间苯二胺扩链的芳香族聚氨酯弹性体的合成与性能

以甲苯二异氰酸酯和聚氧化丙烯二元醇合成聚氨酯预聚体,通过间苯二胺扩链,得到一种芳香族聚氨酯弹性体。探讨了异氰酸根指数(R值)对聚氨酯预聚体和弹性体合成及固化行为的影响;并利用FT-IR、DSC和拉伸实验等对合成聚氨酯的结构、组成、热性能和力学性能等进行了表征。结果表明,随着R值的增加,聚氨酯弹性体的凝胶时间和表干时间逐渐缩短,拉伸强度增大,断裂伸长率降低,硬段的玻璃化转变温度和热分解温度升高;R值为2.0、2.5和3.0时,合成了固化参数适宜、拉伸性能优异、可用于混凝土防护的聚氨酯弹性体材料。

Synthesis and Performance of Aromatic Polyurethane Elastomer with m-Phenylenediamine Chain Extender

Polyurethane prepolymer was synthesized with toluene diisocyanate and polypropylene glycol, and then a high performance aromatic polyurethane elastomer was prepared by extending the chains of polyurethane prepolymer with m-phenylenediamine. The effect of R value （isocyanate index） on synthesis and curing behavior of polyurethane prepolymer and elastomer was investigated. Additionally, the structure, composition, thermal property and the tensile property of the polyurethane were characterized by FT-IR, DSC and tensile test. Results showed that the gel time and tack-free time of the polyurethane elastomer gradually were shorten and the elongation at break de- creased, while the tensile strength, glass transition temperature and thermal decomposition temperature increased with R value increasing. Consequently, polyurethane elastomer with the good curing behavior and tensile property was prepared when R was 2.0, 2.5 and 3.0, which could be used to protect the concrete.