Study On The Preparation,Structure And Properties Of Alkali-Resistant Phosphate Glass Fibers

Alkali-resistant glass fiber,also known as AR glass fiber,is a reinforcing material used in reinforced concrete and a new green environmental protection material.Not only the alkali-resistant glass fibers have excellent alkali resistance,but also have strong toughness,impact resistance,excellent tensile properties,low elongation,high-temperature flame retardant properties.For now,the silicate alkali-resistant glass fiber component contains a large amount of zirconia,the alkali resistance of the glass can greatly improve by zirconia.However,after the addition of zirconia,the glass melting temperature and the glass forming temperature will increase,which leads to the increase of energy consumption and cost in glass fiber production.Therefore,it is of great significance to study phosphate alkali-resistant glass fibers with excellent alkali resistance and low cost.In this paper,the alkali resistance of two groups of glass samples:10CaO-36Fe₂O₃-54P₂O₅ and 35CaO-12.5Al₂O₃-52.5P₂O₅ are compared,and the sample with better alkali resistance is obtained by comprehensive.Then,the sample doped with rare-earth oxides?La₂O₃ and CeO₂?and metal oxides?TiO₂ and ZrO₂?is studied.Based on DSC,FTIR,SEM,XRD and XRF techniques,and the thermal expansion and high temperature viscosity test,the effects of oxide doping on the structure,density,thermal and chemical properties of phosphate glasses are systematically studied.According to the phosphate glasses doped with different oxide,the following conclusions are drawn:1)The results show that,the sample of 35CaO-12.5Al₂O₃-52.5P₂O₅ has the best alkali resistance,so this glass component is chosen as the basic component in this paper.With the content of La₂O₃ and CeO₂ increase,the network structure of the glass is strengthened,the glass transition temperature T_g and the crystallization temperature T_c value increase,the thermal stability of the glass is improved.According to the chemical stability experiment,the curve of water resistance gradually decreases with the content of La₂O₃ increase from 1.0mol%to 1.5 mol%.The weight loss rate of water resistance is 0.56%when doping with La₂O₃ is 2.5 mol%,and when La₂O₃ is 2.5 mol%,the weight loss rate of alkali resistance is9.62%.Comparing with the two groups,Ce-doped glass has a significant impact on alkali resistance than La-doped.2)TiO₂ acts as a glass network intermediate.TiO₂ enters the glass network as a network forming body in the form of[TiO₄]when the content of"free oxygen"in the glass structure is sufficient.The bond of P-O-Ti-O-P will be formed in the glass network,which transforms the glass network structure from layered or chain-like to frame-like structure.The density of the glass network will be increased,the glass structure will be more stable and the chemical stability will be enhanced.The thermal properties of glass were investigated by DSC methods.It turns out that the value of glass stability increases with the increase of TiO₂ content,and the thermal stability of glass is improved.According to the chemical stability experiment,the weight loss rate of water resistance reaches the maximum when TiO₂ is 0.3 mol%.When the content of TiO₂ is between 0.6 mol%and 1.2 mol%,the curve of water-resistance shows a gradual downward trend,and when the content of TiO₂ is 1.2 mol%,the lowest weight loss rate is 0.49%,which has the best water-resistance.The weight loss rate is 8.11%when the amount of TiO₂ is 0.9 mol%,which has the best alkali resistance.3)ZrO₂ acts as a glass network modifier,the glass network structure will be accumulated when the ZrO₂ is filled into the gap of the glass network.The density and the glass network will be increased due to the large field strength and a large relative molecular mass of zirconium oxide.The T_g and T_c values increase as the addition of ZrO₂ increases,and the thermal stability of the glass increases.ZrO₂ has strong alkali corrosion resistance.When it is doped in phosphate glass,the chemical stability test results show that when the content of ZrO₂ is between 0.3 mol%and 1.2 mol%,the curve of water-resistance shows a gradual downward trend,and when the content of ZrO₂ is 1.2 mol%,the lowest weight loss rate is0.36%,which has the best water-resistance.When the content of ZrO₂ is between 0.6 mol%and 1.5 mol%,the curve of alkali-resistance decreases from 8.41%to 8.09%,and when the content of ZrO₂ is 1.2 mol%,the lowest weight loss rate is 8.06%,which has the best alkali resistance.Based on the above research,the glass with excellent alkali resistance is tested for drawing performance,and the results show that it can be drawn into glass fiber.