Preparation Of Functional Copolymer Emulsion And Its Application In Humidity Controlling Coatings

With the development of science and technology and improvement of people’sliving standard, people’s requirements become more and higher for comfort, securityof living conditions. Indoor hot and wet environment as a key factors of influencingthe comfort of living conditions have been attention. Although the effect is obvious, itneeds to consume energy, higher cost and human maintenance and management bythe active method to regulate the indoor relative humidity, namely air conditioningtechnology. In consideration of the sustainable development strategy, it was not longmethod, and only as auxiliary methods to regulate indoor hot and wet environment. Itis a kind of ecological humidity method, no artificial energy by the passive method,namely using of renewable energy or material with dehumidifying and humidityincreasing characteristics. The humidity controlling coatings is a kind of functionalcoatings with dehumidifying and humidity increasing characteristics. Compared totraditional humidity controlling materials, its biggest advantage is that it could useinterior space effectively, and do not take up interior space. Therefore, the humiditycontrolling coatings has broad prospects of market. Our research group broke throughthe traditional view of truth, which regards truth as poor water resistance due to betterwater absorption of coatings, successfully prepared the water-sensitive breathablecoatings under the important precondition that ensure the basic performance ofcoatings. The basic properties of the coatings based on the modified acrylatecopolymer are all up to the national standard of interior wall, and showed goodhumidifying performance in little box sealing environmentBased on our research group study of amphiphilic acrylate copolymer and thehumidity controlling coatings, according to the mature preparation technology of thehumidity controlling coatings, batch humidity controlling coatings were prepared forindoor painting and the performance of humidifying was also examined. The goal isto prepare the coating that can adjust indoor moisture automatically and has goodperformance. Therefore, the functional monomers were added in the preparationmodified acrylate polymer emulsion. The interior wall coatings were also preparedwith acrylate polymer emulsion as film-forming materials, inorganic porousmulti-layer material as pigments and fillers. The paper is divided into the followingparts:Firstly, the current research of the humidifying materials and humiditycontrolling coatings is reviewed by two parts. It was illuminated that the type,performance, merits and demerits of humidifying material; several views aboutevaluation of the humidifying material performance index; testing standards andtypical methods of humidifying materials; and the type, merits and demerits of humidity controlling coatings.Secondly, the outdoor humidity variation in the year2011was found based theanalysis of regularity of the humidity, temperature of Lanzhou city that is the typicalrepresentative of the northern region. The next, a batch soap-free amphiphilic acrylatecore-shell copolymer emulsion was prepared by pre-mature synthesis technology ofour group. The water-sensitive breathable coatings were prepared by mixing theabove emulsion as film-forming material combined with porous filler(montmorillonite, diatomite, etc.), and pigments (such as titanium dioxide). Based onhumidifying effect of the pilot test results, the actual use of the humidity controllingeffect was investigated by brushing the common interior wall with humiditycontrolling coatings. The result showed that the coatings had the function of slowingindoor humidity reduction.Thirdly, the epoxy-acrylate copolymer emulsion was successfully prepared withthe ionic/ion compound emulsifier and glycidyl methacrylate (GMA) as modifiedmonomers by using epoxy modified acrylic ester approaches. The structure, thermalstability and particle morphology of copolymers were characterized by usingflourier-infrared spectrometry (FT-IR), thermogravimetric analysis (TG) andtransmission electron microscope (TEM), respectively. Finally, the best syntheticprocess of epoxy-acrylate copolymer emulsion was obtained. The functional coatingswith humidifying performance were prepared by mixing the epoxy-acrylatecopolymer emulsion as film-forming material with porous fillers and pigments. Thebasic performance of coatings was tested, and water absorption of film-formingmaterial and coatings were also investigated. The results showed that the basicproperties of the coatings based on the modified acrylate copolymer are all up to thenational standard of interior wall, and had good humidifying performance.Fourthly, in order to further improve hydrophilic and water absorption of acrylatecopolymers, epoxy-acrylate copolymers emulsion with high water absorption wereprepared by introducing hydroxyethyl methacrylate (HEMA). Some exploringparameters such as reaction temperature, content of experiment initiator, functionmonomers and emulsifiers were investigated. The structure, thermal stability andparticle morphology of copolymers were characterized by using flourier-infraredspectrometry (FT-IR), thermogravimetric analysis (TG) and transmission electronmicroscope (TEM), respectively. The best synthetic copolymer emulsion process wasultimately obtained. The humidity controlling coatings with humidifying performancewere obtained by mixing the epoxy-acrylate copolymer emulsion as film-formingmaterial with porous fillers and pigments. These parameters, which contained thereaction temperature and content of functional monomers on the effect of polymerperformance, were discussed. The results showed that the basic properties of the coatings based on the above acrylate copolymer are all up to the national standard ofinterior wall, and had good humidifying performance.Fifthly, the best synthetic copolymer emulsion process was ultimately obtainedwith soap-free emulsion polymerization technology, through exploring parameters ofexperiment initiator, reaction temperature, and content of function monomers. Thecopolymer structure, thermal stability, the particle shape and size distribution of theobtained soap-free epoxy-acrylate copolymer emulsion were characterized by TG,dynamic scattering (DLS) and TEM, respectively. The humidity controlling coatingswith humidifying performance were obtained by mixing the above copolymeremulsion as film-forming material with porous fillers and pigments. The resultsshowed that the basic properties of the coatings based on the above acrylatecopolymer are all up to the national standard of interior wall, and had goodhumidifying performance.In short, it was proved that the obtained humidity controlling coatings possessedslowing indoor humidity violent occurrence and increasing indoor humidity throughtesting the actual indoor humidifying ability. The prepared three epoxy-acrylatecopolymer emulsions possess outstanding water absorption capacity, water resistance,the dehumidifying and humidity increasing properties. Moreover, the obtainedhumidity controlling coatings have the characteristics of environmental protection andenergy-saving, and are expected to apply in painting of the building interior wall.