Showing papers on "Copolymer published in 1974"

Recent advances in polymer blends, grafts, and blocks

Abstract: Section I. Introduction.- An Introduction to the Synthesis of Block- and Graft Copolymers.- Practical Properties of Multi-Phase Polymer Systems.- On the Generation of Novel Polymer Blend, Graft, and IPN Structures through the Application of Group Theory Concepts.- Effects of Monomer Unit Arrangement on the Properties of Copolymers.- Block Copolymer Theory. II. Statistical Thermodynamics of the Microphases.- Cationic Grafting: The Synthesis and Characterization of Butyl Rubber-g-Polystyrene and PVC-g-Polyisobutylene.- Synthesis, Morphology, and Properties of AB Crosslinked Copolymers.- Section II. Introduction.- Polysulfone-Nylon 6 Block Copolymers and Alloys.- Dynamic Mechanical Properties of Urea-Urethane Block Polymers.- Orientation Studies of Polyurethane Block Polymers.- Butadiene-Styrene AB Type Block Copolymers.- New Developments in Block Copolymer Applications.- Polystyrene-Poly (?-Methyl Styrene) AB Block Copolymers and Alloys.- Section III. Introduction.- The Synthesis, Characterization and Physical Properties of EPM-g-Polystyrene Thermoplastic Elastomers.- The Causes of Pitting and Haze on Molded ABS Plastic Surfaces.- Poly(Butadiene-Co-Styrene)/Polystyrene IPN's, Semi-IPN's and Graft Copolymers: Staining Behavior and Morphology.- Topologically Interpenetrating Polymer Networks.- Time-Temperature Superposition in Two-Phase Polyblends.- Contributors.

The influence of carbon black on the extrusion characteristics and rheological properties of elastomers: Polybutadiene and butadiene–styrene copolymer

Abstract: An experimental study of the influence of carbon black loading, particle size, and structure on the extrusion characteristics of polybutadiene and butadiene–styrene copolymer synthetic rubber is described. The development of extrudate distortion and its mechanisms are considered. The viscosity and die swell have been related to black loading, particle size, and structure. Generally, it is found that black surface area and structure acts to increase viscosity and decrease elastic memory. This situation is analyzed in terms of the theory of nonlinear viscoelasticity. Two mechanistic theories are described which may explain this behavior. One theory is based on the continuum mechanics analysis of suspensions of particles in viscoelastic media. The rheological behavior of the black compounds is explained in terms of the increased severity of deformation in the polymer matrix surrounding the particle agglomerates. The second theory is based on the view of an entanglement network containing black particles. Polymer chains may be adsorbed onto the surface giving rise to increased entanglement densities.

Trifluorostyrene sulfonic acid membranes

Abstract: This disclosure is directed to fluorocarbon polymers, polymeric membranes, and electrochemical cells and processes. The polymers and membranes are produced by radiation techniques to provide improved products. For example, α,β,β-trifluorostyrene in an inert organic solvent is grafted onto an inert film, such as tetrafluoroethylene-hexafluoropropylene copolymer, by irradiation, i.e. with Co-60 gamma radiation at a dose of several Mrad. The grafted film is then sulfonated, preferably in a chlorosulfonic acid bath. The resulting film is useful as a membrane or diaphragm in various electrochemical cells such as chlor-alkali or fuel cells.

Acrylate-styrene-acrylonitrile composition and method of making the same

Abstract: An impact-resistant and weatherable thermoplastic composition comprising from about 10 to about 50 weight percent of a crosslinked acrylate elastomer having a Tg of less than 25°C., from about 5 to about 35 weight percent of a crosslinked styrene-acrylonitrile copolymer and from about 15 to about 85 weight percent of a non-crosslinked or linear styrene-acrylonitrile copolymer. The composition is made by a three-step sequence comprising emulsion polymerizing of an alkyl acrylate containing at least one crosslinking monomer, emulsion polymerizing a monomer mixture of styrene, acrylonitrile and at least one crosslinking monomer in the presence of the crosslinked acrylate elastomer formed in the previous step, or a reverse sequence of the prior two emulsion polymerization procedures, and, finally, emulsion or suspension polymerizing of styrene, acrylonitrile in the presence of the previously formed product.

Molded structures containing crystalling polyolefin saponified ethylene vinyl acetate copolymer and carbonyl containing copolymers

Abstract: A resinous composition excellent in processability and gas permeation resistance, which comprises (A) 30 to 98 % by weight of a crystalline polyolefin, (B) 2 to 70 % by weight of a saponified product of an ethylene-vinyl acetate copolymer having an ethylene content of 25 to 75 mole % and a degree of saponification of at least 93 %, and (C) 0.5 to 15 parts by weight, per 100 parts by weight of said polyolefin and ethylene-vinyl acetate copolymer saponified product, of a thermoplastic polymer containing a carbonyl group in the main or side chain thereof, and a molded structure formed therefrom, which has a specific multi-layer structure and a high gas permeation resistance.

Low temperature process for the preparation of graft copolymer dispersions

Abstract: Graft copolymer dispersions of improved viscosity and superior particle size distribution are prepared by the in situ polymerization of vinyl monomers in unsaturation-containing polyols in the presence of a free-radical catalyst and certain chain transferring agents at temperatures below 100° C. The dispersions are low viscous liquids which may be advantageously employed in the preparation of polyurethanes.

Synthesis and characterization of polymers with pendent phosphonate groups

Abstract: Soluble chloromethylated polystyrene and its copolymers with vinylidene chloride as well as poly(phenyl oxides) brominated in the side chains and in the ring were synthesized and characterized in detail by NMR. The halogenated polymers were phosphonylated with alkyl phosphites. Uncrosslinked polymers with pendent phosphonate groups were prepared in the presence of etheral solvents, which solvate the ionic intermediates of the Arbuzov reaction. These polyphosphonates are highly hygroscopic and are soluble in a variety of solvents. Their Tg's are in the range of 50–175°C. Their thermal behavior was analyzed on the basis of thermogravimetric measurements combined with mass-spectrometric analysis. Poly(styrene phosphonate) seems to be the most stable, and its thermal decomposition starts at ∼330°C. The polymeric phosphonates are compatible with an unusually large number of polymeric systems and seem to form “true” polymeric alloys with acetylcellulose.

Phenolic resins for solid‐phase peptide synthesis: Copolymerization of styrene and p‐acetoxystyrene

Abstract: Details are given of the synthesis and purification of p-acetoxystyrene and its solution and suspension copolymerization with styrene. Reactivity ratios, evaluated by the Tidwell-Mortimer method, were r1 (p-acetoxystyrene) = 1.18, and r2 (styrene) = 0.88 for (bulk) solution copolymerization. Corresponding values of the reactivity ratios for suspension copolymerization were, within experimental error, indistinguishable from unity. Thus the copolymer composition is governed simply by the monomer feed composition. Use of a specially designed reactor vessel permits convenient suspension copolymerization of styrene, p-acetoxystyrene, and divinylbenzene to give crosslinked resins having comparatively narrow particle size distributions. Acetoxy groups in the crosslinked resin are cleaved by hydrazine hydrate under very mild conditions to give crosslinked polystyrenes having phenolic groups which, in turn, provide a useful alternative to the more usual chloromethylated polystyrene resins for solid-phase peptide synthesis.

Process for the preparation of graft copolymers

Abstract: Process for the preparation of thermoplastic graft copolymers which comprises heating for about 15 seconds to 60 minutes, with mixing, a trunk copolymer of at least two monomers, at least one of said monomers providing amine-reactive sites taken from the group consisting of the anhydride group, e.g., maleic anhydride; a vicinal pair of carboxylic groups and a carboxylic acid adjacent to an alkoxycarbonyl group, wherein the alkoxy group contains up to 20 carbon atoms, and at least one of said monomers containing no amine-reactive sites, and at least one side chain polymer having per chain one active amine site taken from the group consisting of primary and secondary amines, the remainder of said side chain polymer being substantially unreactive with the reactive sites, e.g., amino-substituted polycaprolactam, polylaurolactam, polyethylene oxide, etc., of the trunk copolymer. The process provides control of the type and length of the side chain polymer grafted onto the trunk copolymer. Plastic graft copolymers are included, specifically those containing one or more side chain polymer types with the proviso that when only one type side chain polymer is present the side chain polymer contains only one nitrogen atom, said atom being found in the active amine site.

Rubber-modified dicarboxylic acid imide copolymers

Abstract: Rubber-modified copolymers comprising 5 to 40 weight percent of an elastomer and 95 to 60 weight percent of a copolymer containing 1 to 50 mole percent of an imide derivative of an ethylenically unsaturated dicarboxylic acid monomer and 99 to 50 mole percent of one or more monomers copolymerizable therewith are prepared by the reaction of aqueous ammonia or amines with an aqueous suspension of a rubber-modified copolymer of the copolymerizable monomers and an ethylenically unsaturated dicarboxylic acid, anhydride, or half acid derivative. The reaction is carried out at a temperature between 125° and 200° C. at autogenous pressure for between 0.5 and 48 hours. The imide products can be recovered in the form of discrete particles, such as beads or pellets, if desired.

Backsizing carpet with hot melt composition of ethylene copolymer, atactic polypropylene and vulcanized rubber

Abstract: Hot melt compositions containing copolymer of ethylene and vinyl acetate and/or alkyl acrylate wherein the alkyl group contains 1-18 carbon atoms; atactic polypropylene; and vulcanized rubber which are particularly useful as hot melt carpet backing adhesives and as hot melt pressure sensitive adhesives.

Synthesis and properties of alternating poly(Lys‐Phe) and comparison with the random copolymer poly(Lys51, Phe49)

Abstract: The alternating copolypeptide poly(Lys-Phe) was obtained by synthesis and polymerization of the respective tetrapeptide Conformation and conformational transitions in aqueous solutions and in water–organic solvent mixtures were determined and compared with those of the random copolymer poly(Lys51,Phe49) by circular dichroism measurements The alternating copolymer reveals a very strong tendency to adopt the β structure, which is accomplished by raising the pH or by adding sodium perchlorate or methanol Partial α-helical conformation, however, is obtained in the presence of 10–20% of the strong helix-forming solvent hexafluoroisopropanol The random copolymer reveals a much weaker preference for the β structure It assumes the α helix in mixtures of water with hexafluoroisopropanol and also in those with methanol As was already reported by Peggion et al and confirmed by the present work, the addition of sodium perchlorate also leads to the helix conformation [(1972) Biopolymers11, 633], whereas β structure is obtained by raising the pH [(1970) Macromolecules3, 194] These studies reveal the significance of affinities determined by near neighbor interactions in polypeptides

The crystallinity of ionomers

Abstract: Ionomers are a recently developed class of copolymers consisting of a hydrocarbon repeat unit such as ethylene or butadiene and an ionized carboxylic acid group such as ionized acrylic or methacrylic acid. In this paper measurements of crystallinity in poly(ethylene-methacrylic acid) ionomers from DSC endotherms and polymer densities are shown to be in good agreement. The effect of annealing on the DSC endotherms of acid copolymers and ionomers and on the small-angle x-ray scattering of a poly(ethylene-methacrylic acid) ionomer is presented. It is shown that annealing results in the appearance of a secondary endotherm and a shift of the crystalline x-ray scattering to smaller angles. The data are interpreted in terms of an ionomer crystallinity model in which the hydrocarbon portion of the ionomer crystallizes into folded-chain lamellae.

Determination of surface car☐yl groups in styrene/itaconic acid copolymer latexes

Abstract: The modes of distribution of acid monomer in two styrene/itaconic acid copolymer latexes prepared with varying emulsifier types were estimated by conductometric titration. The concentrations of acid bound at the surface of the latex particles (“surface bound”) and “free” acid in the water phase can be determined in a single conductometric titration. The concentration of acid “buried” within the latex particles was obtained from the differences between the charge of acid during polymerization and the conductometric titration results. It was found that a larger particle size latex had much lower concentration of “total bound” and “surface bound” acids and higher “free” acid concentration than a smaller particle size latex. Although conductometric titration is suitable for determining the loci of car☐yl groups in polystyrene latexes, it may not apply to all car☐ylated latexes. Analysis of the isolated water phase of styrene/itaconic acid copolymer latexes by G.P.C. indicated the presence of oligomers containing weak acid groups with MW ranging between 2500 and 5000. These oligomers are generated “in situ” during latex polymerization and may become important in conferring adequate latex stability during preparation of car☐ylated latexes of low emulsifier content.

Composition and process

Abstract: There are disclosed novel photodegradable polymeric or plastic compositions comprising at least one organic polymer or copolymer and at least two different aromatic carbonyl photosensitizers.

Cements comprising acrylic acid/itaconic acid copolymer and fluoroaluminosilicate glass powder

Abstract: A cement-forming liquid suitable for use as a component of a poly(carboxylate) cement comprises an aqueous solution of a copolymer of acrylic acid, the copolymer having an average molecular weight of less than 20,000, and the solution having a viscosity of less than 50 poise.

Butadiene-styrene copolymer-cement composition and method of preparation

Abstract: 1. A cement .Iadd.mortar .Iaddend.composition comprising a mixture of Portland cement, mineral aggregate, about 5%-25% based on the weight of said Portland cement of styrene-butadiene-1,3 copolymer having a styrene to butadiene weight ratio of about 30:70 to 70:30, water in amount not in excess of about 40% based on the weight of said Portland cement, and, based on the weight of said copolymer, (a) 2-10% of non-ionic surfactant, (b) 1-7.5% of anionic surfactant, at least 15% of which is a sodium alkyl sulfate in which the alkyl group contains 9-17 carbon atoms, and (c) .[.1-5% of.]. polyorganosiloxane fluid surfactant, .Iadd.in an amount equal to about 2.5% of a polyorganosiloxane emulsion containing 29% of the polyorganosiloxane .Iaddend.the sum of (a) and (b) not exceeding about 14% by weight of said copolymer and the weight ratio of (a) to (b) being within the range of about 0.7:1 to 10:1.

Graft copolymer in polyamide polyethylene blends

Abstract: Polymeric blend of 60 to 90 parts by weight of a polyamide, e.g., polyhexamethylene adipamide or polycaprolactam, and 40 to 10 parts by weight of polyethylene or crystalline copolymer of ethylene, e.g., ethylene and methacrylic acid, characterized in that there is present in the blend 1.8 to 8.0 parts by weight of a thermoplastic graft copolymer consisting essentially of a trunk copolymer derived from ethylene and a comonomer providing amine-reactive sites and polycaprolactam side chains linked to said reactive sites through amide or imide linkages. The modified blends are useful as injection molding resins, for wire jacketing, etc.

Polyamide/polyolefin plastic graft copolymers

Abstract: Plastic graft copolymers consisting essentially of a crystalline trunk copolymer derived from ethylene and a comonomer providing amine-reactive sites selected from the group consisting of an anhydride group, a vicinal pair of carboxylic groups and a carboxylic group adjacent to an alkoxycarbonyl group, the alkoxy group having up to 20 carbon atoms, preferably 1 to 4 carbon atoms, and side chain polymers linked to said reactive sites through amide or imide linkages, the side chains having an average degree of polymerization of 5 to 30, preferably 6 to 10, and being derived from monomers selected from the group consisting of caprolactam or laurolactam, said graft copolymer having a polyamide content of 15 to 50 percent by weight based on the weight of graft copolymer with the proviso that the graft copolymer has two DTA melting points, one at 80° to 115°C. and the other at at least 165°C., preferably at 175 to 200°C. when polycaprolactam side chains are present and at least 150°C., preferably 150° to 170°C., when polylaurolactam side chains are present. Preferably, the comonomer is maleic anhydride, half ester of maleic acid or the half ester of itaconic acid. The trunk copolymer preferably contains 85 to 99 percent by weight ethylene.

Cyclopolymerization. II. Mechanism of the free-radical polymerization of N-n-propyldimethacrylamide

Abstract: The mechanism of cyclopolymerization was investigated by using N-n-propyldimethacrylamide (PDMA). Completely cyclized polymers were formed on polymerization of PDMA by a radical initiator. Moreover, those copolymers of PDMA and various monomers, such as styrene, methyl methacrylate, and vinyl acetate, obtained did not contain any detectable pendent double bonds. The kinetic investigation showed that the termination reaction proceeded between the cyclized radicals. The attempted polymerization of N-n-propyl-N-isobutyrylmethacrylamide, the monofunctional counterpart of PDMA, was failed. These results appear to confirm that cyclopolymerization of PDMA proceeds through a concerted mechanism which has been proposed for the mechanism of the cyclopolymerization of various difunctional monomers. Measurement of the ESR spectra of propagating radical has, however, revealed that the rate-determining step of the cyclopolymerization of PDMA is not intermolecular propagation but intramolecular cyclization, which indicates that the cyclization reaction proceeds in a stepwise way. This apparent contradiction was explained based upon thermodynamic considerations.