Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Ionomer (3)
- Composite (2)
- Ionomers (2)
- Miscibility (2)
- POLYMERS (2)
-
- Stearate introduction (2)
- Sulfonated EPDM (2)
- X-ray scattering (2)
- 4-PHENYLENE OXIDE) (1)
- 6-DIMETHYL-1 (1)
- ALKALI METAL COMPLEXES (1)
- ALKENES (1)
- ALKYLATED AROMATICS (1)
- AROMATICS (1)
- BREMSSTRAHLUNG (1)
- Blends (1)
- CHEMICAL REACTIONS (1)
- COMPLEXES (1)
- CROSS-LINKING (1)
- CRYSTAL STRUCTURE (1)
- Chain collapse (1)
- DECOMPOSITION (1)
- DISSOCIATION (1)
- ELECTROMAGNETIC RADIATION (1)
- Electrical conductivity (1)
- HYDROCARBONS (1)
- ION-DIPOLE INTERACTIONS (1)
- Liquid crystalline polymers (1)
- MATERIALS SCIENCE (1)
- MISCIBILITY ENHANCEMENT (1)
- Publication Year
Articles 121 - 149 of 149
Full-Text Articles in Engineering
Solution Behavior Of Lightly Sulfonated Polystyrene And Poly(Styrene-Co-4-Vinylpyridine) Complexes In Dimethylformamide, Robert Weiss
Solution Behavior Of Lightly Sulfonated Polystyrene And Poly(Styrene-Co-4-Vinylpyridine) Complexes In Dimethylformamide, Robert Weiss
Robert Weiss
No abstract provided.
Drug Diffusion In Hydrophobically Modified N,N-Dimethylacrylamide Hydrogels, Robert Weiss
Drug Diffusion In Hydrophobically Modified N,N-Dimethylacrylamide Hydrogels, Robert Weiss
Robert Weiss
The use of hydrophobically modified hydrogels for drug release was investigated. Copolymers of N,N-dimethylacrylamide and 2-(N-ethyl-perfluorooctanesulfonamido) ethyl acrylate (FOSA) were prepared by free-radical polymerization. The drug release rates, dynamic swelling behavior, and pH sensitivities of copolymers ranging in composition from 0 to 30 mol% FOSA were studied. Pheniramine maleate, an ocular antihistamine, was used as the model drug substance. Hydrogels of DMA produced with increasing amounts of FOSA had a decreased equilibrium media content and exhibited a slower drug release rate. Early-time, late-time and Etters approximation drug diffusion coefficients ranged from 0.4×10−3 to 12.3×10−3 mm2/min. The diffusion of the drug …
The Control Of Ionic Interactions In Sulfonated Polystyrene Ionomers By Using Alkyl-Substituted Ammonium Counterions, Robert Weiss
The Control Of Ionic Interactions In Sulfonated Polystyrene Ionomers By Using Alkyl-Substituted Ammonium Counterions, Robert Weiss
Robert Weiss
Polystyrenes containing up to about 20 mol % sulfonic acid are reproducibly and readily prepared by the sulfonation of polystyrene at 50°C with acetyl sulfate in 1,2-dichloroethane solution. The metal salts of sulfonated polystyrene possess extremely high melt viscosities and are soluble in single solvents such as toluene and THF only at very low sulfonate levels. Such properties are the result of the very strong ion-dipole interactions among the metal sulfonate groups. Such strong interactions can be substantially reduced through the neutralization of the sulfonic acid with ammonia and, most especially, relatively simple low molecular weight amines. Sulfonated polystyrenes varying …
Characterization Of Zinc Stearate Plasticized Sulfonated Epdm By Real Time Saxs And Waxs, Robert Weiss, A. Sen, A. F. Galambos, J. T. Koberstein, T. P. Russell
Characterization Of Zinc Stearate Plasticized Sulfonated Epdm By Real Time Saxs And Waxs, Robert Weiss, A. Sen, A. F. Galambos, J. T. Koberstein, T. P. Russell
Robert Weiss
No abstract provided.
The Synthesis Of Conductive Nano-Composites By A Selective In Situ Polymerization Of Pyrrole Within The Lamellar Microdomains Of A Block Copolymer, M. C. De Jesus, Robert Weiss
The Synthesis Of Conductive Nano-Composites By A Selective In Situ Polymerization Of Pyrrole Within The Lamellar Microdomains Of A Block Copolymer, M. C. De Jesus, Robert Weiss
Robert Weiss
Electrically conductive nanocomposites were prepared by a selective in situ polymerization of pyrrole within the lamellae ionomeric microdomains of sulfonated poly(styrene-b-(ethylene-alt-propylene)), SEP, diblock copolymers. A conductivity of 10-3−10-1 S/cm was achieved parallel to the film surface for PPy concentrations from 5 to 11 wt % PPy. Although the microstructure of the block copolymer was not purposefully aligned, the conductivity was anisotropic, varying 1−2 orders of magnitude parallel and normal to the plane of the composite films. The in situ polymerization of pyrrole in the SPS microphase did not disrupt the texture of the block copolymer microstructure, though the interphase between …
Melt Processable, Polypeptide/ Ionomer Molecular Composites, Robert Weiss
Melt Processable, Polypeptide/ Ionomer Molecular Composites, Robert Weiss
Robert Weiss
No abstract provided.
Development Of Supported Ethanolamines And Modified Ethanolamines For Co2 Capture, Robert Weiss
Development Of Supported Ethanolamines And Modified Ethanolamines For Co2 Capture, Robert Weiss
Robert Weiss
Liquid amines can be immobilized within the pores of polymeric supports to provide a regenerable CO2 sorbent. This paper describes the capture of CO2 by a range of ethanolamines (primary, secondary, and tertiary) immobilized within the pores of high-surface-area poly(methyl methacrylate) beads. These supported amines were used to remove low concentrations (7.6 mmHg) of CO2 by a pressure swing absorption process, where low-pressure vacuum was used to desorb the CO2 and regenerate the sorbent. The effect on CO2 capture of modification of primary amines to secondary amines by reaction with acrylonitrile was also evaluated. The modified amines provided nearly a …
Sorption Of Iodine By Polyurethane And Melamine-Formaldehyde Foams Using Iodine Sublimation And Iodine Solutions, Robert Weiss
Sorption Of Iodine By Polyurethane And Melamine-Formaldehyde Foams Using Iodine Sublimation And Iodine Solutions, Robert Weiss
Robert Weiss
Iodine sorption by polyurethane (PU) and melamine-formaldehyde (MF) foams was studied using both iodine sublimation and iodine solutions with hexanes and toluene. In the sublimation process, the diffusion kinetics was investigated and the interaction between iodine and PU foams was characterized by DSC, TGA, Raman spectroscopy and electrical conductivity measurements. In the solution process, the equilibrium absorption followed the distribution law and the distribution coefficients varied depending on the solvent used. MF foam achieved no iodine absorption in both processes which can be attributed to the lack of charge–transfer interactions.
Characterization Of Ionomer Solutions. 1. Phase Behavior And Gelation Of Sulfonated Polystyrene Ionomers In Decalin, K. Chakrabarty, T. A. P. Seery, Robert Weiss
Characterization Of Ionomer Solutions. 1. Phase Behavior And Gelation Of Sulfonated Polystyrene Ionomers In Decalin, K. Chakrabarty, T. A. P. Seery, Robert Weiss
Robert Weiss
The phase behavior of solutions of the acid form of lightly sulfonated polystyrene in Decalin was affected by the total acid group concentration and by the number of acid groups per molecule. The upper critical solution temperatures (UCST) increased with total acid group content as a consequence of poorer solvent quality. The UCST also increased with increasing number of acid groups per molecule, which was attributed to a loss of configurational entropy due to the aggregation of the acid groups by hydrogen bonding
Current Topics In Liquid Crystalline Polymers, Robert Weiss
Current Topics In Liquid Crystalline Polymers, Robert Weiss
Robert Weiss
This chapter provides an overview of current researches on liquid crystalline polymers (LCP's). Topics include syntheses of main-chain and side-chain LCP's, structured characterization of LCP's and LCP networks and rheology and processing. Applications of LCP/polymer blends as self-reinforced polymers and electro-optical meterials are also discussed.
Melt Intercalation/Exfoliation Of Polystyrene--Sodium-Montmorillonite Nanocomposites Using Sulfonated Polystyrene Ionomers Compatibilizers, Robert Weiss
Robert Weiss
Quaternary ammonium salts of sulfonated polystyrene (SPS) were used as compatibilizers for melt intercalation of PS and pristine Na-montmorillonite. Tetra-octyl ammonium SPS and tetra-decyl ammonium SPS ionomeric compatibilizers produced significant exfoliation and a homogeneous dispersion of the polymer–clay nanocomposites. Wide angle X-ray diffraction and transmission electron microscopy were primarily used to characterize the morphology of the nanocomposites. Image analysis was used to measure the percentage exfoliation. Exfoliation increased with the increasing length of the alkyl chain of the ammonium counter-ion of the SPS ionomer. The nanocomposites containing ionomers exhibited higher storage moduli compared to nanocomposites without the compatibilizer.
Structure Pinning During Phase-Separation Of Polyamide/Ionomer Blends, Robert Weiss
Structure Pinning During Phase-Separation Of Polyamide/Ionomer Blends, Robert Weiss
Robert Weiss
No abstract provided.
Miscibility Enhancement Of Polystyrene And Poly(Alkylene Oxide) Blends Using Specific Intermolecular Interactions, Robert Weiss
Miscibility Enhancement Of Polystyrene And Poly(Alkylene Oxide) Blends Using Specific Intermolecular Interactions, Robert Weiss
Robert Weiss
Acid–base interactions were used to enhance the miscibility of blends of polystyrene and oligomeric poly(alkylene oxide). The polystyrene was modified by sulfonation of less than 5% of the styrene rings. The poly(alkylene oxides) were low molar mass polyethylene oxide chains (M = 900 and 6000) that were end capped with propyl amine groups. Blends of the poly(alkylene oxide) diamines with polystyrene were immiscible. Blends with the sulfonated polystyrenes were miscible due to proton transfer from the sulfonic acid groups to the basic amino groups of the functionalized poly(alkylene oxide). This was confirmed by FTIR. DSC and dynamic mechanical analyses were …
The Effect Of Tosylate Salts And Zinc Sulfonate Polystyrene Ionomer On The Thermal Stability Of Bisphenol A Polycarbonate, Robert Weiss
The Effect Of Tosylate Salts And Zinc Sulfonate Polystyrene Ionomer On The Thermal Stability Of Bisphenol A Polycarbonate, Robert Weiss
Robert Weiss
No abstract provided.
Phosphonate Ionomers Based On Phosphonylated Ethylene-Propylene Copolymer, Robert Weiss
Phosphonate Ionomers Based On Phosphonylated Ethylene-Propylene Copolymer, Robert Weiss
Robert Weiss
No abstract provided.
Polymer Blends Containing Liquid Crystals. A Review, Robert Weiss
Polymer Blends Containing Liquid Crystals. A Review, Robert Weiss
Robert Weiss
This paper reviews the literature of polymer blends containing low and high molar mass liquid crystals. Low molar mass liquid crystals have been used as plasticizers for thermoplastic polymers and in applications such as electrooptics, optical recording media, and membranes. High molar mass liquid crystalline polymers have been primarily used in polymer blends as processing aids and as an incipient reinforcing phase for “self-reinforced” materials. This review discusses the phase behavior, rheology, and mechanical properties of these blends.
Solution Viscosity Behavior Of Complexes Of Poly(Γ-Benzyl-L-Glutamate) With Lightly Sulfonated Polystyrene Or Its Zinc Salt, L. Shao, Robert Weiss, R. D. Lundberg
Solution Viscosity Behavior Of Complexes Of Poly(Γ-Benzyl-L-Glutamate) With Lightly Sulfonated Polystyrene Or Its Zinc Salt, L. Shao, Robert Weiss, R. D. Lundberg
Robert Weiss
The rheological behavior of solutions containing blends of poly(γ-benzyl-l-glutamate) (PBLG) and either the free acid or the zinc salt of lightly sulfonated polystyrene (SPS) was studied as a function of blend composition, polymer concentration, degree of sulfonation of the SPS, and the polypeptide molecular weight. The zinc salt of SPS formed a transition metal complex with the amine-end groups of the PBLG, and this resulted in an enhancement of the solution viscosity relative to a weighted average of the viscosities of the individual polymer solutions. The ZnSPS/PBLG solutions showed no anomalous time or shear dependencies. In contrast, solutions containing PBLG …
Viscoelastic Behavior Of Lightly Sulfonated Polystyrene Ionomers, Robert Weiss, J. J. Fitzgerald, D. Kim
Viscoelastic Behavior Of Lightly Sulfonated Polystyrene Ionomers, Robert Weiss, J. J. Fitzgerald, D. Kim
Robert Weiss
See Link
Formation Of Nanoparticles During Melt Mixing A Thermotropic Liquid Crystalline Polyester And Sulfonated Polystyrene Ionomers: Morphology And Origin Of Formation., Robert Weiss
Robert Weiss
The formation of nanoparticles and the mechanism of their formation in a blend of a thermotropic liquid crystalline polyester (LCP) and the zinc salt of a lightly sulfonated polystyrene ionomer (Zn-SPS) were investigated using Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and gas chromatography–mass spectroscopy (GC–MS). Transmission electron microscopy (TEM) and wide-angle X-ray diffraction (WAXD) were used to study the morphology of the blends and structure of nanoparticles. The origin of nanoparticle formation appeared to be related to the development of phenyl acetate chain ends on the LCP that arose due to a chemical reaction between the LCP and residual …
Nano-Composites Derived From Melt Mixing A Thermotropic Liquid Crystalline Polyester And Zinc Sulfonated Polystyrene Ionomers, Robert Weiss
Nano-Composites Derived From Melt Mixing A Thermotropic Liquid Crystalline Polyester And Zinc Sulfonated Polystyrene Ionomers, Robert Weiss
Robert Weiss
A nano-composite was produced by simply melt mixing a blend of a thermotropic liquid crystalline polyester (LCP) and the zinc salt of a lightly sulfonated polystyrene ionomer at 300 °C. The nano-particles, which were in the form of relatively uniform rectangular prisms of ca. 30 nm×30 nm×200 nm, formed from the LCP phase due to an ester-interchange reaction between the LCP and residual catalytic amounts of zinc acetate that were present from the neutralization step in the preparation of the ionomer. The nano-particles possessed a different crystal pattern and higher melting point than the parent LCP, and they were easily …
Blends Containing Liquid Crystalline Polymers: Preparation And Properties Of Melt-Drawn Fibers, Unidirectional Prepregs, And Composite Laminates, D. Dutta, Robert Weiss, K. Kristal
Blends Containing Liquid Crystalline Polymers: Preparation And Properties Of Melt-Drawn Fibers, Unidirectional Prepregs, And Composite Laminates, D. Dutta, Robert Weiss, K. Kristal
Robert Weiss
This paper discusses the effect of melt drawing on the mechanical properties and morphology of liquid crystalline polymer (LCP) and thermoplastic polymer blends. Extruded fibers and films of LCP/polymer blends were melt drawn to develop uniaxial orientation of the dispersed LCP phase. The longitudinal modulus increased with increasing draw. The increase in modulus was due to higher aspect ratio of the LCP fibrils and improved molecular orientation of the LCP chains within the fibrils. Laminated composites were prepared using the extruded sheets as prepregs. The mechanical properties and the coefficient of thermal expansion (CTE) of the prepreg and the laminates …
Physically Crosslinked Alkyl Acrylamide Hydrogels: Phase Behavior And Microstructure, Robert Weiss
Physically Crosslinked Alkyl Acrylamide Hydrogels: Phase Behavior And Microstructure, Robert Weiss
Robert Weiss
The volume phase transition and the microstructure of physically cross-linked hydrogels composed of either N,N-dimethylacrylamide (DMA) or N-isopropylacrylamide (NIPA) and 2-(N-ethylfluorooctanesulfonamido)ethyl acrylate, FOSA, were studied using differential scanning calorimetry (DSC), water swelling measurements (WS), and small-angle X-ray scattering (SAXS). DSC and WS measurements showed that FOSA/NIPA gels exhibited a volume phase transition (VPT) but that the FOSA/DMA gels did not. The temperature of the VPT (TVPT) for the FOSA/NIPA gels was lower than that for the covalent NIPA gel, and TVPT decreased and the transition broadened with increasing FOSA concentration. A peak in the SAXS structure factor indicated that the …
Conductive Polymer Blends Prepared By In Situ Polymerization Of Pyrrole, Robert Weiss
Conductive Polymer Blends Prepared By In Situ Polymerization Of Pyrrole, Robert Weiss
Robert Weiss
Electrically conductive polymer blends can be prepared by in situ polymerization of pyrrole within another polymer matrix. This may be accomplished using either electrochemical or chemical oxidative polymerization. This paper reviews the literature on this subject.
Molecular Interpretation Of Miscibility In Polyamide-6 Blends With Alkali Ionomers Of Sulfonated Polystyrene., Robert Weiss
Molecular Interpretation Of Miscibility In Polyamide-6 Blends With Alkali Ionomers Of Sulfonated Polystyrene., Robert Weiss
Robert Weiss
Blends of polyamide-6 with lithium ionomers of 9.8 and 5.4 mole percent sulfonated polystyrene, formed by combining solutions of these polymers, are miscible over a wide compositional range, but those with the equivalent sodium ionomers are not. The molecular origin of this difference is addressed by studying the far infared and infrared spectra of the blends and pure materials to follow changes in the interactions between the cations and their surroundings, and changes in the interactions between functional groups. Based on analysis of these spectra, a molecular level interpretation of the blending is proposed. The initial step involves both the …
Structure Development Of Phase Separated Polymer Blends Undergoing Simple Shear Flow, Z. J. Chen, M. T. Shaw, Robert Weiss
Structure Development Of Phase Separated Polymer Blends Undergoing Simple Shear Flow, Z. J. Chen, M. T. Shaw, Robert Weiss
Robert Weiss
No abstract provided.
Esr Evidence For Specific Solvation Effects In Ionomer Solutions, Robert Weiss
Esr Evidence For Specific Solvation Effects In Ionomer Solutions, Robert Weiss
Robert Weiss
No abstract provided.
Synthesis And Characterization Of Crosslinked Sulfonated Polystyrene Nanoparticles, Robert Weiss
Synthesis And Characterization Of Crosslinked Sulfonated Polystyrene Nanoparticles, Robert Weiss
Robert Weiss
Cross-linked polystyrene particles have applications in many fields such as ion exchange columns, fuel cell membranes, and catalysis, to name a few. Synthesis of these particles in smaller sizes offers various advantages due to the increased specific surface area. Polystyrene nanoparticles having volume-equivalent diameters in the range of 40−60 nm were synthesized using emulsion polymerization. Emulsifier-free synthesis was also employed, yielding particles in the size range of 80−90 nm. Sodium styrene sulfonate (NaSS) was used an emulsifying comonomer, and divinyl benzene (DVB) was used as a cross-linking agent. The average particle diameter increased with increasing DVB concentration in the feed. …
Control Of Polystyrene Film Dewetting Through Sulfonation And Metal Complexation, Yi Feng, Alamgir Karim, Robert Weiss, Jack F. Douglas, Charles C. Han
Control Of Polystyrene Film Dewetting Through Sulfonation And Metal Complexation, Yi Feng, Alamgir Karim, Robert Weiss, Jack F. Douglas, Charles C. Han
Robert Weiss
The dewetting of low molecular weight sulfonated polystyrene ionomers (SPS) on inorganic silicon oxide substrates is compared with unmodified polystyrene (PS, Mw = 4000) using a combination of X-ray reflectivity, optical and atomic force microscopy. The amounts of sulfonate group and metal counterion (Li+, Zn2+) were both varied in our study. Unlike unmodified PS, which readily dewets the substrate, a strong inhibition of dewetting occurs for low sulfonation (2.3 mol %), and no apparent dewetting was found for high sulfonation (≥7 mol %). For ZnSPS, dewetting was not observed in any of the films, even for those with very low …
Compatibilization Of Polymer Blends By Complexation: 3. Structure Pinning During Phase Separation Of Ionomer/Polyamide Blends, Yi Feng, Robert Weiss, C. C. Han
Compatibilization Of Polymer Blends By Complexation: 3. Structure Pinning During Phase Separation Of Ionomer/Polyamide Blends, Yi Feng, Robert Weiss, C. C. Han
Robert Weiss
The effects of strong intermolecular interactions on the phase behavior and phase separation kinetics of an ionomer/polyamide blend were investigated by light scattering and optical microscopy. The lithium salt of lightly sulfonated polystyrene (Li-SPS) ionomers (4.0−9.5 mol % sulfonation) and poly(N,N‘-dimethylethylene sebacamide) (mPA) are miscible as a result of the formation of an ion−amide complex. The blends exhibit LCST-type phase behavior. Phase separation can be thermally induced and is thermodynamically reversible. The phase separation process stalls after a couple of hours due to structure pinning, which may be due to concentration of the ion−amide complexes in a ionomer-rich phase and/or …