The Parathion And Properties Study Of UV-curing Fluorinated Polyurethane Elastic Coatings

A kind of UV curing polyurethane resin terminated with double bond was prepared using hydroxyl terminated polybutadiene （HTPB） as soft segment,1,4-butanediol （BDO） isophorone diisocyanate （IPDI） as hard segment, and 2-hydroxyethyl acrylate （HEA） as the blocking agent. The structure of product has been proved by fourier transform infrared spectrum （FTIR） and proton nuclear magnetic resonance （1HNMR）.Various formulated UV-curable polyurethane coatings were prepared by blending ene-terminated polyurethane, fluoroacrylate monomer, multifunctional thiol crosslinker and photoinitiator 184 upon UV exposure. The influence of the content of Pentaerythritol tetra （3-mercaptopropionate） （PETMP）, photoinitiator and coating thickness on the photocuring behavior of the polyurethane coatings was monitored via RT-IR spectroscopy. The results showed that the final degree of double bond conversion （DC） and the rate of polymerization （Rp） were observed the same increasing tendency with with increasing the content of PETMP and photoinitiator 184, and the DC and Rp were achieved the maximum value when the coating thickness was 30 μm. The change of the contact angle and interface energy, gel yield, pencil hardness, adhesion, water absorption and glossiness were studied with increasing the content of fluoroacrylate monomer and multifunctional thiols, which made the improvement of overall performance of the coatings. The mechanical strength and recovery performance tested using universal tensile testing machine showed excellent elastic property. Through the comprehensive evaluation of the performance of coatings, the optimum formula was HTPU 100,3wt% PETMP,2wt% fluoroacrylate monomer and 2wt% photoinitiator 184.A series of UV-curable fluorinated polyurethane coatings was also synthesized using hydroxyl terminated polybutadiene （HTPB）, dihydric fluoroalcohol （F（OH）₂）,1, 4-butanediol （BDO）,2-hydroxyethyl acrylate （HEA） and isophorone diisocyanate （IPDI） as starting agents in this work. The successful introduction of fluorine was proved by FTIR and 19F-NMR testing. The gel permeation chromatography （GPC） results showed that the molecular weight decreased and the molecular weigth distribution became wider when increasing the content of dihydric fluoroalcohol. The thermal gravimetric analysis （TGA） results indicated that the thermostability was improved by increasing the content of dihydric fluoroalcohol. The coatings showed good hydrophobic property when the dihydric fluoroalcohol content was up to 16wt%（mole percent）, and the contact angle tested by optical contact angle measuring instrument（OCA） reached 104.3°. The rheological behavior testing results showed a lower viscosity and better rheological properties with increasing the dihydric fluoroalcohol content.