Two series of thermotropic liquid crystalline polyureas were synthesized by the copolymerization of benzidine (or o-tolidine),1,6-hexane diamine and 2,4-toluene diisocyanate.

为合新型热致液，以含液基元的联二（或联邻）、1，6-己二、2，4-二异氰酸酯为原料进行合。

Toluene diisocyanate (TDI) is one of the most useful kinds of isocyanateth that is produced by the method of phosgenation of amine.

二异氰酸酯(TDI)是异氰酸酯化合物中应用最广泛的品种之一,其工业生产主要采用光化法。