Synthesis Of Polymer Latex With Crosslinking Structure And Preparation Of Waterborne Damping Coatings

Waterborne damping coatings has the advantages of environmentally-friendly,no limitation of the substrate,convenient workability,etc.,which is widely used in the field of transportation,road,bridge and construction engineering.Latex polymer interpenetrating network(LIPN)design is a common way to design the polymer network in waterborne damping coatings.However,in the modern waterborne coating crosslinking systems,the micro-structure,distribution and crosslinking mechanism of various crosslinking agents have not been specifically studied to reveal the damping properties of the latex polymer and the properties of the corresponding coatings.Thus,in this dissertation by means of emulsion polymerization monomer feeding control,introducing different crosslinking agent of emulsion particles,integrated application of various characterization methods,the effect of different crosslinking systems on the crosslinking structure of latex particles,the film micro-structure and the influence of damping performance was studied.On the basis of this,optimization of pigments and additives formulation and preparation process was studied,and coatings with good comprehensive performance was obtained.The main research contents of this dissertation are as follows:1.Using different monomer feeding methods,four different types of cross-linking agents were copolymerized into latex particles at different dosage to obtain eight series of polymer latexes.Using dynamic light scattering(DLS),transmission electron microscopy(TEM),rheological and optical micro rheological method of interaction between the latex particle size and particle characterization,found that the latex particle size is mainly controlled by monomer feeding method,but different hydrophilicity and hydrophobicity of crosslinking agent,as well as distribution of crosslinking agent on the surface of latex particles has crucial influence on interaction between particles,this effect was manifested in the rheology behavior of the latex particles.Through Fourier Transform Infrared Spectroscopy(FTIR)and dynamic mechanical analysis(DMA)of different emulsion films crosslinking structures have carried on the comparative study,the results showed that all of the preparation of latex film,damping peaks are in-between 10 to 70℃,but different crosslinking led to conversion of the glass transition peaks,intensity and peak width have obvious difference,indicating the differences of LIPN microstructure.The engineering empirical parameters LA and TA value were used to evaluate the damping performance of the latex films.It was found that after the introduction of the cross-linking agent using the staged feeding method,it was easy to obtain a higher LA value,that is,a good free-layered damping performance.Among them,the DAAM/ADH cross-linking agent obtained the highest LA value at the highest amount.A higher TA value can be obtained by introducing in-situ crosslinking agent through the power feeding method,which shows better damping of the constraint layer.Among them,DVB achieves the highest TA value when the dosage is 5.0mmol.2.The above latexes was used in the preparation of waterborne damping coatings.The influence of the system composition and the preparation method on the properties of the coating was systematically studied.A pilot experiment was conducted on the polymer latex containing silane coupling agent(200kg).The particle size of the latex was about 100nm.The waterborne damping coatings prepared with silane coupling agent showed weaker damping performance and better comprehensive coating performance.The influence of packing system composition on the damping performance of water-based damping coating was studied.When mica powder and carbon black were added at 20wt%and 0.5wt%respectively,the coating showed the best damping performance.When the mill base was used in the preparation of waterborne damping coatings,the damping performance of the coating was superior to that of the direct addition of powder.The influence of the ratio of mill base to latex polymer on the coating performance was further explored.When the ratio of water-based damping coating was 4.2,the damping factor was the highest and the damping temperature domain was also the widest.The comprehensive performance of the waterborne damping coating was tested,the stability of the coating,the adaptability of the construction method,the damping performance,the surface state,the adhesion and the chemical resistance of the coating all met the technical requirements of the relevant industries.