Unsaturated polyester technology is becoming more and more mature with the development of production. So far, it has gradually formed its own unique set of production, application theory and technical system.
(1) Theoretical aspects The theoretical progress of unsaturated polyester plays an important role in promoting the improvement of production technology.
① The understanding of the polycondensation reaction mechanism in the synthesis process of unsaturated polyester is of great significance for rationally determining the staged reaction process and obtaining high-quality products with uniform molecular linkage structure. On this basis, different types of resin products such as m-benzene type, bisphenol A type, neopentyl glycol type, etc. were produced, with a wide variety and improved performance.
② For the analysis, derivation and calculation of the average molecular weight and molecular weight distribution of polyester, it provides a statement to predict and control the molecular weight of the polyester polycondensation product.
③ The understanding of the gelation and curing mechanism of polyester is the basis for the successful determination of various FRP molding process conditions. For all mechanized, semi-mechanized and even manual molding methods, the determination of the process conditions must meet the requirements of specific resins and gels and curing conditions. Conversely, different molding methods also place specific requirements on the gel and curing properties of the resin.
④ The research results on the thickening mechanism of sheet molding compound (SMC) and the mechanism of low shrinkage and low profile additives have overcome the technical difficulties in the production of SMC, making polyester molding compounds into large-scale, high-efficiency and low-cost The new stage of producing high-quality products further promotes bulk molding compound (BMC), thick molding compound (TMC), high strength molding compound (HMC), oriented fiber molding compound (ZMC), and high strength sheet molding compound (XMC) ) The development of isoplastic materials.
⑤ The research on the structural theory of composite materials reveals the special mechanical properties of this anisotropic material, which results in the structural design and calculation theory of composite materials, which provides important guidance for practical production and application.
⑥ The study of the interface state of glass fiber and resin is of great significance to improve the various physical and chemical properties of the laminate. According to this, the use of various coupling agents has been produced, which has significantly improved the performance of composite materials.