本征柔性环氧树脂的制备及其增韧中温固化预浸料的研究
发布时间：2019-05-24 17:26
【摘要】：预浸料是由树脂浸润连续纤维或织物得到的组合物,通常树脂体系呈B阶段,是复合材料的中间体。环氧树脂作为最常用的中温固化预浸料树脂基体,必须具有良好的断裂韧性从而使预浸料中的纤维能有效传递应力,同时需要通过控制基体树脂的粘度来调整预浸料的粘接性能,并降低预浸料的树脂流动度以满足复合材料成型工艺要求。本论文采用聚氨酯预聚体接枝改性制备本征柔性环氧树脂(Intrinsic Flexible Epoxy Resin,简称IFEP),应用于预浸料树脂体系和中温固化碳纤维预浸料中,以实现增韧效果和复合材料成型工艺适应性的统一。1.以二苯基甲烷二异氰酸酯(MDI)与聚氧化丙烯二醇(PPG, Mn=1000,2000,3000)通过预聚反应制备端异氰酸酯基聚氨酯预聚体(PPU1000, PPU2000, PPU3000),进而与双酚A型环氧树脂的羟基发生接枝反应得到不同分子量的本征柔性环氧树脂IFEP (IFEP1000, IFEP2000,IFEP3000)。异氰酸根基团含量测试表明预聚反应4h可达理论值,红外光谱和核磁共振波谱可确认PPU和IFEP的结构,凝胶渗透色谱(GPC)测试表明PPU及IFEP分子量与理论值一致。2.利用三种本征柔性环氧树脂(IFEP1000, IFEP2000, IFEP3000)制备了三种增韧树脂体系,考察了三种树脂体系的粘弹性、固化动力学、冲击韧性、热性能和增韧机理。流变测试表明随着PPG分子量的增加,IFEP增韧环氧树脂体系的特征松弛时间延长,凝胶时间缩短。相对于纯环氧树脂体系,IFEP增韧环氧树脂体系韧性大幅提升,其中,IFEP2000增韧环氧树脂体系KIC和冲击强度达到最佳。由于聚氨酯组分和环氧树脂溶解度参数的不同导致聚氨酯在环氧树脂基体中发生微相分离,IFEP2000增韧体系具有适中的相畴尺寸及分布,综上,以IFEP2000增韧环氧树脂体系综合性能最佳。3.应用IFEP2000本征柔性环氧树脂制备了不同IFEP含量的增韧树脂体系,考察了不同树脂体系的力学性能、固化特性、热性能和微观形貌等。力学测试表明随着IFEP含量增加,IFEP增韧体系冲击强度提高,60 wt%IFEP增韧环氧树脂体系效果最佳。DSC测试表明IFEP增韧树脂体系固化反应放热减少,DMA结果显示随着IFEP含量增加,IFEP增韧树脂体系Tg先下降后上升,60 wt%IFEP增韧环氧树脂体系Tg可达166℃。SEM测试表明随着IFEP含量增加,聚氨酯微相分离程度增大,60wt%IFEP增韧环氧树脂体系微相分离相畴为0.148～0.497μ m。4.应用60wt%IFEP2000制备环氧树脂体系,以热熔两步法工艺制备了T300碳纤维预浸料,考察了预浸料的粘温曲线、树脂流动度,并评价了复合材料板材的力学性能和微观形貌。结果表明相对于末增韧环氧树脂基预浸料,IFEP增韧预浸料具有更宽的加工窗口,树脂流动度降低,层间断裂韧性、层间剪切强度、冲击后压缩强度(CAI)提高,SEM结果显示IFEP增韧树脂基体与碳纤维结合紧密,聚氨酯在树脂基体中发生微相分离。
[Abstract]:Prepreg is a composition made of resin infiltrated continuous fiber or fabric. Usually, the resin system is in stage B and is the intermediate of composite material. Epoxy resin, as the most commonly used medium temperature curing prepreg resin matrix, must have good fracture toughness so that the fibers in the prepreg can effectively transfer stress. At the same time, it is necessary to adjust the adhesive properties of the prepreg by controlling the viscosity of the matrix resin, and reduce the resin mobility of the prepreg to meet the requirements of the composite molding process. In this paper, the intrinsic flexible epoxy resin (Intrinsic Flexible Epoxy Resin, was prepared by polyurethane prepolymer grafting modification. IFEP), was used in prepreg resin system and medium temperature curing carbon fiber prepreg. In order to realize the unity of toughness effect and the adaptability of composite molding process. Isocyanate terminated polyurethane prepolymer (PPU1000, PPU2000, PPU3000) was prepared by prepolymerization of diphenylmethane diisocyanate (MDI) with polypropylene oxide diol (PPG, Mn=1000,2000,3000). Then the intrinsic flexible epoxy resin IFEP (IFEP1000, IFEP2000,IFEP3000) with different molecular weight was obtained by grafting with hydroxyl groups of bisphenol A epoxy resin. The content test of isocyanate group showed that the theoretical value could be reached by prepolymerization for 4 h, the structure of PPU and IFEP could be confirmed by IR and NMR spectra, and the molecular weight of PPU and IFEP was consistent with the theoretical value. 2. Three kinds of toughened resin systems were prepared by using three kinds of intrinsic flexible epoxy resin (IFEP1000, IFEP2000, IFEP3000). The viscosity, curing kinetics, impact toughness, thermal properties and toughness mechanism of the three resin systems were investigated. The results showed that the characteristic relaxation time and gel time of IFEP toughened epoxy resin system were prolonged and the gel time was shortened with the increase of molecular weight of PPG. Compared with pure epoxy resin system, the toughness of IFEP toughened epoxy resin system is greatly improved, among which IFEP2000 toughened epoxy resin system KIC and impact strength are the best. Due to the different solubility parameters of polyurethane and epoxy resin, polyurethane is separated in epoxy resin matrix. IFEP2000 toughened system has moderate phase domain size and distribution. The comprehensive properties of epoxy resin system toughened by IFEP2000 are the best. Toughened resin systems with different IFEP content were prepared by IFEP2000 intrinsic flexible epoxy resin. The mechanical properties, curing properties, thermal properties and micromorphology of different resin systems were investigated. The mechanical test showed that the impact strength of IFEP toughened system increased with the increase of IFEP content, and the effect of 60 wt%IFEP toughened epoxy resin system was the best. DSC test showed that the curing reaction heat release of IFEP toughened resin system decreased, and DMA results showed that with the increase of IFEP content, The Tg of IFEP toughened resin system decreased at first and then increased, and the Tg of 60 wt%IFEP toughened epoxy resin system reached 166 鈩，
本文编号：2485043
[Abstract]:Prepreg is a composition made of resin infiltrated continuous fiber or fabric. Usually, the resin system is in stage B and is the intermediate of composite material. Epoxy resin, as the most commonly used medium temperature curing prepreg resin matrix, must have good fracture toughness so that the fibers in the prepreg can effectively transfer stress. At the same time, it is necessary to adjust the adhesive properties of the prepreg by controlling the viscosity of the matrix resin, and reduce the resin mobility of the prepreg to meet the requirements of the composite molding process. In this paper, the intrinsic flexible epoxy resin (Intrinsic Flexible Epoxy Resin, was prepared by polyurethane prepolymer grafting modification. IFEP), was used in prepreg resin system and medium temperature curing carbon fiber prepreg. In order to realize the unity of toughness effect and the adaptability of composite molding process. Isocyanate terminated polyurethane prepolymer (PPU1000, PPU2000, PPU3000) was prepared by prepolymerization of diphenylmethane diisocyanate (MDI) with polypropylene oxide diol (PPG, Mn=1000,2000,3000). Then the intrinsic flexible epoxy resin IFEP (IFEP1000, IFEP2000,IFEP3000) with different molecular weight was obtained by grafting with hydroxyl groups of bisphenol A epoxy resin. The content test of isocyanate group showed that the theoretical value could be reached by prepolymerization for 4 h, the structure of PPU and IFEP could be confirmed by IR and NMR spectra, and the molecular weight of PPU and IFEP was consistent with the theoretical value. 2. Three kinds of toughened resin systems were prepared by using three kinds of intrinsic flexible epoxy resin (IFEP1000, IFEP2000, IFEP3000). The viscosity, curing kinetics, impact toughness, thermal properties and toughness mechanism of the three resin systems were investigated. The results showed that the characteristic relaxation time and gel time of IFEP toughened epoxy resin system were prolonged and the gel time was shortened with the increase of molecular weight of PPG. Compared with pure epoxy resin system, the toughness of IFEP toughened epoxy resin system is greatly improved, among which IFEP2000 toughened epoxy resin system KIC and impact strength are the best. Due to the different solubility parameters of polyurethane and epoxy resin, polyurethane is separated in epoxy resin matrix. IFEP2000 toughened system has moderate phase domain size and distribution. The comprehensive properties of epoxy resin system toughened by IFEP2000 are the best. Toughened resin systems with different IFEP content were prepared by IFEP2000 intrinsic flexible epoxy resin. The mechanical properties, curing properties, thermal properties and micromorphology of different resin systems were investigated. The mechanical test showed that the impact strength of IFEP toughened system increased with the increase of IFEP content, and the effect of 60 wt%IFEP toughened epoxy resin system was the best. DSC test showed that the curing reaction heat release of IFEP toughened resin system decreased, and DMA results showed that with the increase of IFEP content, The Tg of IFEP toughened resin system decreased at first and then increased, and the Tg of 60 wt%IFEP toughened epoxy resin system reached 166 鈩，
本文编号：2485043
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