Copolymer Research Articles

In vitro microbicidal activity of W/O/W multiple emulsion for vaginal administration

The microbicidal activity of a W/O/W multiple emulsion destined for vaginal application, containing lactic acid in the internal aqueous phase, octadecylamine (ODA) in the oily phase and benzalkonium chloride (CBZ) in the external aqueous phase was evaluated against three microbial strains: Escherichia coli, Staphylococcus aureus and Candida albicans. The results were different depending on the procedure used. Interpretable results were obtained if only a gentle agitation was used just after the introduction of the microbial suspension to the product. This suggested that vigorous agitation lead to a variable fraction of CBZ or ODA entrapped in the micelles of ethylene and propylene oxide copolymer (COE).

Doping states of xPPP/yPA diblock copolymers

A tight-binding model describing the xPPP/yPA diblock copolymer has been adopted. The ground states, doping states, configurations, electronic distributions and the types of excitations have been studied. It is found that the ratios and interfacial couplings of the components have effect on the properties of excitations in xPPP/yPA diblock copolymers. The interface between two homopolymers acts as an energy barrier which increases with the weakening of the interfacial coupling.

Immunogenic Cu2+-induced biopolymer systems comprising a steroid hormone, protein antigen, and synthetic polyelectrolytes.

We have synthesized the 17beta-estradiol comprising polycomplexes by the Cu(2+)-mediated complex formation of polyanionic polyelectrolyte (PE), [polyacrylic acid (PAA), nontoxic copolymers (CP) of acrylic acid with N-isopropylacrylamide and N-vinylpyrolidine] with BSA-estradiol covalent conjugates at the relatively low concentrations of metal ions in neutral water. Cu(2+) ions in the composition of biopolymer systems act as "fasteners" between macromolecules of same (negatively) charged polyanionic PE with protein carrier, promoting the formation of relatively stable polycomplex particles in physiological conditions. These hapten- and protein comprising Biopolymer Systems possess simultaneously highly estradiol and BSA-specific immunogenicity without traditional adjuvants after a single intravenous immunization of mice. The obtained results are of interest for the construction of polydeterminant immunogen and vaccines based on polymer derivatives of steroid hormones.

Patterning of Hyperbranched Polymer Films

This Review describes new methods for patterning functional hyperbranched poly(acrylic acid) thin polymer films. “Hyperbranched polymer” is a generic term used to describe a wide variety of polymeric materials that contain a high percentage of functional groups, that are highly branched, and that are irregular in structure. Hyperbranched polymer films (HPFs) are prepared by an iterative three-step process: activation of an acid functionalized surface, surface grafting of amine-terminated poly(tert-butyl acrylate), and hydrolysis to regenerate the acid surface. The resulting materials have a high density of acid groups, which can be functionalized with moieties that introduce interesting optical, electrochemical, biological, and mechanical properties to the films. HPFs can be patterned with micron-scale resolution using either a template-based approach or photolithography. Templates consist of self-assembled monolayers prepared by microcontact printing, whereas photolithographic patterning relies on selective hydrolysis using photoacids. Biocompatibility can be introduced by grafting a conformal layer of poly(ethylene glycol) atop the HPFs. Such patterns serve as templates for spatially segregating viable mammalian and bacterial cells. In addition to the PAA HPFs, another family of patternable HPFs consisting of dendrimers and an active anhydride copolymer is described.

Pressure Studies on the Metallation of Porphyrin-Carrying Copolymers

Pressure Studies on the Metallation of Porphyrin-Carrying Copolymers

Calculation of the [n] (M) relationship for ethylene/propylene copolymers from the relations for homopolymers

Calculation of the [n] (M) relationship for ethylene/propylene copolymers from the relations for homopolymers

Influence of solvent and polymer sort on anomalous rheological behavior of polymer solution at high dilution

The rheological behavior of polyvinyl acetate (PVAc) in N,N′=dimethylformamide (DMF), methyl ethyl ketone (MEK), 1,2-dichloroethane (DCE), tetrahydrofuran (THF) and toluene (TOL), polystyrene (PS) in DMF, MEK, DCE, THF and cyclohexane (CYH), and random ethylene-vinyl acetate (EVA) copolymer in DCE, TOL, CYH with and without surfactant of Span80 and in the DCE/CYH solvent mixtures with surfactant of Span80 was examined at high dilution. It was shown that the extent and type of the upsweep or downsweep (anomalous rheological behavior) of the reduced viscosity-concentration curves of these different polymers at high dilution are markedly dependent on the dielectric constant of the solvent and the polarity of the polymer used. The experimental results indicated that the anomalous rheological behavior of EVA copolymer, widely used as a flow improver, is related to its efficiency in reducing viscosity and depressing pour point of crude oil and waxy solvents.

Hyperbranched copolymers made from A2, B2 and BB′2type monomers (iv)

Hyperbranched copolymers made from A2, B2 and BB′2type monomers (iv)

A water‐soluble self‐doped conducting polypyrrole‐based copolymer

A water-soluble self-doped conducting polypyrrole-based copolymer was synthesized via the grafting of pyrrole onto the p-aminodiphenylamine moieties of a water-soluble copolymer. The conductive copolymer exhibited a conductivity as large as 3.4 S/cm. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 86–89, 2001

New materials by polymerization of olefins and styrene by metallocene/mao catalysts

Metallocenes and other transition metal compounds comprise a new generation of single site catalysts for the production of precisely designed polyolefins and engineering plastics. The discovery of metallocene methylalumoxane (MAO) catalysts has opened a frontier in the area of polymer synthesis and processing. A great number of symmetric and chiral zirconocenes have been synthesized to give isotactic, syndiotatic, isoblock, or stereoblock polymers with increased impact strength and toughness, better melt characteristics or elasticity, and improved clarity in films. Cycloolefin copolymers (COC) and syndiotactic polystyrene can be produced by metallocene catalysts. These are new types of polymers with special properties and a high potential as engineering plastics. Norbornene-ethene copolymers are most interesting for technical uses because of the easily available monomers. Due to different incorporation values of the cyclic olefin in the copolymer, the glass transition temperature can vary over a wide range and reaches 180°C.

Aspects of Phosphazene Research

This review reports research carried out by the authors during the last 10 years. The research involves the synthesis, characterization, functionalization, and possible utilization of cyclo- and polyphosphazenes. The investigations concern the synthesis of poly(dichlorophosphazene) by polycondensation reaction of dichlorophinoyliminotrichlorophosphorane; the grafting of unsaturated organic substrates (maleic anhydride, maleates or vinyl polymers) onto poly(organophosphazenes) by free radical reactions and the use of the synthesized materials for the preparation of new grafted copolymers or for the superficial modification of conventional organic macromolecules; the synthesis of phosphazenes containing free hydroxylic groups by reaction of methoxy aryloxy- or methoxy oligoethyleneoxy-substituted cyclo- and polyphosphazenes with boron tribromide or trimethylsilyl iodide and their use for the preparation of new phosphazene-based materials (e.g., sol-gel hybrids, thermosetting resins, azodyes, cyclolinear inorganic–organic polymers sometimes containing chiral units, or organic macromolecules having cyclophosphazene residues as pendant groups); and the preparation of oxazoline-containing cyclic and polymeric phosphazene derivatives for the synthesis of photoinitiators, chain extenders, or blend compatibilizers. The possible developments of this research are also envisaged.

Curing kinetics of epoxy-urethane copolymers

Fil: Stefani, Pablo Marcelo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnologia de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingenieria. Instituto de Investigaciones en Ciencia y Tecnologia de Materiales; Argentina

Studies on the microstructure of vinyl/N‐phenylmaleimide copolymers by NMR and their applications

Studies on the microstructure of vinyl/N‐phenylmaleimide copolymers by NMR and their applications

Highly Efficient Monocationic Palladacycles of Chelating Diphosphines in C2H4/CO Copolymerization

Cationic palladacycles of the general formula [{o-C6H4(CH2)N(R)2Pd(P⌒P)}][X] (P⌒P = Ph2P(CH2)3PPh2, (PhCH2)2C(CH2PPh2)2; X = Cl, PF6, B(C6H5)4; R = H, CH3, CH2C6H5) and [{o-(CH2)C6H4P(o-Tol)2Pd(P⌒P...

Acrylamide and Butyl Acrylate Polymerization in Winsor IV (w/o) and Winsor I (o/w) Microemulsions

The preparation of toluene-based single-phase Winsor IV water-in-oil (w/o) inverse microemulsions containing the (co)monomer couple acrylamide (AAm)/butyl acrylate (BA), their transformation to the two-phase Winsor I (oil-in-water (o/w) microemulsion phase + excess of oil phase) microemulsion and homo- and (co)polymerization of (co)monomers initiated by ammonium peroxodisulfate in both types of microemulsions were studied. Increasing of the volume fraction of aqueous phase, Φaw, of the parent single-phase Winsor IV w/o inverse microemulsion by addition of solution of AAm in water led first only to the increase of AAm monomer concentration in inverse microemulsion, and finally to the formation of a two-phase Winsor I o/w microemulsion. Thus, Winsor IV and Winsor I microemulsions characterized with 3-fold and 6-fold higher content of AAm (i.e., up to 6 mass % in Winsor IV and 12 mass % in the microemulsion phase of Winsor I with respect to only 2 mass % in the parent Winsor IV w/o microemulsion) were obtain...

Carbosilane/carbosiloxane-based ADMET homopolymers and copolymers possessing latent reactivity

Carbosilane/carbosiloxane-based ADMET homopolymers and copolymers possessing latent reactivity

Opracowanie metody syntezy wloknotworczego kopolimeru zelatyna-g-poliakrylonitryl

Opracowanie metody syntezy wloknotworczego kopolimeru zelatyna-g-poliakrylonitryl

Photochemical degradation of poly(ethylene terephthalate)-modified copolymer

The photolysis and the photooxidation of poly(ethylene terephthalate, PET)-modified copolymer have been investigated. The copolymer (COP) that results from the polycondensation of terephthalic acid, ethyleneglycol and 1,4-cyclohexanedimethanol was studied and a comparison with the behaviour of PET was made. Under vacuum irradiation at λ>300 nm, the pure photolytic processes involve Norrish type I and II reactions. The formation of the hydroxylated and carbonyl containing photolytic products, which involves hydrogen abstraction from the polymeric backbone, is enhanced in the COP: this result is related to the labile hydrogen atom on the tertiary carbon atom of the cyclohexane units. The pure photolytic processes, in the presence of oxygen, induces oxidation of the aliphatic sequences under polychromatic (λ>300 nm) and monochromatic irradiations (254 and 365 nm). The tertiary carbon atoms of the cyclohexane units are shown to be more oxidizable than the methylene groups in the α-position of the ester groups. The decomposition of the hydroperoxides so formed leads to the formation of acetic and formic acids that can migrate out of the film; it also generates hydroxy radicals that is one path leading to the ortho-hydroxylation of aromatic rings which gives fluorescence emission to the photooxidised films. The penetration of polychromatic light in the COP sample limits the degradation to the 100 μm top layer. In this superficial layer, chain scission occurs to a large extent as revealed by the identification of terephthalic acid.

Synthesis and Properties of a “Protein-Like” Copolymer

Synthesis and Properties of a “Protein-Like” Copolymer

Characterization of a New Poly(acrylonitrile-itaconate) based Gel-electrolyte

A new gel polymer electrolyte based on the modified polyacrylonitrile (PAN), polyacrylonitrile-co-bis[2-(2-methoxyethoxy)ethyl]itaconate (abbreviated as PANI) copolymer was synthesized in expectation of enhanced trapping ability of liquid electrolytes. PAN and PANI blend was complexed with organic solvents, ethylene carbonate (EC) and dimethyl carbonate (DMC), and salt. The highest room temperature conductivity of was found for a film of 25PAN+10PANl+50EC/DMC+. The solvent-rich crystalline part decreases due to the blending of PANI and therefore number of charge carriers increases giving higher ionic conductivity. The addition of PAM as a host polymer in the PAN-based gels has beneficial effects such as higher ionic conductivity, better thermal characteristics, better miscibility with solvent, wider electrochemical stability, and better interfacial stability with lithium electrode, though it exhibits slightly less mechanical rigidity.