Effect of inorganic pigments on polymer interdiffusion in low-Tg latex films

This thesis examines the influence of inorganic pigments on latex film formation. We carried out fluorescence resonance energy transfer measurements on latex films for following the extent of inter-particle polymer diffusion. We found that large calcium carbonate particles (300 nm x 1,000 nm) had little effect on the polymer diffusion rate for films containing up to 80 wt % filler, whereas 25 nm silica particles had a significant influence in poly(methyl methacrylate-co-2-ethylhexyl acrylate) latex films. We also examined the influence of silica particle size on this rate in poly(butyl methacrylate) latex films. We found that the 12 and 25 nm SiO₂ particles significantly affect the extent of mixing with increasing amounts of filler. The rate decreases as the filler size decreases. We propose that there is a low mobility polymer layer near the filler surface than the bulk polymer, and that the small silica particles can also act as obstacles.