On The Flame Retardant Performance Of Unsaturated Polyester Resin Used In VARTM Process

As a clean and renewable energy, wind energy has been paid growing attention due to intensive global energy crisis as well as increasingly prominent environment problems. Wind turbine nacelle acts as a protection device for a wind power system. Its quality is the guarantee to ensure normal operation of the entire configuration and to prolong its service life. However, there is dangerous fire hazard on the system attributed mainly to the combustible material of nacelle, blades and other parts. The issue was raised by a company asking for a suitable method to improve fire-retardant properties of the exident products, such as the turbine nacelle. The nacelle is currently made by glass fiber reinforced unsaturated polyester resin (hereinafter referred to as GFRP). The glass fiber shows thermal stability and does not burn, while unsaturated polyester resin (hereinafter referred to as UPR) is flammable. Therefore, the objective of the present study is to provide a solution towards the improvement of fire-retardant properties of UPR. In addition, the UPR must meet the processing requirement of VARTM process, which is the current manufacturing mothod.In this study, three methods of fire-retardant treatment of GFRP are investigated: (â…°) using additive type flame retardant UPR by adding a single or multiple resin flame retardants; (â…±) using chlorine, bromine or phosphorus-containing monomers in the process of condensing polyester so as to form reactive flame retardant UPR, in order to solve the proulems caused by additive type flame retardant UPR such as poor resin compatibility; (â…²) using composite flame retardant UPR by adding flame retardants into a flame-retardant UPR in order to further improve the effects of flame-retardant.Following tasks have been completed:(â…°) Determine a resin formula by adding different proportions and types of organic or inorganic flame retardants. Testing specimens of GFRP are fabricated by using the new resin formulation. Flame retardancy and mechanical properties of the specimens are evaluated; (â…±) Analyze the existing reactive flame-retardant resin UPR in terms of the flame retardancy and mechanical properties of the specimens; (â…²) Develop a new resin formula by additing liquid organic phosphorus flame retardants such as dimethyl phosphate and methyl styrene into the existing reactive flame retardant UPR. Examine the processing performance of UPR, the fire-retardant and mechanical properties of the GFRP specimens. In addition, the flame-retardant formula was optimized and experiments were conducted in terms of UPR viscosity, flame retardancy and mechanical properties of specimens. Discussion was made to explore the impacts of inorganic and organic phosphorus flame retardants on resin performances. Such mathematical analysis as visual analysis, regression analysis was used to generate the regression equations of resin viscosity, oxygen index, and tensile strength so as to figure out a suitable flame-retardant resin formula to meet the requirements of VARTM process as well as the flame-retardant and mechanical properties.This work explores the appropriate preparation methods towads the large dimensional flame-retardant composite structures in order to obtain required flame retardant properties and mechnical performances. The flame retardant GFRP products are finally made on the premise of meeting the mechanical requirements, with the oxygen index of 31.6% for UPR casting,37.0% for GFRP specimens with glass fiber volume content 48.3%. The sub-vertical burning level of the specimen is V-0 and self extinguished once away from fire.