PARTICLE-SIZE AS IT RELATES TO THE MINIMUM FILM FORMATION TEMPERATURE OF LATTICES

The relationship between the particle sizes and minimum film formation temperature (MFT) of polymer colloids was studied. Early workers had developed theoretical models predicting small particle colloids should coalesce easier and have lower MFTs than those of large colloids. Early published work examining this question reported that MFT was independent of particle size. In 1990, Eckersley and Rudin, using monodisperse acrylic latexes ranging from 148-1234 nm, reported finding that MFT was a function of particle size as predicted. We synthesized a series of monodisperse acrylic copolymer latexes ranging from 63-458 nm and measured MFTs of these latexes and blends of them. We have also found particle size does affect MFT with small particle polymer colloids having lower MFTs than larger ones. Our results differ somewhat in that the MFTs of our latexes are below the glass transition temperatures (T(g)) of the polymers while Eckersley et al. report MFTs above T(g).