Water-based Polymer Coating Preparation For The Polyolefin Matrix And Structural Performance Research

With increased need of developing environmentally benign (no pollution of hazardous materials into air, water or soil from a coatings) coatings, studying preparation, structure and properties of waterborne coatings directly used on polyolefms substrate is becoming more and more important. The key point is to enhance the wettability and adhesion of the coatings on the substrate. In this dissertation, methods of blending two polymer latex with chemically complementary structure and transferring of solvent-based polymer solution to water-based polymer solution were adopted. The structure and properties of the latex, the solution as well as the formed coatings were studied.Two copolymers, poly(methyl methacrylate-co-butyl acrylate-co-methacrylic acid) and poly(methyl methacrylate-co-butyl acrylate-co-N-2-pyrrolidone) with complementary chemical structure were synthesized through conventional emulsion polymerization using K2S208 as initiator and Soditn Dodecyl Suifonate as surfactant. Then, the composition of the obtained copolymers was demonstrated by 'H-NMR. Viscosity, surface tension and wetting behavior on PE substrate of the polymer emulsion blends were studied. The results show that emulsion blending will decrease surface tension, increase viscosity and lead to better wettability on PE substrate. By means of SEM, FTIR, DSC and tensile measurement, structure and properties of the coatings on PE substrate were also investigated. The results indicate that coatings formed from the blending of polymer latex coalesce well and produced films with50promoted thermal and tensile property.Copolymers containing carboxyl and pyrrolidone groups were synthesized through solution polymerization, using AIBN as initiator and alcohol as solvent. Deionized water and NH4OH(lmass%) were added to the obtained polymer solutions respectively ,to get water-based polymer solutions. It is found that the neutralization of carboxyl groups and carboxyl contents influence the transferring degree of solvent-based systems to waterborne systems, result in different stability. The results of measurements of XPS, contact angle, surface energy and shear stress of the coatings adhesion on PE substrate show that water plays a very important role on surface structure and properties of coatings. Surface energy of coating formed from solutions added water and lmass% NH4OH goes up. Also, polar or nonpolar components of coatings on PE substrate was a function of depth profile, on PE substrate, polar or nonpolar components gradient from surface (air and film) to interface (film and substrate). Substrate may also be a factor which influences surface structure and properties of coatings, surface energy and oxygen atomic concentration are different on surface of the coatings formed on PE and glass substrate.