液晶环氧增韧环氧树脂基体的研究

【作者】 常鹏善；

【导师】 王汝敏；

【作者基本信息】 西北工业大学 ， 材料学， 2001， 硕士

【摘要】 本文提出用液晶环氧原位复合增强增韧的思路，以提高环氧树脂的韧性。 以对羟基苯甲酸和对苯二酚为原料，用浓硫酸—硼酸共沸催化法合成对羟基苯甲酸对苯二酚酯；再由对羟基苯甲酸对苯二酚酯与环氧氯丙烷进行反应合成酚酯型液晶环氧——4、4’—二缩水甘油醚基二苯基酰氧（PHBHQ）。用差示扫描量热（DSC）、热台偏光显微镜（POM）、傅立叶变换红外光谱（FTIR）等方法研究了PHBHQ的相行为、PHBHQ与4、4’—二氨基二苯甲烷（DDM）和混合芳香胺4#[DDM:DDS（4、4’—二氨基二苯砜）:DDE（4、4’—二氨基二苯醚）=5:2:1质量比)两种固化剂反应的固化特性。结果表明：PHBHQ为一单变相液晶，只在降温过程中于131—94℃呈现向列相液晶态，在固化过程中，PHBHQ能形成取向有序的介晶域；PHBHQ/DDM体系的固化反应按自催化反应机理进行，固化过程中产生的羟基可进一步加速反应，其分步反应的动力学参数分别为Ea₁=66.51KJ/mol，lnA₁=6.65，Ea₂=69.05KJ/mol，lnA₂=7.34。 研究了PHBHQ对环氧树脂的增韧作用。结果表明：采用与介晶相温度相匹配的固化剂DDM或混合芳香胺4#，制定合理的固化工艺，加入PHBHQ可使E-51树脂的韧性得到明显改善。当PHBHQ用量为50％时，PHBHQ/E-51树脂/混合胺4#固化物的冲击强度和玻璃化温度分别为40.2KJ/m²、182.9℃。运用扫描电子显微镜（SEM）、广角X射线衍射（WAXD）和动态力学性能分析（DMTA）研究了改性树脂的相态结构与增韧机理，PHBHQ与E-51树脂为部分相容体系，在成型过程中体系发生相分离，形成取向有序的PHBHQ介晶域，介晶域起到引发、分支、终止裂纹的作用，从而使增韧树脂的冲击韧性得到改善。更多还原

【Abstract】 In our present work, we took a new in-situ toughening method by using liquid crystalline epoxy to improve the toughness of epoxy resin.A novel liquid crystalline epoxy resin 4-epoxypropoxy phenyl-4?epoxypropxy benzoate (PHBHQ) was synthesized. The phase behaviours, curing character of PHBHQ reacted with 4,4?diaminodiphenylmethane(DDM) or mixed aromatic diamine [DDMIDDS(4,4?diaminodiphenylsulfone)/DDE(4,4?diaminodiphenyl ester)=512/ 1 wt ratio] were characterized by Differential Scanning Calorimetry (DSC) and Polarized Optical Microscopy(POM). The results indicated that PHBHQ showed nematic phase duiing cooling process between 1310C and 940C.The curing mechanism and kinetics of PHBHQ reacted with DDM were studied by Flourier Transmit Infrared (FTIR). The curing reaction proceeded in auto-accelerating mechanism and was accelerated by the hydroxyl group produced in the curing process. The kinetics parameters of each step of curing reaction were calculated: Ea1=:66.5 1KJ/mol, lnA1=6.65, Ea2= 69.O5KJ/mol, lnA2?.34.PHBHQ was used to toughen bisphenol-A diglycidyl (E-5 1 resin). Mechanical characterization and thermal property were greatly increased by using curing agent of mixed aromatic diamine , the impact strength and glass transition temperature of E-5 1 resin modified by 5Owt% PHBHQ were 40.2KJIm2 and I 82.90C respectively. Studies using Scanning Electronic Microscopy (SEM), Wide-angle X-Ray Diffraction(WAXD) and Dynamic Thermomechanical Analysis(DMTA) showed the formation of two-phase structure with oriental ordered mesogenic domain which can initiate, branch, terminate the crack dispersed in the continuous epoxy matrix.更多还原