T. Tamai et al., Effect of cross-linking on polymer diffusion in poly(butyl methacrylate-co-butyl acrylate) latex films, MACROMOLEC, 32(19), 1999, pp. 6102-6110
The effect of cross-linking on intercellular polymer diffusion in poly(buty
l methacrylate-co-butyl acrylate-co-ethylene glycol dimethacrylate) latex f
ilms containing 0.1-4 mol % ethylene glycol dimethacrylate (EGDMA) as a cro
ss-linking agent was monitored by fluorescent energy-transfer measurements
and by atomic force microscopy. The presence of cross-links in the latex pa
rticles limits the extent of polymer interdiffusion. The extent of mixing c
aused by this polymer diffusion decreased with increasing levels of cross-l
inking. Even, however, in films containing 4 mol % EGDMA, significant polym
er diffusion occurred. To explain polymer diffusion in latex films with 100
% gel content, we imagine that the intercellular mixing is caused by diffus
ion of dangling polymer chains anchored in the cross-linked network. These
cross-linked latex particles form tough elastomeric films (with T-g estimat
ed to be 10 degrees C), characterized by high tensile strength and substant
ial elongation to break (>100% elongation). The films have poor resistance
to organic solvents.