选用聚醚二元醇(PPG)和甲苯二异氰酸酯(TDI)为原料,合成聚醚型聚氨酯预聚体.采用该聚氨酯预聚体(PUP)、扩链剂、交联剂对TDE-85/甲基四氢邻苯二甲酸酐(MeTHPA)环氧树脂进行改性,通过扫描电镜与红外光谱分析,探讨聚氨酯(PU)改性环氧树脂(EP)体系的结构特征.结果表明:TDE-85与MeTHPA之间发生固化反应,形成环氧聚合物网络Ⅰ;1,4-丁二醇(1,4-BDO)及三羟甲基丙烷(TMP)与PU预聚体之间发生了扩链、交联反应,形成聚氨酯聚合物Ⅱ;PU改性TDE-85/MeTHPA树脂为非均相结构,PU含量是影响PU/EP材料两相相容性和相区尺寸的主要因素;当添加的PUP质量分数为15%时,PU改性TDE-85/MeTHPA体系具有互穿聚合物网络结构特征.
PU-modified TDE-85/MeTHPA epoxy resin was prepared with chain-extended reagent (1,4-BDO), crosslink agent (TMP), and polyurethane prepolymer (formulated by polypropylene glycol (PPG) and 2,4-toluene diisocyanate (TDI). The structure characters of this system were discussed by SEM and IR. The results indicate that polymer network Ⅰ was obtained by the curing reaction between TDE-85 and MeTHPA, and polymer network Ⅱ was obtained by chain-extended and cross linking reaction of 1,4-BDO, TMP and polyurethane prepolymer (PUP). Meanwhile the PU-modified TDE-85/MeTHPA resins have heterogeneous structure. The content of PU plays a main role in the compatibility and size of phases of modified materials. An optimum mass fraction of PUP (15%) is determined that shows obvious characters of interpenetrating polymers network (IPN) structure.