| The surface properties of homo-poly(methyl methacrylate) (PMMA) and polystyrene-random-poly(methyl methacrylate) (PS-r-PMMA) copolymers were studied using modulated differential scanning calorimetry (MDSC), thermogravimetric analysis (TGA) and Fourier transformed infrared spectroscopy (FT-IR). For homo-PMMA, the tacticity (syndio- and iso-) was found to affect the configuration and thermal stability of the polymer adsorbed on silica. For PS-r-PMMA, the composition of the copolymer affected the adsorption and thermal transition in the polymers adsorbed on silica.; The segmental mobilities of the adsorbed dry PS-r-PMMA copolymer films were investigated by MDSC. The thermal transitions in the glass transition region of the adsorbed chains were found to be broad and structured (typically 100–160°C), representative of adsorbed polymer segments that were spatially heterogeneous. The transitions were shifted to higher temperatures with increases in the more strongly adsorbing MMA units.; For homo-PMMA, the effects of tacticity, annealing, methanol treatment and type of silica surface treatment were investigated. It was found that annealing can increase the thermal stability of adsorbed PMMA, but methanol treatments have different effects on adsorbed iso- and syndiotactic PMMA's. FT-IR studies of thin layers of iso-PMMA on silica helped in the understanding of the annealing process and low-temperature degradation. The effects of drying, solvent and PMMA tacticity on the configuration of adsorbed PMMA layers were also studied by FT-IR. |
