MEASURING BACKBONE ACTIVATION-ENERGY AT POLYMER-POLYMER INTERFACES DURING LATEX FILM FORMATION BY USING A PHOTON TRANSMISSION METHOD

A photon transmission method was used to probe the evolution of optica l clarity during film formation from hard latex particles. The latex f ilms were prepared from poly (methyl methacrylate) (PMMA) particles, a nnealed at elevated temperatures in various time intervals above glass transition (T-g). Scanning electron microscopy (SEM) was used to dete ct the variation in physical structure of annealed films. In order to mimic the latex film formation process, Monte Carlo simulations were p erformed for photon transmission through a rectangular lattice. The nu mber of transmitted (N-tr) and scattered (N-sc) photons are calculated as a function of disappeared particle-particle interfaces. The increa se in the transmitted photon intensity (I-tr) is attributed to the inc rease in ''crossing density'' at the junction surface. The backbone ac tivation energy (Delta E) was measured and found to be around 33.4 kca l mol(-1) for a partially relaxing polymer chain across the junction s urface. (C) 1998 Elsevier Science Ltd. All rights reserved.