3238树脂及其改性

 采用芳香二胺对3238韧性中温固化环氧树脂体系进行了改性。通过芳香二胺和环氧树脂预先反应，消除了芳香二胺对中温环氧树脂的固化及工艺的影响，改性前后差示扫描量热法（DSC）初始温度和峰顶温度的差别仅有3 ℃，最终固化程度的差别也仅有1%。通过芳香二胺刚性结构的引入，由于芳香二胺和环氧树脂的交联密度高于双氰胺环氧树脂体系，因此引入芳香二胺刚性结构提高了3238树脂的耐热性，干态玻璃化转变温度提高了29 ℃，且纯固化后树脂吸湿量降低了0~34%，湿态玻璃化转变温度提高了46 ℃。改性后树脂可能形成了高低交联密度区，产生了固化物交联状态的不均匀，在提高树脂体系耐热性能的同时，保持其原有的韧性，树脂浇注体的拉伸应力应变曲线呈明显的塑性变形，拉伸断裂伸长率达5~31%，复合材料的断裂韧性达1 133 J/m²。

Resin 3238 and Its Modification

This paper introduces a modification technology of 3238 medium temperature curing epoxy resin with aromatic diamine. The infection to epoxy resin curing cycle and forming process is avoided by the pre reaction of aromatic diamine and epoxy resin bisphenol A. The difference of the differential scanning calorimetry(DSC) onset (Ti) and top (Tp) temperature is only 3℃. The difference of the final curing degree is 1%. The hygrothermal properties of resin 3238 are improved because of the introduction of the rigidity structure of aromatic diamine and its higher crosslinking density than that of dicyandiamide and epoxy resin.The moisture absorption of the resin is decreased by 0.34%,and the dry and wet glass transition temperature is increased by 29℃ and 46℃ respectively.Toughness is retained because of the forming of a high and low crosslinking density section.The tensile stress-strain curve exhibites clear plastic deformation and its elongation reaches 5.31%.The model II fracture toughness of the composite reaches 1 133 J/m².