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The synthesis of a poly(diethylaminoethyl methacrylamide) (BP), based on a lineal methacrylamide with diethylaminoethyl branches was carried out. Thermal behavior was studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Relatively high thermal stability is found. Blends with poly(methylmethacrylate) (PMMA), poly(acrylic acid) (PAA) and poly(monomethyl itaconate) (PMMI) were prepared. Their thermal properties in blends were studied together with miscibility, in order to improve thermal properties of vinylic polymer blends. An increase of thermal stability was found for certain blend compositions. By FTIR analysis, higher band displacements were found for low BP compositions. AFM and molecular simulation analysis were carried out in order to elucidate the structural origin leading to thermal stability and miscibility increases. Hydrophobic interactions among methyl end groups of BP and methylene groups of vinylic polymers should be the responsible of miscibility and thermal stability increases. [ABSTRACT FROM PUBLISHER]

The crystallization behavior of two molecular weight poly(ethylene oxide)s (PEO) and their blends with the block copolymer poly(2-vinyl pyridine)- b-poly(ethylene oxide) (P2VP- b-PEO) was investigated by polarized optical microscopy, thermogravimetric analysis, differential scanning calorimetry, and atomic force microscopy (AFM). A sharp decreasing of the spherulite growth rate was observed with the increasing of the copolymer content in the blend. The addition of P2VP- b-PEO to PEO increases the degradation temperature becoming the thermal stability of the blend very similar to that of the block copolymer P2VP- b-PEO. Glass transition temperatures, Tg, for PEO/P2VP- b-PEO blends were intermediate between those of the pure components and the value increased as the content of PEO homopolymer decreased in the blend. AFM images showed spherulites with lamellar crystal morphology for the homopolymer PEO. Lamellar crystal morphology with sheaf-like lamellar arrangement was observed for 80 wt% PEO(200M) and a lamellar crystal morphology with grain aggregation was observed for 50 and 20 wt% blends. The isothermal crystallization kinetics of PEO was progressively retarded as the copolymer content in the blend increased, since the copolymer hinders the molecular mobility in the miscible amorphous phase. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Phenoxyethyl methacrylate (POEMA) and butyl methacrylate (BMA) were copolymerized by free-radical copolymerization using α,α'-azobisisobutyronitrile (AIBN) in 2-butanone solution at 333±1 K. Copolymers were characterized by FTIR, 1H-NMR and 13C-NMR spectroscopic methods and by comparison of the spectra with the corresponding homopolymers. Thermogravimetric analysis of the copolymers was carried out in order to know their thermal stability. Copolymer composition was established by 1H-NMR analysis. Monomer reactivity ratios (MRR) were computed using the classical Fineman - Ross (FR) and Kelen - Tudos (KT) procedures. MRR were also estimated using a nonlinear computational fitting procedure, known as reactivity ratios error in variable model (RREVM). The mean sequence lengths of the copolymers were estimated and suggest that random copolymers were obtained. [ABSTRACT FROM AUTHOR]

The free radical copolymerization of phenoxyethyl methacrylate (POEMA) and glycidyl methacrylate (GMA) was carried out using α,α'-azobisisobutyronitrile (AIBN) in 2-butanone solution at 333 ± 1 K. The copolymers were characterized by FTIR, 1H-NMR and 13C-NMR spectroscopic methods. Thermal properties of the copolymers were also studied by thermogravimetric analysis (TGA). The compositions of the copolymers were established by 1H-NMR analysis. The monomer reactivity ratios were computed using the Fineman-Ross (F-R) and Kelen-Tüdos (K-T) methods. These parameters were also estimated using a nonlinear computational fitting procedure, known as reactivity ratios error in variable model (RREVM). The mean sequence lengths determination indicates that the copolymers obtained are random in nature. Differences in the reactivity ratios obtained by the classical methods and RREVM were observed. GMA is more reactive than POEMA and although the copolymers are random, some tendency to GMA small block formation is reported. [ABSTRACT FROM AUTHOR]

Adsorption of As (V) by poly ( N -octyl-4-vinylpyridinium) bromide (P4VPyC8), used as solid phase, was studied. Determination of As (V) was carried out by direct measurement of the fluorescence intensity on the solid phase. Adsorption variables were optimized for obtaining optimum values of pH and agitation time, where pH 9.0 and 60 min were established as optimum values. The adsorption of arsenic (V) was characterized by infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. It was found that the fluorescence of the solid phase increases as the concentration of arsenic increases. Linearity was observed in the concentration range 6.80 to 90.0 μg L − 1 . The detection limit for determination of As (V) by this method was 2.24 μg L − 1 and the relative standard deviation (RSD) was 1.72%. The amount of retained As (V) was 0.154 mg/g of solid phase. The determination of As (V) in a sample of tap water by this method was well compared with the value reported by an external certified laboratory. Therefore, the method of analysis proposed here could be used as a screening methodology for monitoring the fulfillment of the norm for arsenic concentration in tap water. [ABSTRACT FROM AUTHOR]