Showing papers on "Polymer blend published in 1981"

Dynamics of fluctuations and spinodal decomposition in polymer blends. II

Abstract: We reconsider the initial growth process of the unstable concentration fluctuations when a polymer blend of A and B chains (NA = NB) is rapidly quenched into the unstable region. We correct an earlier result and now predict (i) that the unstable wavelength 2π/? is on the order of R0 (ideal chain radius) for the case of strong segregation, and (ii) the corresponding growth rate is proportional to the melt reptation diffusion constant. These results are consistant with the phase separation kinetics observed in polystyrene–poly(vinyl methyl ether) blends by Nishi, Wang, and Kwei.

Polymer blends and alloys—a review of selected considerations

Abstract: A brief overview of the important issues governing the behavior of polymer blends is presented. Thermodynamic issues which determine the phase behavior of blends are reviewed and qualitatively related to physical interactions between blend components. The influence of melt processing conditions on the resulting properties and behavior of both miscible and immiscible blends is reviewed. The physical properties of blends are reviewed and illustrated by examples from recent work on miscible blends of polycarbonate with a copolyester and on the immiscible blends of polystyrene with high density polyethylene.

Compatibilized polymer blends

Abstract: Compatibilized polymer blends are described comprising a blend of olefin polymer, nitrile rubber, and a compatibilizing amount of block copolymer comprising nitrile rubber compatibilizing segments and olefin polymer compatibilizing segments.

Polymer blends containing polymer of β-hydroxybutyric acid and chlorine or nitrile group containing polymer

Abstract: Polymer blends containing (i) 0.2-95% by weight of a high molecular weight β-hydroxybutyric acid homo- or copolymer and (ii) a polymer containing at least 25% by weight of chlorine or nitrile groups, such as chlorinated polyethylene, polyvinyl chloride, or a high acrylonitrile resin. In small quantities the β-hydroxybutyric acid polymer acts as a processing aid for the chlorine or nitrile containing polymer. In larger quantities the properties of the β-hydroxybutyric acid polymer or the chlorine or nitrile containing polymer are improved.

Thermoformable polymer blend composition

Abstract: A thermoformable polymer blend composition comprising at least 50% by weight of an olefin polymer such as polyethylene or polypropylene, from 10 to 48% by weight of a styrene polymer and from 2 to 40% by weight of a thermoplastic styrenic block copolymer rubber, preferably a styrene-butadiene-styrene block copolymer, which acts as a compatibilizer for the olefin and styrene polymers in the blend. This blend can be formed on conventional machinery to give products having the beneficial properties of both types of polymers.

Phase Separation and Viscoelastic Behavior of Semicompatible Polymer Blends: Poly(vinylidene fluoride)/Poly(methyl methacrylate) System

Abstract: Phase Separation and Viscoelastic Behavior of Semicompatible Polymer Blends: Poly(vinylidene fluoride)/Poly(methyl methacrylate) System

Water soluble films of polyvinyl alcohol and polyacrylic acid and packages comprising same

Abstract: Films which are rapidly soluble in cold and warm water are formed from blends of water soluble polyvinyl alcohol (partially hydrolyzed polyvinyl acetate) and polyacrylic acid. The polymers are compatible and form homogeneous mixtures from which clear, transparent, non-tacky, easily handleable, mechanically strong films can be formed. The films are stable at both low and high humidity conditions, i.e., the films do not become brittle or tacky and retain their high rates of dissolution in water even after being stored in low or high humidity environments at both high and low temperatures. Further, improvements are achieved by incorporating a plasticizer into the polymer blend. The films are also heat sealable and biodegradable.

Thermoformable polymer blend composition comprising styrene polymer, olefin polymer and block copolymer

Abstract: A thermoformable polymer blend composition comprising at least 50% by weight of an olefin polymer such as polyethylene or polypropylene, from 10 to 48% by weight of a styrene polymer and from 2 to 40% by weight of a thermoplastic styrenic block copolymer rubber, preferably a styrene-butadiene-styrene block copolymer, which acts as a compatibilizer for the olefin and styrene polymers in the blend. This blend can be formed on conventional machinery to give products having the beneficial properties of both types of polymers.

Film-forming thermoplastic elastomeric polymer compositions

Abstract: There are disclosed film-forming polymer blends useful for the production of tubular blown film comprising EPM or EPDM elastomers, ethylene-vinyl acetate copolymers and a hydrocarbon oil plasticizer. The films exhibit resiliency and elasticity and high melt flow properties.

Blend of polycarbonate and wholly aromatic polyester

Abstract: A polymer blend which is capable of exhibiting an anisotropic melt phase and the ability to form shaped articles having improved mechanical properties is provided. The polymer blend comprises approximately 5 to approximately 75 percent by weight, based upon the total weight of the blend, of a polycarbonate and approximately 25 to approximately 95 percent by weight, based upon the total weight of the blend, of a melt processable wholly aromatic polyester which is capable of forming an anisotropic melt phase apart from the blend.

Film compositions from olefin polymer blends

Abstract: A heat sealable blend of a butene-1-ethylene copolymer, about 2 to 9% by weight of polypropylene and from about 0.02 to 1.5% by weight of high density polyethylene can be processed at high line speed in the blown-bubble extrusion process to form films or sheets exhibiting improved heat sealing characteristics, processability, tear strength and other properties.

Laminar thermoplastic film constructions

Abstract: Laminar thermoplastic film constructions comprising a layer of low density polyethylene bonded to a layer of a dissimilar polymer blend comprising high density polyethylene and polyethylene copolymers. In particular such copolymers comprise polyethylene copolymerized with another alpha olefin containing from about 3 up to about 15 carbon atoms. Such copolymers are also characterized by being linear, low density polymers having densities which are below about 0.94 grams/cc.

Composite hydrogel-forming article and method of making same

Abstract: Polymer blends capable of forming hydrogels upon immersion in water are bonded by heat and pressure alone to water-resistant polymer compositions compatible with vinyl lactam polymers to form laminates. Bonding can also be achieved by casting on the surface of the polymer composition a solution of the blend in a solvent inert to the polymer composition and evaporating the solvent. The blends are optically clear blends of vinyl lactam polymers or copolymers with water insoluble copolymers of a hydrophobic water-insoluble ethylenically unsaturated monomer, an ethylenically unsaturated monomer containing an acid group, and optionally a hydrophilic ethylenically unsaturated monomer free from acidic groups.

Thermoplastic polymer composition, products formed therefrom

Abstract: A fire resistant non-halogenated and flexible polymer composition comprises a polymer mixture with an inorganic filler. The polymer mixture comprises - as an elastomer component, an ethylene-copolymer or mixed polymerisate with a comonomer portion of at least 38% consisting of unsaturated ester comonomers, the elastomer being present in an amount by weight of least 50% of the polymer mixture, - as a plastomer component an ethylene-copolymer with an ethylene portion of at least 70%, the plastomer component being present in an amount by weight of at most 50% of the polymer mixture. The filler is a metal hydroxide used in an amount of 180 to 320% of the polymer mixture. The composition is particularly useful as sheathing for a cable. An extruder for processing the composition is also described.

Blend of polyarylene sulfide and wholly aromatic polyester

Abstract: A polymer blend which is capable of exhibiting an anisotropic melt phase, improved processability characteris­ tics and the ability to form molded articles having satisfac­ tory mechanical properties is provided The polymer blend comprises approximately 5 to approximately 95 percent by weight, based upon the total weight of the blend, of a polyarylene sulfide and approximately 5 to approximately 95 percent by weight, based upon the total weight of the blend, of a melt processable wholly aromatic polyester which is capable of forming an anisotropic melt phase apart from the blend Blend compositions containing high concentrations of wholly aromatic polyester (ie, at least 60 percent by weight wholly aromatic polyester) can be used to form fibers and films

Blend of polyalkylene terephthalate and wholly aromatic polyester and process for producing the same

Abstract: A process is provided for forming a novel polymer blend which exhibits an anisotropic melt phase wherein there is chemical interaction between previously formed polymeric blend components to yield a product which is capable of forming shaped articles having highly satisfactory mechanical properties. The process comprises intimately mixing together approximately 50 to 75 percent by weight of polyalkylene terephthalate and 25 to 50 percent by weight of a melt processable polyester which is capable of forming an anisotropic melt phase. A post-polymerization subsequently is conducted in the solid phase in a non-oxidizing atmosphere at a temperature within the range of approximately 250° to 300° C. for a period of time in the range approximately 8 to 72 hours to yield the desired chemical interaction between the previously formed polymeric blend components.

Viscosities of molten polymer blends

Abstract: Pairs of four thermoplastic resins, polystyrene, poly(methyl methacrylate), acetal homopolymer, and nylon-12, were intensively melt-blended in nine proportions from 0 to 100 percent. Capillary rheometry at 210°C was done on each blend; melt densities were also measured on most of them. The dependence of shear stress on Rabinowitsch-corrected shear rate was accurately represented, for all the blends, by a simple empirical model. The dependence of viscosity, at particular shear rates between 5 and 1000 s−1, on blend composition was examined and we fitted two viscosity-composition models to all the systems by least-squares procedures. The character of the dependence of blend viscosity on composition varied widely for the five binary systems studied, two being monotonic over the whole range of shear rate, two exhibiting clear minima and one displaying mixed behavior, with both a minimum and maximum viscosity seen at shear rates near 250 s−1. The McAl lister three-body model satisfactorily describes the viscositycomposition dependence in all five systems. A simpler blend rule was useful only in the monotonic systems, and even there it was inferior to the McAllister model.

Blend of sulfone polymer and wholly aromatic polyester

Abstract: A polymer blend which is capable of exhibiting an anisotropic melt phase, improved processability characteristics, and the ability to form shaped articles having satisfactory mechanical properties is provided. The polymer blend comprises approximately 5 to approximately 75 percent by weight, based upon the total weight of the blend, of a sulfone polymer which is selected from the group consisting of polyether sulfone having recurring units of the formula ##STR1## polysulfone having recurring units of the formula ##STR2## a mixture of the above sulfone polymers, and approximately 25 to approximately 95 percent by weight, based upon the total weight of the blend, of a melt processable wholly aromatic polyester which is capable of forming an anisotropic melt phase apart from the blend.

Process for forming blend of polyalkylene terephthalate and wholly aromatic polyester which exhibits an anisotropic melt phase

Abstract: An improved process for producing a polymer blend which exhibits an anisotropic melt phase and is capable of forming shaped articles having satisfactory mechanical properties (e.g. tensile strength, flexural strength, and Izod impact strength) is provided. The process comprises the steps of (a) post-polymerizing a melt processable wholly aromatic polyester which is capable of forming an anisotropic melt phase apart from the blend and (b) subsequently intimately mixing together approximately 85 to 95 percent by weight of the wholly aromatic polyester and approximately 5 to 15 percent by weight of a polyalkylene terephthalate. Accordingly, the wholly aromatic polyester which is capable of forming an anisotropic melt phase serves as the continuous phase in the resulting blend. The post-polymerization step is conducted at a temperature and for a period of time sufficient to increase the inherent viscosity of the wholly aromatic polyester by at least approximately 50 percent, preferably by at least approximately 100 percent. Each of the shaped article mechanical properties identified above is improved over that of the composition in the absence of the polyalkylene terephthalate. The polyalkylene terephthalate is preferably polyethylene terephthalate.

Viscoelastic properties of polystyrene–polycarbonate blends in melt

Abstract: Viscoelastic properties of polymer blend melts of polystyrene–polycarbonate were investigated in a wide range of temperatures, frequencies, and compositions. It was established that the more essential changes in viscoelastic characteristics took place at small concentrations of one of the components and at low frequencies, probably because of a putting down of the slow relaxation processes. The marked decrease in the viscosity of the melts takes place in the region of phase separation due to thermodynamic incompatibility of the components and is in a good correlation with the appearance of excess free volume in the system.

Polymer compositions comprising ethylene polymer blends

Abstract: Provided is a polymer composition having a melt index of 0.01 to 5.0 and a density of 0.880 to 0.940 prepared by blending 10 to 80 parts by weight of an ethylene/α-olefin copolymer having an intrinsic viscosity determined in decalin at 135° C. of 2.0 to 10 dl/g and a density of less than 0.91 which copolymer is obtained by copolymerizing ethylene with an α-olefin of C 3 to C 12 in vapor phase condition, with 20 to 90 parts by weight of an ethylene polymer having an intrinsic viscosity determined in decalin at 135° C. of not higher than 1.7 dl/g and a density not less than 0.950.

Ultra-high-index glass microspheres and products made therefrom with a fluoropolymer and an ester polymer blend

Abstract: Compositions comprising copolymers of methyl methacrylate and ethyl acrylate and of vinylidene fluoride and hexafluoropropylene may be blended to form transparent compositions of low refractive index, making them useful in retroreflective products as a layer in which glass microspheres are embedded.

An Introduction to Polymer Networks and IPNs

Abstract: An interpenetrating polymer network, IPN, can be defined as a combination of two polymers in network form, at least one of which is synthesized and/or crosslinked in the immediate presence of the other. An IPN can be distinguished from simple polymer blends, blocks, and grafts in two ways: (1) An IPN swells, but does not dissolve in solvents, and (2) creep and flow are suppressed.