SiO2-Al2O3-MgO系高强玻璃纤维耐酸性能研究

采用高温熔融法制备了SiO2-Al2O3-MgO系统的S级高强玻璃纤维,研究了不同玻璃组分对玻璃耐酸性能的影响,利用扫描电镜(SEM)、红外光谱(IR)和核磁共振(NMR)等手段分析了酸侵蚀前后纤维的表面形貌和微观结构,进而分析了S级高强玻璃纤维在酸腐蚀环境下的破坏机理.结果表明:S高强玻璃的结构主要由硅氧四面体SiO4]和铝氧四面体AlO4]等构成,随着酸蚀的进行,玻璃网络结构被破坏,Si-O-Si断裂形成Si-OH键并形成凝胶附着在纤维表面;而铝氧多面体中Al-O键断裂,Al3+逐渐从玻璃结构中被置换出来,导致玻璃网络中Al3+浓度大大降低;高强系列玻璃的耐酸性能与玻璃表面的化学组成以及玻璃内部的微观结构关系密切.致密的玻璃网络结构有利于抑制H+对玻璃结构破坏,抑制阳离子与H+的置换作用;此外引入离子场强高的Ti4+,由于"积聚"作用而使玻璃结构致密,提高玻璃纤维的耐酸性.

Acid Resistance Properties for SiO2-Al2O3-MgO System High Strength Glass Fibers

High Strength glasses fibers with different compositions were prepared by conventional melting method. The relationship between the composition and acid resistance properties was researched. The variation of glass fibers in surface and structure was investigated using scanning electron microscope (SEM),infrared spectrometer (IR),nuclear magnetic resonance (NMR)before and after acid etching. The IR and NMR results indicate that the glass network structure is mainly consisted of SiO4 ] tetrahedron and AlO4 ]tetrahedron. After acid etching the silicon-oxygen bond (Si-O-Si)and the aluminum-oxygen bond (Al-O)in network structure would be broken. The Si-O-Si bond reacted to form Si-OH bond and finally attached to the fiber surface by transforming into silica gel,while the Al3+ would be replaced by hydrogen ion (H+)from solution so that the concentration of Al3+ in glass network is reduced. The relevance between composition and acid resistance properties shows that the slightly increasing of glass network former and high field strength modifier ion will strengthen the glass network and improve the acid resistance properties. High degree of polymerization will make migration of ions difficult and restrain the replacement reaction. Besides,stronger bond between high field strength ion Ti4+ and the anions groups corresponds to higher degree of polymerization,and better acid resistance properties.