Synthesis Of Polymer Latex With Composite Structure And Fabrication Of Waterborne Damping Coatings

Waterborne damping coatings are a new type of damping materials,which have good construction characteristics and environmental protection characteristics.According to the principle of designing polymer latex particles,the preparation of polymer latex with special composite structures is the key to the preparation of high-performance waterborne damping coatings.In this dissertation,different synthetic methods were designed based on the emulsion polymerization.Hindered phenol/polymer composite latex and poly(styrene-acrylate)latex with gradient structure were synthesized.The polymerization process and structure of latex particle were systematically studied.Based on the effect of the damping properties of the latex film,a synthetic poly(styrene-acrylate)latex was used as a film-forming resin to prepare a waterborne damping coating with excellent overall performance.The main work of this paper is as follows:(1)Synthesis of hindered phenol/polymer composite latex:Through the design of compatibility matching and emulsion polymerization method,hindered phenol/polymer latex was synthesized by emulsifying the monomer with hindered phenol and using the method of seed semi-continuous emulsion polymerization/monomer pre-emulsification.The kinetics of the polymerization process with different hindered phenol-245 addition amounts were studied,and the structure of the polymer latex particles was characterized.The results showed that the hindered phenol-245 can be in-situ with the polymer latex particles,and the emulsion polymerization process follows the traditional emulsion polymerization mechanism.The synthesized composite latex has good film-forming properties.The study on the structural properties of the hindered phenol/poly(styrene-acrylate)composite latex film found that the in-situ compounding of the hindered phenol and the latex polymer is advantageous to increase the efficiency of allogeneic hydrogen bond formation between the two.The energy loss caused by the constant breakage and formation of hydrogen bonds between the hindered phenol and polymer matrix enhances the damping properties of the material.When the amount of hindered phenol-245 was 30%of the total mass fraction of the polymerized monomers,the maximum loss factor of the composite latex reached 2.69,which was 60.1%higher than that before the modification;The effective damping temperature range has reached 112?,which is 77.8%higher than before modification.(2)Synthesis of high performance poly(styrene-acrylate)latex with gradient structure:By optimizing the process in emulsion polymerization,combining the main monomer composition design and functional monomer design,the stability of the polymer emulsion is improved,and the interface adhesion properties between the emulsion polymer and the substrate is improved.On this basis,the power feeding method was introduced into the emulsion synthesis.The dynamic mechanical analysis of the latex film showed that the gradient distribution of the copolymer composition in the latex particles can effectively broaden the effective damping temperature range of the latex film;Finally,amplification experiments were performed to verify the stability of the process.(3)Fabrication of bakeable and high-viscosity waterborne damping coatings:The above-mentioned synthetic polymer latex was used as a film-forming resin.Through formulation of the filler composition and design of the formulation of the auxiliary agent,a high-viscosity and bakeable waterborne damping coating was prepared.On this basis,expanded graphite and diatomite were selected as functional fillers,and microchannels inside the coating were constructed to provide a path for moisture overflow during coating baking and quick-drying processes.And the problem that the surface of the coating appears cracking or foaming after fast baking drying when the damping coatings are thick coated is solved;finally,through the screening of the additive type and the determination of the optimal addition amount,a complete formulation of bakeable thick waterborne damping coating was obtained.The performance of the damping coating was tested according to industry standards.