Study On Composition And Properties Of Boron-fluorine-free Fiberglass

Fiberglass is one kind of new functional materials and the structural material,which has been applied in the electron, communication, nuclear power, aviation, astronautics, weapon and other high-end areas for a series of outstanding characteristics. Fiberglass becomes the essential high technology material for sustainable developments in 21st century. At present the produced continuous glass fibers above 90% is E glass. Boron and fluoride evaporate in the form of fluoride acid, hydrofluoric acid and fluorine borate in E glass-melting process, which not only affect the uniformity of glass composition and performance, but also pollute the environment. Now reducing boron-fluoride evaporation becomes the focus of attention.Based on the analysis of the situation at home and abroad, structure,basic properties and processing properties of Boron-fluorine-free glass fibers was studied. In this thesis, series of Boron-fluorine-free glasses that CaO was replaced by MgO, TiO₂, ZnO respectively in the same moore number were prepared via a usual melting and quenching technique in the air medium. A number of studies differential infrared spectra (IR), nuclear magnetic resonance were used to analyze the structure of glass, chemical resistant, density, dielectric constant, glass fiber process have been carried out to explain the relation between glass structure and dielectric properties. Based on this, the study got optimal formula of boron-fluorine-free glass fiber by design optimization.The study of boron-fluorine-free glassfiber based system for doping metal oxide MgO. IR spectra and NMR analysis showed that Al³⁺ isn't fully into the glass network structure, part Al³⁺ exists in the network structure in the form of [AlO₆]. As 1.5mol % MgO introduced, the rest Al³⁺ enters the network structure.Glass network structure firstly increase then decrease, the glass density increase, the chemical durability improve ,dielectric constant and loss decrease after adding more MgO. Devitrification temperature and fiber-forming temperature firstly decreases then increases. The substituted amount of MgO increased from 3mol% to 6mol% is accord with glass fiber drawing technology requirements.The study of boron-fluorine-free glass fiber based system for doping transition metal oxides TiO₂ and ZnO respectively.â‘ IR spectra shows that when the substituted amount of TiO₂ increased from 1.5mol%-3mol%, Ti4+enters the glass network as a modifier; but for 4.5 mol%, Ti⁴⁺ enter the glass network in form of [TiO4].The extreme unstability of Ti⁴⁺ is significant when TiO₂ is increased at 6mol%. Glass network structure firstly increases then decreases by doping TiO₂; the glass density increases; dielectric constant and loss firstly decreases then increases; the glass chemical durability increases after more TiO₂was added. Devitrification temperature firstly decreases and then increases, however fiber-forming temperature gradually reduced. The substituted amount of TiO₂ increased from 1.5mol% to 3mol% is accord with glass fiber drawing technology requirements.â‘¡IR spectra shows that Zn²⁺ enters the glass network as a modifier when the substituted amount is7.5mol%. Glass network structure increases by doping ZnO; the glass density increases; dielectric constant firstly decreases then increases, however dielectric loss decreases; the glass chemical durability improves. Devitrification temperature firstly decreases and then increases, however fiber-forming temperature gradually reduced. The substituted amount of ZnO increased from 1.5mol% to 4.5mol% is accord with glass fiber drawing technology requirements.From the experimental result above, the interaction of MgO, ZnO and TiO₂ to boron-fluorine-free glass fiber was investigated. The best formula was obtained.