Showing papers on "Copolymer published in 1978"

Polysiloxane composition and contact lens

Abstract: Monomeric polysiloxanes end-capped with activated unsaturated groups and polymers and copolymers thereof are disclosed herein for use as contact lenses with improved properties, such as, oxygen transportability, hydrolytic stability, biological inertness, transparency and improved strength without the use of fillers. The polymer composition comprises a poly(organosiloxane) α, ω terminally bonded through a divalent hydrocarbon group to a polymerized activated unsaturated group. Contact lenses made therefrom can be, as commonly referred to, "hard" or "soft". This hardness or softness is a function of the comonomer or the molecular weight of the monomers. Preferable the contact lenses are "soft". The copolymer compositions of the instant invention comprise the polymerization product of the polysiloxane monomers and monomer or monomers containing an activated vinyl group. These polymers are employed to make optical products, e.g. contact lenses, intraocular implants, etc.

A Novel Type of Polycondensation Utilizing Transition Metal-Catalyzed C–C Coupling. I. Preparation of Thermostable Polyphenylene Type Polymers

Abstract: Transition metal compounds including NiCl2(bpy) (bpy=2,2′-bipyridine), NiBr2(PPh3)2 (PPh3=triphenylphosphine), PdCl2(bpy), NiCl2, CoCl2, FeCl2, and FeCl3 catalyze polycondensation of di- and polyhalogenated organic aromatic compounds by dehalogenation with magnesium under mild conditions. Poly(p-phenylene), poly(m-phenylene), poly(oxybiphenylene), and poly(phenylenemethylene) were prepared from p-dihalobenzene, m-dichlorobenzene, bis(p-bromophenyl) ether, and α,p-dichlorotoluene. They have a high degree of polymerization and high thermal stability. Poly(p-phenylene), poly(oxybiphenylene), and poly(phenylenemethylene) have regularly repeated structures as proved by IR spectroscopy and X-ray powder diffraction. Polymerization of polyhalogenated aromatic compounds (1,3,5-trichlorobenzene and hexachlorobiphenyl) in tetrahydrofuran (THF) gave copolymers having aromatic nuclei and THF units. Polymerization of the haloaromatic compounds is considered to proceed through a mechanism in which consecutive cycles of ...

Addition copolymers of lactide and glycolide and method of preparation

Abstract: Relatively high molecular weight, fiber-forming, crystalline copolymers of lactide and glycolide are prepared in a two-stage polymerization process. In the first stage there is prepared a random copolymer of a major proportion of an optically active lactide with a minor proportion of glycolide or d,l-lactide. In the second stage, a major amount of glycolide and a minor amount of lactide monomers are admixed with the copolymer of the first stage and the polymerization resumed until there is obtained a high molecular weight addition copolymer of lactide and glycolide containing from about 50 to 75 wt percent of units derived from glycolide. The polymer is fiber-forming and useful in the preparation of absorbable surgical sutures.

Polysiloxane shaped article for use in biomedical applications

Abstract: Monomeric polysiloxanes end-capped with activated unsaturated groups and polymers and copolymers thereof are disclosed herein for use as contact lenses and biomedical devices with improved properties, such as, oxygen transportability, hydrolytic stability, biological inertness, transparency and improved strength without the use of fillers. The polymer composition comprises a poly(organosiloxane) monomer α,ω terminally bonded through divalent hydrocarbon groups to polymerized free radical polymerizably activated unsaturated groups. Contact lenses and biomedical devices i.e. shaped article for use in biomedical applications made therefrom can be "hard" or "soft". This hardness or softness is a function of the comonomer or the molecular weight of the monomers. Preferably the contact lenses and biomedical devices are "soft". The copolymer compositions of the instant invention comprise the polymerization product of the polysiloxane monomers and monomer or monomers containing an activated vinyl group. These polymers are employed to make biomedical devices and optical products, e.g. contact lenses, intraocular implants, etc.

Water-insoluble hydrophilic copolymers

Abstract: A water-insoluble hydrophilic gel comprising: (A) about 30 to about 90% of a hydrophilic (a) polymer of identical or different water-soluble mono-olefinic monomers, or (b) copolymer of said water-soluble monomers with 1 to 70% of water-insoluble, identical or different mono-olefinic monomers, which polymer or copolymer is cross-linked with (B) about 10 to about 70% of a terminal diolefinic hydrophobic macromer having a molecular weight from about 400 to about 8000.

Electrochromic devices with polymeric electrolytes

Abstract: Improved electrochromic devices result from the incorporation of novel polymeric electrolytes. The electrolytes are based upon copolymers prepared from vinyl monomers and acid-group-containing monomers.

Methylene Sequence Distributions and Number Average Sequence Lengths in Ethylene-Propylene Copolymers

Abstract: (57) ABSTRACT A non-sealable, multi-layer polypropylene film which includes a base layer of polypropylene and at least one cover layer. The cover layer includes a propylene-ethy lene copolymer which includes about 1.2 to 2.8% by weight of ethylene and has a distribution factor VF greater than about 10, an enthalpy of fusion AH greater than about 90J/g and a melt index of about 3 to 12 g/10 min. under a load of 21.6N and about 230 C. The film is particularly useful in laminating and as a support film for aqueous coating systems.

Thermal polymerization of styrene

Abstract: An experimental investigation of the kinetics of bulk thermal polymerization of styrene in the temperature range of 200°–230°C is reported. Conversions and molecular weight averages were measured by gel permeation chromatography. At elevated temperatures, oxygen in the polymerization mixture appears to have negligible effect on the rate of polymerization and the molecular weights of the polymer. Experimental evidence suggests that the molecular weight development of the polymer is strongly influenced by transfer reactions.

The influence of hydrophilic and hydrophobic domains on water wettability of 2-hydroxyethyl methacrylate-styrene copolymers

Abstract: Cooligomers and ABA-type block copolymers composed of a hydrophilic monomer, 2-hydroxyethyl methacrylate (HEMA), and a hydrophobic monomer, styrene, were synthesized to study the relation between their microstructure and hydrophilic and hydrophobic functions. Films of cooligomers and ABA-type block copolymers were cast from DMF solutions at 40°C. The wettability, which was determined from the contact angle with water, increased considerably when HEMA mole fraction reached around 0.8 in the cooligomer system and around 0.9 in the ABA-type block copolymer system. The microstructures of the copolymer films were observed by electron microscopy using the osmium tetroxide fixation technique. The morphologic change in the domain structure was observed at an HEMA mole fraction of about 0.8 in the cooligomer system and about 0.9 in the ABA-type block copolymer system. It is suggested that hydrophilic and hydrophobic functions are largely influenced by the state of aggregation of each segment, that is, the size and geometry of the hydrophilic and hydrophobic domains.

Water-insoluble hydrophilic copolymers used as carriers for medicaments and pesticides

Abstract: A water-insoluble hydrophilic gel comprising: (A) about 30 to about 90% of a hydrophilic (a) polymer of identical or different water-soluble mono-olefinic monomers, or (b) copolymer of said water-soluble monomers with 1 to 70% of water-insoluble, identical or different mono-olefinic monomers, which polymer or copolymer is cross-linked with (B) about 10 to about 70% of a terminal diolefinic hydrophobic macromer having a molecular weight from about 400 to about 8000.

Interaction between Plasma Protein and Microphase Separated Structure of Copolymers

Abstract: Bovine serum albumin and γ-globulin were adsorbed, respectively, on films of ABA-type block copolymers and blendmers composed of 2-hydroxyethyl methacrylate (HEMA) and styrene in a mixture of protein and 0.2 M of phosphate buffer solution (pH 7.4) under the condition of 1/50 physiological concentration of the protein at 37°C. The morphologies and dimensions of the microphase separated structure of the block copolymers and blendmers containing hydrophilic domains of HEMA molecules and hydrophobic domains of styrene molecules were studied by electron microscopy with or without osmium tetroxide fixation. In the adsorption of plasma protein, either both the adsorbed plasma protein and the hydrophilic domains or only the adsorbed plasma proteins could be stained selectively with osmium tetroxide to control the fixation time. Therefore the areas of plasma protein adsorbed on the phase of microseparated structure were evaluated by comparing the micrographs with and without the adsorbed plasma proteins. These results show that bovine serum albumin is adsorbed on the hydrophilic domains escaping from the hydrophobic domains, and on the contrary that γ-globulin is selectively adsorbed on the hydrophobic domains.

Estimation of monomer reactivity ratios by nonlinear least-squares procedure with consideration of the weight of experimental data

Abstract: To obtain the optimum values of the monomer reactivity ratios for the copolymerization systems with largely different reactivities between both monomers, a nonlinear least-squares procedure which took into account the weights of experimental data, was proposed and discussed. The weights of the data were treated for the errors arisen from the amounts of monomers charged, the densities of monomers, the weights of copolymer formed, and the composition of copolymer. The least-squares procedure with the consideration of the weights was applicable to both differentiated equation and integrated equation derived by Lewis and Mayo. This procedure was applied to radical copolymerizations of α-substituted crotonic esters with styrene, and reasonable monomer reactivity ratios were obtained. It was noted that errors from the copolymer composition were more important than those from the other factors and that the use of the integrated equation was recommended even when the copolymers were isolated at low conversions.

Structural Change Accompanied by Plastic-to-Rubber Transition of SBS Block Copolymers

Abstract: It was shown that some block copolymers and their blends with corresponding homopolymers exhibit stress softening. When the specimens are stretched beyond the yield point, they become rubbery and exhibit high elasticity and large recoverable deformation, as a result of a breakup of their original rigid structure. Moreover, the deformed specimens heal, in that the properties of the original undeformed specimens are recovered upon removal of applied stress. This effect was attributed to the reformation of the original microdomain structure. In this work, we investigated an SBS block copolymer and a blend of the copolymer with homopolystyrene in regard to the structural change accompaning the plastic-to-rubber transition and the healing process. Electron microscopy and small angle X-ray scattering (SAXS) were used.

Butadiene/acrylonitrile photosensitive, elastomeric polymer compositions for flexographic printing plates

Abstract: Photosensitive, elastomeric compositions containing (1) a high molecular weight butadiene/acrylonitrile copolymer, (2) a low molecular weight butadiene polymer, (3) an ethylenically unsaturated monomer, and (4) a free-radical generating system have outstanding properties as photosensitive coatings for flexographic printing plates. When the combination of high and low molecular weight polymers contains at least about 2% by weight of carboxyl groups, the compositions are processable in aqueous or semiaqueous basic solutions.

Heat sealable resin blends

Abstract: A resin blend for producing a peelable heat seal, which does not produce "angel hair" upon separation, includes polybutylene and a copolymer of ethylene with, for example, vinylacetate or methyl acrylate. Typical substrates are high density polyethylene and nylon.

Fluorinated ion exchange polymer containing carboxylic groups, process for making same, and film and membrane thereof

Abstract: Fluorinated ion exchange polymers which have pendant side chains which contain --OCF2 COOR groups, or which have both pendant side chains containing carboxylic groups and pendant side chains which contain sulfonyl groups, when used in the form of membranes to separate the anode and cathode compartments of an electrolysis cell, permit operation at high current efficiency. Those containing both carboxylic and sulfonyl groups can be made by oxidation of fluorinated polymers which have pendant side chains containing sulfinic groups, or both sulfinic and sulfonyl groups. The fluorinated polymers which have pendant side chains containing sulfinic groups, or both sulfinic and sulfonyl groups, are in turn made from fluorinated polymers which have pendant side chains containing sulfonyl halide groups by reduction with, for example, hydrazine. Those polymers which have only pendant side chains which contain --OCF2 COOR groups can be made by copolymerization of a mixture of monomers, one of which is a vinyl monomer which contains the indicated carboxylic group. Fluorinated ion exchange polymers which have pendant side chains containing --OCF2 COOR groups and also pendant side chains which contain sulfonyl groups can also be made by copolymerization of a mixture of monomers, one of which is a vinyl monomer which contains the indicated carboxylic group; and also by treatment of a polymer which contains --OCF2 CF2 SO3 H or salts thereof with a combination of fluorine and oxygen.

Prevention of fouling in polymerization reactors

Abstract: An olefin or mixture of olefins is polymerized in a hydrocarbon diluent in a turbulent reaction zone to produce particles of polymer which are substantially insoluble in the diluent (particle form process). Fouling of the reactor by adherence of polymer particles to the walls of the reactor is reduced by adding to the reaction medium a composition which comprises a mixture of (a) a polysulfone copolymer, (b) a polymeric polyamine, and (c) an oil-soluble sulfonic acid.

Thermal analysis of styrene–alkyl methacrylate polymers. II. Thermogravimetric kinetics

Abstract: The thermal stability and degradation kinetics of several polystyrenes and styrene–alkyl methacrylate copolymers and terpolymers with a number-average molecular weight (Mn) of 6000–250,000 g/mole have been studied using dynamic thermogravimetry (TG). The degradation kinetics of each polymer sample have been successfully attributed to a sample first-order reaction expression. The results indicate that the thermal stability and degradation kinetics of the polymers are independent of the size of the molecules within the molecular weight range investigated. The steric hindrance effects of the pendent groups appear to be responsible for the improved thermal stability and resistance of CC bond scission in the styrene–alkyl methacrylate copolymers and terpolymers.

Intramolecular excimer formation in macromolecules. I. Energy migration and excimer formation in copolymers exhibiting nearest‐neighbor excimer interactions

Abstract: Energy migration and intramolecular excimer formation have been studied in a series of copolymers comprising 1-vinylnaphthalene, 2-vinylnaphthalene, and styrene with methyl methacrylate. The technique of fluorescence depolarization was used to characterize energy migration in glassy solutions of the copolymers. The extent of energy migration in these copolymers is determined by the mean sequence length of aromatic species la. Assuming that excimer formation occurs as a result of nearest-neighbor interactions, the concentration of excimer sites in the macromolecule will be proportional to the fraction of links between aromatic species faa. It is proposed that these sites are populated via energy migration from the site of absorption. Proportionality between the ratio of excimer to monomer emission intensities and the function la·faa was predicted. Good agreement with this relationship was obtained in each of the copolymer systems studied. Reactivity ratios of methyl methacrylate (rm) in copolymerization at 70°C with the aromatic monomers (ra) were determined as: 1-vinylnaphthalene—rm = 0.43, ra = 1.71: 2-vinylnaphthalene—rm = 0.37, ra = 4.46; styrene-rm = 0.45, ra = 0.58.

Thermoplastic polyurethane blends containing a processing aid

Abstract: The instant invention is directed to novel thermoplastic polyurethane materials containing a processing aid. More particularly, the instant invention is directed to a thermoplastic polyurethane composition comprising: (A) from 40 to 100 percent by weight of a thermoplastic polyurethane, (B) from 0 to 60 percent by weight of a thermoplastic polymer selected from the group consisting of thermoplastic polycarbonates, thermoplastic polyoxymethylenes, thermoplastic acrylonitrile/butadiene/styrene graft copolymers, thermoplastic polybutylene terephthalates, thermoplastic polyethylene terephthalates, and mixtures thereof and (C) from 0.5 to 10 percent by weight based on the amount of (A) and (B), of a processing aid which is an acrylic polymer having a number average molecular weight of from 500,000 to 1,500,000. The acrylic polymers are preferably selected from the group consisting of homopolymers of methyl methacrylate and n-butyl methacrylate, copolymers of methyl methacrylate and ethyl acrylate and terpolymers of methyl methacrylate, n-butyl acrylate and styrene, said homopolymers, copolymers and terpolymers having number average molecular weights of from 500,000 to 1,500,000.

Model compounds and 13C NMR investigation of isolated ethylene units in ethylene/propene copolymers

Abstract: The stereochemical environment of the isolated ethylene units, and the arrangement of the neighbouring propylene units, in ethylene/propene copolymers, prepared in the presence of syndiotactic-specific and isotactic-specific catalysts are investigated by comparing 13C NMR spectra of selectively 13C-enriched copolymers and suitable model compounds. The implications of copolymer structure on polymerization mechanism are considered. In the presence of homogeneous syndiotactic specific catalyst systems both the regiospecificity and the stereospecificity are controlled by the last unit of the growing chain end. Regiospecificity and stereospecificity are unaffected by the ethylene units in the isotactic polymerization.

Flexible heat-shrinkable multilayer film for packaging primal meat

Abstract: A heat-shrinkable multilayer film suitable for use in the packaging of primal meat cut, includes a first outer layer comprising a blend of a propylene-ethylene copolymer, a (butene-1)-ethylene copolymer, and a thermoplastic elastomer selected from the group consisting of ethylene-propylene copolymers and ethylene-propylene diene terpolymers; a first core layer connected to the first outer layer and being capable of being stretched during the biaxial orientation of the multilayer film and comprising an extrudable adhesive; a second core layer connected to the first core layer and serving as an oxygen barrier to protect the meat cut from spoilage and being compatible to the biaxial orienting and heat shrinking of the film; and a second outer layer comprising an ethylene vinyl acetate copolymer; the multilayer film being biaxially oriented

Photographic element in which the antistatic layer is interlinked in the base

Abstract: An antistatic composition for photographic films which can withstand wet processing is formed by reacting (1) a hydrophobic polymer containing carboxyl groups, (2) a water-soluble copolymer of the sodium salt of styrene sulfonic acid and a carboxyl-containing monomer and (3) carboxylic groups on the film surface to be protected, with (4) a water-soluble polyfunctional aziridine crosslinking agent.

Olefin polymer blends and films therefrom

Abstract: A heat-shrinkable multilayer film suitable for use in the packaging of a frozen poultry, includes a first outer layer comprising a blend of a propylene-ethylene copolymer having a high isotactic molecular structure with less than about 6% by weight ethylene and having a melt flow of from about 1.5 to about 18 decigrams per minute; a (butene-1)-ethylene copolymer having a high isotactic molecular structure with less than about 10% by weight being ethylene and having a melt flow of from about 0.1 to about 5.0 decigrams per minute, and a thermoplastic elastomer selected from the group consisting of ethylene-propylene copolymers and ethylene-propylene diene terpolymers, the ratio by weight of the propylene-ethylene copolymer to the (butene-1)-ethylene copolymer being from about 2:1 to about 1:2 and the thermoplastic elastomer being present from about 10% to about 50% by weight; at least one core layer capable of being biaxially oriented and heat shrinkable and comprising an extrudable adhesive; and a second outer layer comprising a polymer selected from the group consisting of ethylene homopolymers and copolymers each having a highly branched molecular structure; the multilayer film being biaxially oriented.