Photophysical study in blends of poly(alkyl methacrylate-co-styrene)/ polystyren

2019-08-14 09:53:03

analysis Ps blends copolymer spectroscopy

责任者: De Andrade, Marcelo L.;Atvars, Teresa D.Z. 单位: Instituto de Quimica, Universidade Estadual de Campinas, Campinas, Sao Paulo, Brazil 来源出处: Macromolecules,2004,37(24):9096-9108 摘要: The morphology of blends of poly(alkyl methacrylate-co-styrene)/polystyrene [XMAS/PS; X = M (methyl), E (ethyl)] was studied at the microscopic level (micrometric scale) by differential scanning calorimetry (DSC), dynamic-mechanical analysis (DMA), and epifluorescence microscopy (EFM) and at the nanoscopic scale by steady-state and time-resolved fluorescence emission spectroscopy (FES). Timeresolved energy transfer analysis was used to probe the interpenetration of molecular chains. The copolymers MMAS and EMAS (approximate content in mol %: 78% of methacrylate units; 22% of styrene units) covalently labeled with 9-vinylanthracene units ( [less-than or equal to] 0.1%), as fluorescent comonomer (fluorophore), were synthesized by emulsion polymerization and were characterized by FTIR, 1H NMR, 13C NMR, TGA, GPC, DSC, DMA, UV-vis, and FES. Films of copolymer blends were prepared by casting from dilute chloroform solutions with compositions of 5, 20, 50, 80, and 95 wt % of copolymer. Some miscibility was observed for the blends of XMAS/PS containing 5, 20, and 95 wt % of copolymer. Interaction strength in blends increased with the size of aliphatic chain of the ester group in the copolymer. Blends with 50 wt % of copolymer are always immiscible. Two values of glass transition temperatures were observed by DSC and DMTA. MMAS/PS and EMAS/PS blends of copolymer-richer compositions (95 and 80 wt %) show fluorescence lifetimes with broader distributions, suggesting a wider distance distribution of interlumophoric groups. 关键词: Polystyrenes;Morphology;Dynamic mechanical analysis;Synthesis (chemical);Energy transfer;Approximation theory;Fourier transform infrared spectroscopy;Nuclear magnetic resonance spectroscopy;Thermogravimetric analysis;Differential scanning calorimetry;Emission spectroscopy;Fluorescence emission spectroscopy (FES);Aliphatic chains;Time-resolved fluorescence;Broader distributions