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  • 1
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 622-626 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The synthetic membranes currently used for soil stabilization and road construction are mainly made of polypropylene and of polyesters. They are used separately for each application. The polymer used has an effect on the wettability and, the permeability of the membrane. The polypropylene membranes, for instance, have a zero wettability, whereas it is high for polyester membranes. This paper reports on the mechanical properties and the permeability of mixtures of polypropylene (PP) and poly(ethylene terephthalate) (PET). The elastic modulus of the mixture was at a minimum for a 50/50 mixture. For the other compositions, the moduli gave a positive deviation as compared with the additivity equation results. This is probably due to the fact that pure PET has a fragile behavior at the temperature at which the mechanical tests were run. This 50/50 composition corresponds to the domain where a phase inversion occurs. The permeability to water vapor gave an S-shape curve that is typical of a “mixture” of immiscible polymers. The diffusion of the water molecules is controlled by the continuous phase. To compatibilize the two homopolymers, a 94/6 copolymer of PP and of polyacrylic acid was added, at various levels, to a 60/40 mixture of PET and PP: This did not affect markedly the elastic modulus. The yield stress increased, however, indicating that we had a better adhesion and that the copolymer seems to have a certain emulsifier effect, increasing the quality of the dispersion.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Brookfield, Conn. : Wiley-Blackwell
    Polymer Composites 9 (1988), S. 426-433 
    ISSN: 0272-8397
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Acid-base interaction parameters were measured by inverse gas chromatography over broad temperature ranges for Poly(vinyl chloride), plasticizer, and CaCO3 fillers. Mixing was performed by three routes. In one, all components were added simultaneously, while in others two of the components were premixed, the third ingredient being added subsequently. Mixing was carried on to equilibrium torque readings. The energy requirement for mixing was found to depend on the interaction balance among the components, and to vary with the procedure selected. Minimum requirement was associated with the simultaneous introduction of all ingredients. Higher energies were needed in sequential mixing schemes, presumably because equilibrium partitioning of components was hindered in these instances. Initial mechanical properties of the compounds did not vary greatly with preparation procedure, but upon aging, mechanical property variations became quite evident. Component repartitioning, driven by shifting interaction balances at aging and at test (room) temperatures are cited as responsible. The kinetics of attaining equilibrium mechanical properties also were found to vary with mixing procedure and to respond to the interaction balance concept.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0272-8397
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The specific interaction characteristics and the inherent agglomeration of variously surface coated rutile pigments have been assessed, respectively, by inverse gas chromatographic and powder rheological methods. Standardized methods were used to disperse the pigments in polyethylene and chlorinated polyethylene. Measurements were made of energy requirements for dispersion and of the quality of dispersion attained. It was found that in the non-polar polyethylene matrix, dispersion processes depended on the strength of pigment agglomerates, but not on the specific interaction potential of the solids. Conversely, in the acidic chlorinated polyethylene, acid/base interactions influenced dispersion but the process was independent of inherent pigment agglomeration.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Brookfield, Conn. : Wiley-Blackwell
    Polymer Composites 6 (1985), S. 201-208 
    ISSN: 0272-8397
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The dispersion behavior of calcium carbonate (CaCO3), of mica and of sized sand fractions in poly(vinyl chloride) (PVC) and polypropylene (PP) has been evaluated using fillers with various surface treatments. Mechanical properties of the compounds were also studied in order to question the role of interfacial forces in the context of dispersion and property parameters. Surface characteristics of polymers and fillers were obtained from inverse gas chromatography data. It has been shown that in the acidic PVC matrix, rapid dispersion of fillers is favored when strong acid-base interactions exist at polymer filler contacts. Similarly, mechanical properties at large extension are improved by acid-base interactions. In contrast, for polypropylene (PP), a van der Waals force material, fillers without pronounced acid or base surface characteristics tend to disperse more rapidly and produce mechanically stronger compounds. The importance of filler surface properties and thus, apparently, of acid-base interfacial forces varies directly with increasing particle size of the dispersed phase.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Brookfield, Conn. : Wiley-Blackwell
    Journal of Vinyl and Additive Technology 11 (1989), S. 81-83 
    ISSN: 0193-7197
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A Co-60 source was used to irradiate compositions based on PVC, and containing plasticizer additives including DIDP and TOTM, and chlorinated PE (CPE). Polyfunctional acrylic monomers were used as crosslinking agents, and irradiation dosages to about 8Mrad were applied to crosslink the compounds. Analyses included crosslink density estimates from solvent swelling data, and stress/strain evaluations of mechanical responses. It was shown that plasticizers reduce the crosslinking efficiency of irradiation, TOTM being the better inhibitor. The presence of CPE counteracts the trend. Mechanical properties differentiate strongly between the use of difunctional and trifunctional crosslinking agents. The latter produce networks at higher dosages (Eq 〉 4Mrad) characterized by two apparent yield stresses. This suggests the presence of two (or more) distinct network structures. DSC scans of partially crosslinked samples support the contention. The work indicates the importance of composition-property relationships in multicomponent vinyl systems.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Brookfield, Conn. : Wiley-Blackwell
    Polymer Composites 7 (1986), S. 295-301 
    ISSN: 0272-8397
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The dynamic mechanical responses of rutile-filled, chlorinated polyethylene (CPE) were studied as a function of temperature, of filler loading, and of filler surface condition. An objective was to establish the influence of matrix-filler interactions on mechanical properties. Necessary information on potential interactions between matrix and filler was obtained from inverse gas chromatographic data, in the form of an acid-base interaction parameter, Ω. The damping peak in filled CPE compounds was depressed by the pigment, as called for by theoretical models. The magnitude of the effect exceeded expectations, however, and clearly depended on the strength of interfacial interactions. These were consistent with the acid-base ranking of CPE and the various rutiles, as given by Ω. It has been postulated that in the presence of acid-base interactions, an immobilized layer of polymer in the vicinity of solid particles increases the effective particle dimension, thereby accounting for the observed variations in relative damping. Additional effects of matrix-filler interaction were noted in the variation of storage moduli with loading and temperature. Again, the effects tend to be more pronounced when significant specific interactions between matrix and solid are operative. These observations point to the inadequacy of existing models as interpretative bases for dynamic mechanical properties in systems with significant specifie interactions among their components.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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