| Nowadays, more and more new materials and production technologies appear in the research production of building materials, among which FRP(Fiber Reinforced Polymer) bars are one of modern new high performance building materials. In the concrete structure, FRP bars are the best choice to replace steel due to that FRP bars have better durability, lighter weight, higher tensile strength, better corrosion resistance than the traditional steel.FRP bars have not been widely used at home and abroad, and their long-term durability performance was studied less. However, with abundant artificial accelerated tests, researchers realized that the effect of external environment to the FRP bars’ performance is unneglected. Given this, a good durability performance coating was prepared by waterborne epoxy resin and mixed etherification melamine resin, and it formed a layer of protective film to protect FRP bars from the erosion of the external environment. The main research content is as follows:(1) On the basis of synthesis of mixed etherification melamine resin by wet method, the eco-friendly high-etherification melamine formaldehyde resin was prepared through dry method with low formaldehyde, high solid content and high stability. Meanwhile, the factors such as ratio of the material in each reaction stage, temperature and p H, were discussed to confirm the optimal preparation conditions. The results indicate that, when n(melamine) : n(formaldehyde) = 1:10, reaction temperature was 75 ℃, p H was 9.0, the reaction time was 50 min in the hydroxymethylation reaction stage, and when n(HMM) : n(alcohol) = 1:20, reaction temperature was 65 ℃, p H was 5.5, the reaction time was 60 min in the etherification reaction stage, the free formaldehyde content of mixed etherification melamine resin was less than 0.30%, the solid content was higher than 90%, and storage period was more than one year.(2) The curing conditions of durable coatings prepared by waterborne epoxy resin and mixed etherification melamine resin were studied, and their various properties were also deteceted. Three coatings was obtained at different conditions: for coatings 0 by dry method, The ratio of waterborne epoxy resin to mixed etherification melamine resin was 1:2, curing temperature was 220 ℃; for coatings 1 by wet method, the ratio of waterborne epoxy resin to mixed etherification melamine resin was 1:2, curing temperature was 220 ℃; for coatings 2 by wet method, the ratio of waterborne epoxy resin to mixed etherification melamine resin was 1:2, curing temperature was 230 ℃.(3) According to the national standard GB/T 13861-2009”The classification and code of danger and harmful factors in the production process”, the danger and harmful factors of GFRP bars in the production process was identificated and analysized. According to the analysis results, production facilities in the GFRP bars’ production process were classificated into different risk factors through risk evaluation method. The results were that:① In the GFRP bars’ production process, the risk rank of heat curing sizing equipment was(High risk); the risk rank of impregnator, performing mold Ⅰand frictioning plate was(Middle risk); the risk rank of creel, Ⅱ yarn guider, winding equipment, caterpillar tractor, and automatic cutting equipment was(Ⅲ Low risk).②In the glass fiber tape’ production process, the risk rank of impregnator and heat curing sizing equipment was(Middle risk);Ⅱ the risk rank of creel, yarn guider and caterpillar tractor was(Ⅲ Low risk). Based on risk assessment results above, the overall risk rank of lab factory was below average. But it still needs to improve production equipment, strengthen security measures and reduce the risk of production equipment.Besides, according to the lab factory toxic work occupational health assessment, the risk rank of lab factory was Ⅱ, which is belonging to middle risk. |
PDF Full Text Request