Sprecher
Beschreibung
Waterborne latex films, obtained from the dispersion of latex particles, are of particular interest due to the non-content of volatile organic compounds (VOC), often mandatory under environmental legislation. To prepare efficient and solvent-free coatings with a low glass-transition temperature but higher mechanical strength, we have integrated hydrophilic layers (Acrylic acid/ Poly(acrylamide)) around the hydrophobic cores (mixture of Methyl methacrylate and Butyl acrylate). Latex particles have been synthesized using emulsion polymerization. Polymer latex films have been prepared in the next step by evaporating water in a humidity chamber. The structure formation of polymer latex films in the dry state (crystallinity) and in the re-swelled state (change in crystallinity and whitening or blushing) has been studied using Small-Angle Neutron Scattering (SANS), which reveals FCC-like structure formation by the latex film, with better ordering in the inclusion of the hydrophilic shell. The interdiffusion between the latex particles has been studied by mixing H/D polymers in the films. The films were annealed at high temperatures to initiate the kinetics of mixing. The presence of hydrophilic hairy layers promotes the interdiffusion of the polymers. The transfer of polymer chains through interparticle boundaries vanishes the crystalline structure and results in the formation continuous material.