Showing papers on "Polymer blend published in 1975"

The effect of mixing on the modes of dispersion and rheological properties of two‐phase polymer blends in extrusion

Abstract: An experimental study was carried out to investigate the effect of mixing on the state of dispersion and rheological properties in the two-phase flow of polymer blends. For the study, blends of polystyrene and polypropylene were used, and two mixing devices were employed: a single-screw extruder combined with a “static mixer,” and a twin-screw compounding machine. Materials of various blending ratios were extruded at a constant temperature (200°C) through a capillary die having an L/D ratio of 20 (D = 0.125 in.). The state of dispersion in the two-phase system was investigated from pictures taken of the microstructure of the extrudate samples. It was found that different mixing devices have a profound influence on the state of dispersion of one polymer in another. Also determined were the rheological properties of the two-phase system investigated, from wall normal stress measurements. Our results show that, when shear stress is used as a parameter, the melt viscosity goes through a minimum, whereas the melt elasticity goes through a maximum. This is regardless of the type of mixing device employed, although the shapes of the curves are affected by the type employed. It is suggested that shear stress, instead of shear rate, be used in correlating the viscoelastic properties of two-phase polymer systems.

Gas permeation of polymer blends. I. PVC/ethylene–vinyl acetate copolymer (EVA)

Abstract: The transport behavior of O2 and N2 were studied for series of physical blends of PVC with EVA having different vinyl acetate (VAc) contents in the EVA (45 and 65 wt-%) and using different milling temperatures (160° and 185°C). The polymer blends were further characterized by dynamic mechanical measurements, density measurements, and x-ray diffraction. At higher VAc content in EVA and with higher milling temperature, the rate of permeation (P) and the rate of diffusion (D) decrease, and the activation energy of D (from Arrhenius plots) increases. Furthermore, the experimental density values of PVC/EVA-45 blends agree well with calculated values, assuming volume additivity of the two components, while those of PVC/EVA-65 blends are higher than the calculated densities. These results are interpreted as due to denser packing of polymer molecules and increased PVC-EVA interaction at higher VAc content and with higher milling temperature, indicating better compatibility between the blend components. The x-ray diffraction data give no evidence of crystallinity. Sharp increases in P and D values at about 7.5% EVA (by weight) are found for PVC/EVA-45 blends (in agreement with our previous work) but not for PVC/EVA-65 blends. This is interpreted as due to a phase inversion at increasing EVA content in the former blends but not in the latter blends. The dynamic mechanical measurements show that the PVC/EVA-65 blends milled at 160°C behave largely as semicompatible systems with maximum interaction between the two polymers at compositions of about 50/50 by weight.

Slow-release air freshener polymer-blend composition

Abstract: Slow-release air freshener compositions having favorable depletion characteristics comprise an odorant (perfume) intimately dispersed in a polymeric mixture comprising 10-50% by weight of a certain block copolymer, 2-10% by weight polystyrene and 30-50% by weight of ethylene vinyl acetate copolymer.

Gas permeation of polymer blends. II. Poly(vinyl chloride)/acrylonitrile–butadiene copolymer (NBR) blends

Abstract: The transport behavior of He, O2, N2, and CO2 in a series of PVC/NBR polymer blends with varying acrylonitrile (AN) content in the NBR component has been studied at 25° and 50°C. In addition, measurements of density, crystallinity, and thermal expansion coefficients were carried out. The transport behavior of these blends is similar to previous result for PVC/EVA.1. With increasing AN content in NBR, the permeability (P) and diffusivity (D) of the permeants decreased while the activation energy for diffusion (ED) increased. For the polymer blends, better additivity of permeability and diffusivity was observed with increasing AN content in the NBR component. The polymer blends also showed increasing volume contraction with increasing AN content in the NBR component. These effects have been discussed as due mainly to increased polymer–polymer interaction causing reduced segmental mobility and increased compatibility of the two polymers. The sorption values calculated from P/D ratios were largely irregular and fluctuated with the blend composition. They were less reproducible than other transport parameters, i.e., P and D measured separately. Several reasons for the irregular sorption behavior were proposed.

Vulcanizable compositions of a halogen-containing polymer and a diene-nitrile rubber having active halogen cure sites

Abstract: Compositions comprised of a polymer blend of a halogen-containing polymer and a diene/nitrile rubber having active halogen cure sites are covulcanized using a common cure system The halogen-containing polymers used in the polymer blend include the commercial polymers such as epihalohydrin polymers, polychloroprenes, fluoroelastomers, halogen-containing acrylates, and halogenated polyolefins The curative ingredients employed are those normally used for the cure of the halogen-containing polymer employed in the polymer blend

Polyurethane coated textile sheets

Abstract: POLYURETHANE COATED TEXTILE SHEETS Abstract of the Disclosure Polyurethane coated textile sheets are disclosed and a reversal process for their preparation, wherein the textile sheets are coated by means of a top coat solution with a polymer mixture comprising i) 50 to 90% by weight, based on the total polymer, of a substantially linear poly-urethane which is substantially free of reactive end groups and which has been prepared by a process which comprises reacting an organic dihydroxyl compound of molecular weight 500 to 4000 and an organic diol of molecular weight 60 to 450 with an aromatic-diisocyanate, ii) 0 to 50% by weight of a vinyl copolymer, and iii) 1 to 50% by weight of a diene graft copolymer, said polymer mixture having been applied to a release sub-strate prior to said coating process.

Polyvinyl butyral polymer mixture for making intermediate sheeting for laminated glass

Abstract: Mixtures of two distinct polyvinyl butyral grades, viz., one high viscosity and one low viscosity grade, both having a narrow molecular weight distribution exhibit good processing characteristics which nearly reach the performance of the high viscosity grades hitherto used.

Stretched polyester film from a polymer blend

Abstract: A transparent polyester film having excellent printability, flexing resistance and pinhole resistance and further excellent interlaminar strength, which is made from a polymer mixture or blend comprising (i) a polyester consisting essentially of a residue of dibasic acids wherein at least 80 % by mol is terephthalic acid and a residue of at least one glycol and (ii) a block copolyester consisting of a crystalline polyester (hard) segment having a high melting point and a soft polymer segment having a low melting point and a number average molecular weight of 400 to 8,000, said soft polymer segment having a low melting point being contained in an amount of 0.5 to 10 % by weight on the basis of the whole weight of the polymer mixture or blend, and said crystalline polyester segment having a melting point of at least 170° C when a polymer is produced by the monomers composing the segment alone and said soft polymer segment having a melting or softening point of 100° C or lower.

Thermoplastic elastomeric polymer blend

Abstract: A thermoplastic, elastomeric and reprocessable polymer blend comprising: A. 30 to 90 parts by weight of a terpolymer of ethylene, a different monoolefin, and dicyclopentadiene, the weight ratio of ethylene to different monoolefin being from 70/30 to 85/15, said terpolymer having a zero shear viscosity of not greater than 0.5 to 10 9 poises; and B. correspondingly 70 to 10 parts by weight of a polyolefin resin.

Preparation of thermoplastic elastomer

Abstract: PURPOSE: To prepare a thermoplastic elastomer with good elastic properties by the reaction of a curing agent with an intimate blend of a monoolefin copolymer rubber which was previously blended with a crystalline resin. COPYRIGHT: (C)1977,JPO&Japio

Heterophase adhesive compositions containing chlorosulfonated polyethylene for metal-selenium composites

Abstract: A xerographic member which comprises a conductive substrate having thereon an interfacial barrier layer in a thickness of about 0.5 to 3.0 microns. The barrier layer comprises a polymer blend or mixture of a polycarbonate, a polyether-ester-urethane, and a chlorosulfonated polyethylene and is overcoated with a photoconductive layer about 10 to 200 microns in thickness.

Dry-spun modacrylic filaments with improved coloristic properties

Abstract: The invention relates to dry-spun modacrylic filaments with improved coloristic properties based on a polymer mixture, which comprises at least one acrylonitrile-vinyl chloride copolymer and a chlorine-containing copolymer containing sulphonic acid ester groups or sulphuric acid ester groups.

Cross-linked block copolymer blends with improved impact resistance

Abstract: Polymer blends having high impact resistance after mechanical working are produced by blending together a non-elastomeric monovinylidene aromatic polymer such as polystyrene with an elastomeric copolymer, such as a block copolymer of styrene and butadiene, in the form of crosslinked, colloidal size particles.

Organosilicon compositions particularly suitable for the non-stick, rub-resistant treatment of cellulosic and synthetic materials

Abstract: Storage-stable organosilicon compositions are provided which are characterized in that, apart from 100 parts by weight of a diorganopolysiloxane polymer mixture and 1 to 15 parts by weight of an organohydrogenopolysiloxane polymer,they contain 0.001 to 0.1 part by weight of platinum in the form of a complex of the formula: ##STR1## in which the symbols R and R', which may be identical or differen, each represents a monovalent hydrocarbon radical having from 1 to 8 carbon atoms, or two of these radicals, together with the nitrogen atom to which they are attached, form a monovalent heterocyclic radical.

Process for processing disposed polymer mixture

Abstract: A method for treating a waste high-polymer mixture by fractionating the mixture consisting essentially of five groups of high polymers, i.e., polyolefinic, polystyrenic, polyvinyl-chloride, thermosetting, and natural high polymers, taking advantage of their dissimilar solubilities in different organic solvents, characterized in that the mixture is brought into contact with o-xylene, p-xylene, or m-xylene, the solvents being used either singly or in a combination of two or more, at temperatures within a certain range or ranges to dissolve and fractionate the polystyrenic and polyolefinic high polymers, and the polyvinyl chlorides in the remainder are dissolved and fractionated by using at least one solvent selected from the group consisting of tetrahydrofuran, cyclohexanone, dioxane, and methylethylketone and at a temperature within a certain range, whereby the waste mixture is fractionated into the groups of polyolefinic, polystyrenic, polyvinyl-chloride, thermosetting, and natural high polymers.

Blend of two chloroprene polymers

Abstract: A chloroprene polymer blend comprises a major proportion of a first benzene-soluble polymer of defined Mooney Viscosity formed by polymerisation in the presence of a xanthogen modifier and a minor proportion of a fluid benzene-soluble chloroprene polymer made in the presence of a defined quantity of modifier.

The structural color in the polymer blend of poly(methyl methacrylate) and polystyrene

Abstract: Morphologic and optical studies were performed on the coloring of poly(methyl methacrylate) (PMMA) and polystyrene (PS) opal sheet. It was concluded that the origin of color is the polymer structure itself. There exist three structures in the colored polymer blend: small PS spheres are dispersed in the PMMA matrix, and each PS sphere contains smaller PMMA spheres within it. The dimension of the smaller PMMA spheres is of the same order as the wavelength of visible or near-infrared light. The coloring measured by a spectrometer is well interpreted by the equation of structural color derived by Clewell qualitatively.