Miscible blends of poly(vinyl phenyl ketone hydrogenated) and poly(styrene-co-4-vinylpyridine)

Miscibility behavior over a wide composition range was detected for polymer blends of poly(vinyl phenyl ketone hydrogenated) (PVPhKH) with poly(styrene-co-4-vinylpyridine) (PS-co-4VPy). Differential scanning calorimetry (DSC) and thermo mechanical analysis (TMA) reveal that each composition has only one glass transition temperature. The variation of the glass transition temperature with composition for PVPhKH/PS-co-4VPy miscible blends follows the Gordon-Taylor equation. FTIR analysis of this binary system indicates the existence of hydrogen bonding between pyridine ring of PS-co-4VPy and hydroxyl groups insert into PVPhKH. This specific interaction has a decisive influence in the phase behavior of PVPhKH/PS-co-4VPy blends. � 2004 Elsevier Ltd. All rights reserved

Miscible blends of poly(vinyl phenyl ketone) and poly(4-vinyl phenol)

An analysis by differential scanning calorimetry, modulated differential scanning calorimetry, and Fourier transform infrared spectroscopy (FTIR) indicates that blends of poly(vinyl phenyl ketone) (PVPhK) and poly(4-vinyl phenol) (P4VPh) are miscible at ambient temperature. Miscibility, ascertained, is supported by the existence of a single glass transition for each composition of the PVPhK/P4VPh blends. The FTIR spectroscopy analysis demonstrates the formation of hydrogen bonds between carbonyl groups of PVPhK and hydroxyl groups of P4VPh. This specific interaction has a crucial role on the miscibility behavior of PVPhK/P4VPh blends. The evolution of the glass transition of the PVPhK, P4VPh, and its blends as a function of mixture composition shows negative deviations with to respect to the ideal mixing rule, and both Fox and Gordon-Taylor equations predict this behavior successfully. © 2006 Wiley Periodicals, Inc

Smart copolymeric nanohydrogels: Synthesis, characterization and properties

Novel smart pH-sensitive copolymeric hydrogels have been synthesized by inverse microemulsion polymerization of p-nitro phenol acrylate (NPA) and N-isopropylacrylamide (NIPA) using Aerosol (AOT) as a surfactant and ethylene glycol dimethacrylate (EGDMA) as a crosslinking agent. The polymerization reaction was performed in presence of an oil-soluble salt to reduce the dimensions of the micellar diameter. The average particle diameter and the particle size distribution of the nanogels were measured in acetone at 25 °C by quasielastic light scattering (QLS) showing average diameter of 33 nm. The nanogels were characterized by FTIR-ATR, H1 NMR, UV-vis spectroscopy and DSC. These nanoparticles had shown a selective swelling-collapse response to external pH changes. © 2008

Ionomer synthesis by emulsion polymerization of styrene and sodium acrylate

The emulsion copolymerization of styrene and sodium acrylate is reported using either a water-soluble initiator (potassium persulfate, or KPS), or an oil-soluble one [2,2-azoisobutyronitrile (AIBN)]. Reaction rates are fast with both KPS and AIBN. With KPS, conversions >90% are achieved in 50 min, with AIBN, conversions reach 85% in 100 min. Particle size, measured by quasielectric light scattering (QLS), increases with conversion. Particle size in final latices is ∼ 70-80 nm. Copolymer formation is confirmed by infrared (IR) spectroscopy, plasma emission spectroscopy (PES), and scanning electron microscopy (SEM). IR and PES indicate that mainly sodium acrylate reacts at the beginning of the reaction and then styrene is incorporated in the copolymer backbone. The copolymer produced with KPS contains more sodium acrylate than the one made with AIBN. These differences can be explained in terms of the reactivities and partitioning (local concentrations) of the monomers and of the type of initiator used. Thermomechanical analysis (TMA) of the copolymers reveals two transitions: one at ∼ 100°C, which is due to the glass transition temperature (Tg) of polystyrene blocky segments in the copolymer, and another one at higher temperatures, which is associated to the Tg of segments composed of alternated sodium acrylate and styrene units. The higher-temperature transition shifts to lower values as the reaction proceeds because these segments become richer in styrene. © 1997 John Wiley & Sons, Inc

The effect of synthesis methods on the mechanical properties of self-crosslinkable poly(n-butyl methacrylate-co-N-methylolacrylamide) films

The effects of particle size and parent polymer characteristics on the mechanical properties, gel fraction, and swelling index of self-crosslinkable poly(n-butyl methacrylate-co-N-methylolacrylamide) films made by two-stage emulsion or microemulsion polymerization in the presence of variable amounts of the chain transfer agent, n-butyl mercaptan, are reported here. In films prepared with latexes made by microemulsion polymerization, the crosslinking degree increased greatly on curing; by contrast, in those made by emulsion polymerization, the crosslinking degree practically did not increase after curing. Stress-strain tests of uncured and cured films indicate that microemulsion-made films are tougher than the emulsion-made films. © 2011 Wiley Periodicals, Inc

Synthesis, characterization and magnetic properties of Co@Au core-shell nanoparticles encapsulated by nitrogen-doped multiwall carbon nanotubes

The synthesis of superabsorbent poly(sodium acrylate) by semicontinuous inverse heterophase polymerization is reported here. In this process, an aqueous solution of sodium acrylate, initiator, and a cross-linking agent is dosed at a controlled rate over an organic solution containing surfactant. These nanogels exhibit a large swelling ratio (compared to the dry nanoparticles synthesized by inverse microemulsion polymerization), which increase to some extent with temperature, but then at ca. 30°C, they de-swell slightly. Possible explanations to this behavior are the release of residual stresses originated during nanoparticles purification and drying, the association-dissociation of ionic clusters, and the thermoelastic inversion point of the elastic modulus of the nanogels. " 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.",,,,,,"10.1002/mren.201400066",,,"http://hdl.handle.net/20.500.12104/44946","http://www.scopus.com/inward/record.url?eid=2-s2.0-84926479797&partnerID=40&md5=5f6003493ec2f73239d6f53521ae1091",,,,,,"2",,"Macromolecular Reaction Engineering",,"12

Investigation and analysis of urban noise for sustainability

The emulsion copolymerization of styrene and sodium acrylate is reported using either a water-soluble initiator (potassium persulfate, or KPS), or an oil-soluble one [2,2-azoisobutyronitrile (AIBN)]. Reaction rates are fast with both KPS and AIBN. With KPS, conversions >90% are achieved in 50 min, with AIBN, conversions reach 85% in 100 min. Particle size, measured by quasielectric light scattering (QLS), increases with conversion. Particle size in final latices is ? 70-80 nm. Copolymer formation is confirmed by infrared (IR) spectroscopy, plasma emission spectroscopy (PES), and scanning electron microscopy (SEM). IR and PES indicate that mainly sodium acrylate reacts at the beginning of the reaction and then styrene is incorporated in the copolymer backbone. The copolymer produced with KPS contains more sodium acrylate than the one made with AIBN. These differences can be explained in terms of the reactivities and partitioning (local concentrations) of the monomers and of the type of initiator used. Thermomechanical analysis (TMA) of the copolymers reveals two transitions: one at ? 100°C, which is due to the glass transition temperature (Tg) of polystyrene blocky segments in the copolymer, and another one at higher temperatures, which is associated to the Tg of segments composed of alternated sodium acrylate and styrene units. The higher-temperature transition shifts to lower values as the reaction proceeds because these segments become richer in styrene. " 1997 John Wiley & Sons, Inc.",,,,,,,,,"http://hdl.handle.net/20.500.12104/42392","http://www.scopus.com/inward/record.url?eid=2-s2.0-0031257309&partnerID=40&md5=0e4e1d08f0a5f61b9c74331a3974930f",,,,,,"5",,"Journal of Applied Polymer Science",,"87

Polymer nanocomposites containing carbon nanotubes and miscible polymer blends based on poly[ethylene-co-(acrylic acid)]

Four binary polymer blends containing poly [ethylene-co-(acrylic acid)] (PEAA) as one component, and poly(4-vinyl phenol-co-2-hydroxy ethyl methacrylate) (P4VPh-co-2HEMA) or poly(2-ethyl-2-oxazoline) (PEPx) or poly(vinyl acetate-co-vinyl alcohol) (PVAc-co-VA) or poly (vinylpyrrolidone-co-vinyl acetate) (PVP-co-VAc) as the other component were prepared and used as a matrix of a series of composite materials. These binary mixtures were either partially or completely miscible within the composition range studied and were characterized by differential scanning calorimetry (DSC) and Fourier transformed infrared spectroscopy (FTIR). Carbon nanotubes (CNTs) were prepared by a thermal treatment of polyester synthesized through the chemical reaction between ethylene glycol and citric acid over an alumina boat. High resolution transmission electron microscopy (HRTEM) was used to characterize the synthesized CNTs. Films of composite materials containing CNTs were obtained after evaporation of the solvent used to prepare solutions of the four types of binary polymer blends. Young's moduli of the composites were obtained by thermomechanical analysis at room temperature. Only one glass transition temperature was detected for several compositions on both binary blends and the composite material matrices. Evidence of hydrogen bond formation was recorded for both miscible blends and composite materials. The degree of crystallinity and Young's moduli of the CNT-polymer composites increased compared to the single polymer blends. © 2008 Wiley Periodicals, Inc

Synthesis of poly(Sodium Acrylate) nanogels via semicontinuous inverse heterophase polymerization

The synthesis of superabsorbent poly(sodium acrylate) by semicontinuous inverse heterophase polymerization is reported here. In this process, an aqueous solution of sodium acrylate, initiator, and a cross-linking agent is dosed at a controlled rate over an organic solution containing surfactant. These nanogels exhibit a large swelling ratio (compared to the dry nanoparticles synthesized by inverse microemulsion polymerization), which increase to some extent with temperature, but then at ca. 30°C, they de-swell slightly. Possible explanations to this behavior are the release of residual stresses originated during nanoparticles purification and drying, the association-dissociation of ionic clusters, and the thermoelastic inversion point of the elastic modulus of the nanogels. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Tensile properties of self-crosslinkable poly(n-butyl methacrylate-co-N- methylolacrylamide) films prepared by emulsion and microemulsion latexes0

The gel content, swelling degree and mechanical properties of self-crosslinkable poly(n-butyl methacrylate-co-N-methylolacrylamide) films made by two-stage emulsion (using sodium dodecyl sulfate as surfactant) or microemulsion (using cetyltrimethylammonium bromide as surfactant) polymerization processes in the presence of variable amounts of the chain transfer agent, n-butyl mercaptan, are reported here. Latexes made by microemulsion polymerization contain much smaller nanoparticles with lower amount of gel than those obtained by the emulsion process. Stress-strain tests in uncured and cured films indicate that microemulsion-made films are tougher and exhibit smaller deformations at break