Study On The Surface Modification And Performance Of PBO Fiber

Poly-p-phenylenebenzobisthiazole(PBO)fiber is a kind of polyamide fiber containing heterocyclic aromatic and PBO fiber is usually processed by the method of liquid crystal spinning.PBO fiber is reputed as the super fiber in 21st century for its great mechanical and physicochemical properties.Therefore,PBO fiber has been widely used in a variety of engineering applications,such as aerospace,automation,national defense and architecture.But the structure of PBO fiber will be damaged and degraded quickly after a long time of ultraviolet irradiation.Meanwhile,the surface of PBO fiber is lack of active group and too smooth to combine with matrix well.Above mentioned two defects restrict the application of PBO fiber.To enhance PBO fiber's UV resistance and surface activity,we adopted methods of magnetron sputtering,hydro-thermal synthesis and chemical vapor deposition orderly modifying PBO surface.Obtained PBO/TiO2,PBO/ZnO and PBO/silicon microtube fibers were characterized and tested to investigate modified fibers' properties.Firstly,low-temperature plasma was used to pretreat PBO surface so as to introduce active groups and enhance roughness of PBO surface due to its surface inert.Experiment results showed that when the power of plasma enhancement,length of treating time and oxygen flow were set as 120W,6min and 30 sccm,respectively,PBO fiber would keep the highest retention rate of mechanical property as the active groups and rough surface were obtained.Then we immediately adopted above mentioned methods to prepare PBO/TiO2,PBO/ZnO and PBO/silicon microtube composite fibers.Experiment of ultraviolet accelerated aging showed the modified fiber all had higher UV resistance than the original fiber.After the different UV irradiating time,retention rate of mechanical property of three types of composite fiber was increased by 27.47%,28.06%and 7.58%,respectively.Meanwhile,we made a simple examination for the mechanism of UV resistance.Changes of fiber's surface structure also effected other properties of fiber.For example,the interfacial shear strength with resin matrix achieved a great improvement and modified fiber has hydrophobic properties.IFSS of PBO/ZnO fibers was increased from 13.56MPa to 21.07MPa,meanwhile contact angle and roll angle of fiber's surface are 144.02° and 23.5°,respectively.For PBO/silicon microtube fibers,IFSS was increased from 13.56MPa to 24.10MPa,the contact angle was over 150° and showed super-hydrophobicity,meanwhile its roll angle was about 18°.We also did research of stability of acid,alkali,solvent and UV resistance aim at surface wettability of PBO/ZnO fibers and PBO/silicon microtube fibers.Results showed the composite fiber had good stability after above treatments.We adopted methods of Fourier Transform Infrared Spectroscopy(FTIR),Scanning Electron Microscope(SEM),Energy Dispersive Spectrum(EDS)and Thermogravimetric Analysis(TGA)to measure the modified fibers.The results showed that TiO2 coating,ZnO nanostructure and silicon microtubes were sputtered,grown and grown by the way of self-assembly on PBO surface.Above structure arranged on fiber surface uniformly,and it introduced changes of morphology,structure,elementary composition,thermal stability and crystal form.Compared with original fibers,properties of modified fibers were getting better.PBO fiber was endowed ultraviolet resistance,hydrophobicity,higher interfacial shear strength and so forth through above three methods.And its application field was broadened.Functionalization and intelligentize of PBO fiber is essential and potential.And this work must be valuable in the future.