| In the field of thermosetting plastics applications,the most commonly used resin matrix has three kinds,namely epoxy resin(EP),unsaturated polyester resin(UP),phenol-formadehyde resin(PF),and the UP resin shared 75% of the total market.Compared with the phenolic resin,although the cost of UP is close to PF,but the mechanical properties better,not need high pressure and no water product.UP resin has slightly below mechanical properties which compared with EP but more cheeper than that.So UP is widely applicable to all industrial areas.With the continuous development of technology,In the traditional general model based on the modified UP has been widely used in the field of construction,new energy field,aerospace field.Although some research institutes and enterprises have modified UP to achieve the high-intensity,high temperature environment and other special conditions of the application,but the price of modified UP is more expensive,which can not be largescale application in the civilian areas.While the UP of current market can not well applied in manufacturing the nacelle and fairing of wind power generation.Usually UP have great brittleness,the fiberglass that made of current grade UP have low toughness.The one-time molding yield of long fiber is lower than short fiber.The rate of defective products in molding is higher than hand molding and winding forming.The rate of defective products in molding hand lay-up and filament winding.The surface quality of molded products is also lower than that of thermoplastic resin injection molding products.It is because of UP resin's viscosity,solidification exothermic,and shrinkage ratio.In order to improve the performance and yield of large glass fiber reinforced plastic products,the purpose of this paper is to Synthesis one kind of UP resin which has lower viscosity,lower solidification exothermic,and lower shrinkage ratio through the fusion method.Neopentyl glycol,diethylene glycol will replace of conventional diatomic alcohol,Resin costs will not increase.In the synthesis process,the proportion of the unsaturated double bonds in the resin is appropriately reduced(the molar percentage of the total amount of the unsaturated acid anhydride to the total number of anhydrides is about 50% to 60%),and choose the right additives to reduce the solidification exothermic,and shrinkage ratio of resin.The resin can be used in Manufacturing 1MW~3MW wind turbine nacelle fairing which use 1 m3 volume of resign through Resin Transfer Molding(RTM).As the research shows,the apparent quality and dimensional stability of glass fiber reinforced plastic products are mainly affected by the exothermic peak and curing shrinkage during resin curing.To ensure the strength of the resin itself,reduce the proportion of unsaturated double bonds in the resin,which is good to reduce the exothermic peak of resin curing.Reduce the degree of cross-linking of resin curing can enhance toughness of resin.Reducing the viscosity of the resin which can help to improve the curing efficiency of the resin and reduce the residue of small molecules.It is good to improve the resin and fiber impregnation performance and reduce the proportion of dry fiber.The correct appropriate retarder can control the resin curing reaction rate,and effectively reduce the resin exothermic peak.In addition select the appropriate Low profile additives(LPA)and low exothermic additive,to reduce the exothermic peaks during the curing process can reduce resin shrinkage ratio.Adjust the resin curing shrinkage... |
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