Synthetic Reaction of Castor Oil-Urethane Acrylate Oligomers for Optical Fibers

It was found that the reaction of 2,4-toluene diisocyanatc (2,4-TDI) and hydroxyethy acrylate (HEA) forming ITP is a second reaction, and so is the reaction of ITP with castor oil (CAS) forming VTPU, From the rate constant (k_p) and apparent activity energy (E_a) of the reactions, the product VTPU with regular structure can be modulated by using the difference of reactivity between the pare- and orth- NCO in 2,4-TDI at different temperature with two-step reactions. The solvent-free paint consisting of VTPU, acrylic diluents and photoinitiator cured by ultraviolet radiation was satified for optical fibers fabrication.