Study On Preparation And Property Of Glass Fiber Reinforced Unsaturated Polyester Composites With Vartm Process

Glass fiber reinforced unsaturated polyester composites have the advantages ofhigh specific strength and specific modulus,low cost,etc. The application hascontinued development in the past30years. Vacuum Assisted Resin TransferMolding (referred to as VARTM), one of the Liquid Composite Molding (LCM)techniques, is cost effective and suitable for large and complex structures such asstructures with insert, ribs and core. Vacuum pressure not only provides the maindriving force for performs impregnation, but also draws out the entire air andmoisture. Therefore, the VARTM process can produce composite with high quality.Preparation of glass fiber reinforced unsaturated polyester composites withVARTM process has been studied systematically. Effect of processing parameters onresin flow behavior and mechanical properties also has been investigated in this paper.The purpose is to provide theoretical foundation for shortening the molding cycle andimproving product quality. The main contents and results are summarized as follows.Firstly， the experimental platform of VARTM process has been designed andbuilt. The raw materials, equipments and the manufacturing process have beendescribed in detail, including tool preparation, fabric layup, cavity sealing anddemolding. The cavity sealing is critical to affect the resin flow behavior andcomposites quality.Secondly, the gel experiment of the TH110-350R vinyl resin has been carriedout. Its dynamic viscosity characteristics, isothermal viscosity characteristics and theeffect of temperature on gel characteristics have been analyzed, laying a foundationfor the VARTM process. In addition, test methods on the impregnation propertiessuch as density, fiber volume fraction and voids content have been summarized.According to mechanical properties test standards, sample preparation, testingprocess and calculation method on tensile, bending and impact properties have beenintroduced respectively as well.Finally, the samples have been fabricated by the VARTM process with differentparameters such as size of infusion media, compaction time, vacuum pressure, fiber stacking thickness and fiber types. The impregnation properties, such as fiber volumefraction and voids content, and the mechanical properties, such as tensile, bendingand impact properties have been tested and calculated. Effect of processingparameters on the properties of composites by VARTM has been studied, which canobtain the optimum technique parameters. When the size of infusion media is250mm×270mm, the compaction time is15min and the vacuum pressure is-98kPa,composites with satisfactory quality can been obtainied by VARTM, and the moldingcycle is reasonable. Samples with unidirectional fabric have maximum mechanicalproperties while samples with biaxial (±45°) fabric show the poorest mechanicalproperties, and samples with biaxial (0°/90°) fabric have relatively satisfactorycomprehensive mechanical properties. In order to meet the engineering requirement,fiber weave way and rational ply should be designed to obtain the composites withthe specific requirement.