Preparation And Study Of UV Absorption Modified Styrene-acrylic Coating With Medium Temperature Thermochromic

With the rapid development of the power grid system,equipment damage caused by overheat fault often occurs in the process of use.To speed up the monitoring speed,reduce the economic loss and protect the normal use of power equipment,the paper designs the medium temperature thermochromatic material and temperature indicator coating to have the application value in the power system.Because most of the overheating fault of the power equipment temperature rises more than 30?,generally not higher than 200?,so the color change point is designed between 70-200?.the main contents and research results are as follows:1.Study on properties of fluorosilicates styrene-acrylic emulsion modified by ultraviolet absorption.To improve the weather ability and thermal stability of styrene-acrylic polymer emulsion coatings,a series of novel kind of styrene-acrylic polymer emulsion modified with hexafluorobutyl methacrylate(HFMA),2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole(HMEB),andvinyl-trimethoxysilane(VTMS)were prepared through semi-continuous seed emulsion polymerization.The emulsions and their coatings were characterized by FT-IR,UV-Vis,XPS,DLS,TEM,Zeta potential,TG analysis,and artificially accelerated aging test.The UV stabilization mechanism was preliminarily discussed.The result of research that:(1)There are obvious UV absorption peaks at 323 nm and 350 nm.When the content of HMEB,HFMA and VTMS reaches 4%,2%and 3%,respectively,the anti-aging property of the coating is the best.(2)After 1000 h aging test,the color difference(?E)and the light loss rate(?G)of the unmodified coating are 6.86 and51.10%,respectively,while the color difference(?E)and the light loss rate(?G)of the unmodified coating are 16.05 and 72.22%,respectively.(3)By introducing fluorosilicate monomer,the thermal stability and water resistance of the coating were improved.The initial decomposition temperature was increased from 327?to 339?.(4)Using the new coating as a thermochromic material for protective coating,after 100h of ultraviolet aging,?b*is only 0.84.This new UV-resistant emulsion has excellent potential in outdoor weather-resistant protective coatings.(Chapter 2)2.Study on discoloration behavior of microencapsulated reversible thermochromic materials.The core material complex was encapsulated with urea-formaldehyde resin by in-situ polymerization.The result of research that:(1)Through the screening of discoloration behavior in different proportions,the best discoloration behavior was found when CVL:BPA:1,10-decane diol=1:2:40,the discoloration time was 21 s,the recoloration time was 13 s,and the color difference was 24.36,which was used as the core material compound.(2)The SEM and DLS characterization indicated that the microcapsules had a smooth spherical structure with a uniform particle size distribution,and the particle size distribution span ranged from 5 to 22?m.(3)Through FTIR and TG-DSC characterization,it is proved that the urea-formaldehyde resin wall material can effectively coat the core material.The color-changing temperature increases by 3?.(4)After 100 cycles,the microcapsules still showed reversible discoloration,but the color difference decreased from 23.3 to 11.1.(5)The UV accelerated aging test for 100h showed that the coating still had reversible discoloration property,and the UV absorption property of the coating greatly improved the weather resistance of the discoloration microcapsules.(Chapter 3)3.Study on cobalt-based thermochromatic materials and color-changing coatings.Two kinds of thermochromic materials(TC-A and TC-C)were successfully prepared by the liquid phase method.Among them,TC-A was prepared from an acid solution of cobalt carbonate and potassium oxalate through liquid phase steps such as oxidation of lead dioxide,catalysis of acetic acid and co-crystallization of ethanol.TC-C is prepared by a liquid reaction of diammonium hydrogen phosphate and cobalt chloride.The two kinds of materials have color change at 130?and 180?respectively,and the particle size is micron.The X-ray diffraction(XRD),TG and other test results show that:The TC-A material underwent thermal decomposition from the dark green K₃[Co(C₂O₄)₃]·3H₂O to CoC₂O₄.TC-C material is NH₄CoPO₄·H₂O,thermal decomposition,into blue CoHPO₄.The monochromic coating was prepared using TC-A and TC-C as chromic pigments,which was consistent with the material chromic condition.Using TC-A,TC-B(ammonium metavanadate)and TC-C as chromic pigments,three kinds of temperature indicator coatings were prepared by color matching.Each coating has 5-6 temperature indicator points.To improve the monitoring efficiency,a temperature measurement technology with automatic alarm and rapid monitoring was designed,and color value extraction and the color value is extracted and the color difference is calculated.(Chapter 4)...