CONTROL OF LOCATION OF FUNCTIONAL SITES FOR THERMOSETTING LATEXES

摘要

The location of hydroxyl functionality was investigated for thermosetting acrylic latexes. Three series of core-shell hydroxyl functionalized latexes were synthesized, and then crosslinked. Large and small latex particles with and without hydroxyl functionality were also synthesized and characterized. Large and small latex particles with and without hydroxyl functionality were blended together, and the latexes were crosslinked. In both cases the location of hydroxyl groups either within latex particles (core/shell) or on the small or large latex particles had an effect upon the thermomechanical properties and hence the ultimate performance of the crosslinked latexes. The introduction of hydroxyl groups during the shell polymerization resulted in a higher crosslinking density, but a lower Tukon hardness and tensile properties. The packing of the large and small latexes were dependent on small to large particle ratio, and in addition had an effect upon the speed of film formation. The higher concentration of hydroxyl groups in the small latex particles contributed more to the tensile properties of the latexes than the functionality of the large particles.