THE EFFECT OF SOLID CONTENT ON LATEX COALESCENCE AND FILM FORMATION -STEADY-STATE ENERGY-TRANSFER STUDY WITH FLUORESCENCE-LABELED POLYMERS

The steady-state fluorescence technique was used to examine the healin g and interdiffusion of polymer molecules as a function of solid conte nt during annealing of latex films above the glass transition (T-g). F ilms were prepared from a mixture of naphthalene (N)- and pyrene (P)-l abeled poly (methy methacrylate) (PMMA) latex particles. Above T-g, in terdiffusion of polymer chains was observed by detecting the steady-st ate energy transfer from excited naphthalene to pyrene molecules. Vari ous latex films with different latex content were used to measure the critical occupation percent for the reliable steady-state fluorescence measurements. Diffusion activation energies in these latex films were measured and found to be around 30 kcal/mol, which was attributed to the backbone motion of PMMA chains. (C) 1996 John Wiley & Sons, Inc.