobisoxazole (PBO) fibers on mechanical and tribological performance of PBO fiber-reinforced thermoplastic polyimide (PBO/PI) composites. The results show that tensile strength and flexural strength are largely improved by coupling agent treatment. Under dry sliding conditions, coupling agent treatment is effective to reduce the wear of PBO/PI composite. The principle of improvement in interfacial adhesion between PBO fiber and PI matrix after coupling agent treatment was discussed. The surface characteristics of PBO fibers were characterized by X-ray photoelectron spectroscopy (XPS). It is found that the content of polar groups on the surface of PBO fiber treated by coupling agent increases compared with the untreated fiber. The presence of polar groups is probably leading to an increment of interfacial binding force between fibers and matrix in a composite system, and accordingly enhances the mechanical and tribological properties.     

聚苯并噁唑(PBO)的合成及其应用研究

聚苯并噁唑(PB0)因其具有的强度大、耐高温、耐氧化、耐潮湿以及优良的热稳定性等特点，自20世纪80年代以来一直是人们关注的热点之一。综述了PB0的合成方法，如多磷酸法、中间相聚合法、三甲基硅烷基化法、对羟基苯甲酸酯法，并介绍了PB0纤维的性质，对其应用前景作了展望。