EFFECTS OF CARBOXYMETHYL CELLULOSE AND ETHYL(HYDROXYETHYL) CELLULOSE ON SURFACE STRUCTURE OF COATINGS DRAWN DOWN FROM POLYSTYRENE SUSPENSIONS

摘要

The surface structure of coating layers drawn down from polystyrene suspensions was investigated. The effects oftwo different soluble cellulose ethers, ethyl(hydroxyethyl) cellulose and carboxymethyl cellulose, were compared.Each of the suspensions was investigated at three different concentration levels of the soluble cellulose ethers. AnAtomic Force Microscope was used to investigate the surface structure of coating layers drawn down on polyestersubstrates from aqueous polystyrene (PS) suspensions. The surface structure was interpreted by calculating the pairdistribution function n g(r) , where r is the radius of a ring centered at a particle.The colloidal stability of the polystyrene suspensions was also investigated by means of rheology. The relativeviscosity was calculated in order to elucidate the colloidal stability and degree of flocculation.Ethyl(hydroxyethyl) cellulose possesses temperature responsive properties, and the suspensions were investigated attwo temperatures, 23 °C and 55 °C. The effects of the concentration of cellulose ether on the relative viscosityindicated that ethyl(hydroxyethyl) cellulose, at least at the higher temperature, destabilized the PS suspensions by acapillary induced phase separation mechanism