Synthesis Of Waterborne Acrylate Emulsion And Its Coatings Study On Preparation And Damping Properties

Waterborne damping coatings are widely used in rail transit,automobile industry and exterior walls of buildings due to their characteristics of low VOC,simple construction and high coating efficiency,waterborne acrylate can be used as the basic emulsion of damping coatings.It has excellent damping performance and avoids the harm of organic solvents to the environment.It is a kind of green material,and can be designed according to the specific working environment of coatings.1.A series of dimer copolymers were synthesized by random copolymerization using butyl acrylate(BA)and isooctyl acrylate(2-EHA)as soft segment monomers and styrene(St)and methyl methacrylate(MMA)as hard monomers.The effects on the emulsion properties,hydrophobic properties of the adhesive film,mechanical properties and damping properties were investigated by varying the types of soft and hard monomers as well as their ratios.the results showed that the hydrophobic and mechanical properties were greatly improved with more hard monomer ratio,and the copolymer product still has good damping performance at low temperature around-40℃,and the emulsion formulation when the effective damping temperature range of the binary random copolymer reaches the widest value of 70℃.2.In order to study the effect of particle structure on damping properties,a core-shell acrylate emulsion was synthesized,with MMA and ST copolymer as the core and BA homopolymer as the shell,by changing the amount of crosslinking agent,it is found that the hydrophobicity and mechanical properties are directly proportional to it,and the water contact Angle can reach 96.5~°with the increase of the amount of crosslinking agent.,the maximum tensile fracture strength is 1.21 MPa,but the improvement of effective damping temperature domain is not obvious,therefore,in order to broaden the damping temperature domain,a series of emulsions with multi-layer core-shell type were prepared using BA,MMA and ST as comonomers and HEMA as functional monomers by using Fox equation,the results showed that when the amount of hydroxyethyl methacrylate(HEMA)was 2%,the widest effective damping temperature domain was 135.60℃,but there would be a trough between the two damping peaks,therefore,in order to improve compatibility,the span of T_gbetween layers was narrowed to achieve the purpose of only one damping peak,moreover,when the layer weight ratio was 1/2/2,the width of effective damping temperature domain could also reach 71.99℃.3.BA and ST copolymerization emulsion in random copolymerization system was selected as the basic emulsion,and a series of fillers and auxiliaries were added to prepare water-based damping coating,it was found that the damping performance of 400-mesh mica powder with larger particle size was significantly improved,and the effective damping temperature range was 61.01℃.The number of fixed mica powder mesh is 400mesh,and the widest effective damping temperature range is 74.64℃ when the mass ratio is 40%.