Abstract
Studies have been carried out to investigate the effect of the chemical structure of reactive urethane acrylate prepolymers and diluents on the properties of the Uv - curable polyure-thane acrylates for secondary optical fiber coating. Several urethane acrylate prepolymers were prepared from 4,4'- dicyclohexylmethane diisocynate(HMDI) and butandiol(BD) /poly(ethylene butane adiphate diol)(SS)polyol and 2-hydroxyethyl acrylate(HEA) with dibutyl tin dilulate as a catalyst. The UV - curable secondary coating material for optical fiber was formulated from the prepolymer, photoinitiator and one of two different diluents such as tetraethyleneglycol diacrylate(TEGDA) and trimethylol propane triacrylate(TMPTA). By dynamic mechanical thermal analysis, the storage modulus of the coating material film was found to increase with increasing BD and TMPTA contents. The maximum tan 8 peak for the coating materials prepared in this study was in the range of 70 and 90˚C. The maximum tan 8 and loss modulus peaks shifted to higher temperature with increasing BD content. The tensile strength and modulus increased with the increase of the number of functional group of diluent. The higher strength and modulus are due to the high content of hard segment and crosshnking by multifunctional diluent, respecti-vely. The desirable BD content is in the range of 5Omol% % and 6Omol %, and TMPTA content is about 30wt % for secondary coating material of high modulus.
