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  • 1
    Electronic Resource
    Electronic Resource
    Effect of zinc-levulinic acid chelate compounds formed in furfuryl alcohol polymer concrete (1982)
    Springer
    Journal of materials science 17 (1982), S. 2067-2076 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract As part of an experimental programme to develop high early strength water-compatible furfuryl alcohol (FA) polymer concrete (PC) composites, the polymerization heat resulting from the use of various mineral and organic acid initiators was measured using a differential scanning calorimeter. The results indicated that, of the several initiators evaluated, the use of 1,1,1-trichlorotoluene (TCT)-zinc chloride (ZnCl2) system to cure a FA-water-saturated aggregate system yielded the highest early strength and the highest polymerization heat. The ZnCl2 solution used as part of the two-component initiator systems had a significant effect on the rate of polymerization of the FA monomer and the thermal stability of the composite. The latter resulted from an increase in the stiffness of the polymer chains due to the formation of zinc-FA chelate compounds. These were formed through reactions between the bivalent metallic Zn2+ ions dissociated from the ZnCl2 solution and the strongly ionized carboxyl groups of levulinic acid yielded by the cleavage of furan rings in an acidic medium. The thermal polymerization activation energy of FA monomer combined with the TCT-ZnCl2 system was calculated to be 98.6 kJ mol−1. The glass transition temperature, T g, and thermal decomposition heat of the system were 62° C and 220 kJ kg−1, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00540425
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  • 2
    Electronic Resource
    Electronic Resource
    Bentonite-based ammonium polyphosphate cementitious lost-circulation control materials (1986)
    Springer
    Journal of materials science 21 (1986), S. 2159-2168 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Bentonite-based cementitious materials have been formulated and evaluated in terms of their properties for use as cementitious lost-circulation control materials in geothermal wells at temperatures up to 300° C. The formulation which appears to have the highest potential as a new cementitious lost-circulation control material is composed of bentonite, ammonium polyphosphate, borax, magnesium oxide, and water. The appropriate combination of these ingredients results in the formation of slurries with viscosities and thickening times adequate to allow placement. After curing at elevated hydrothermal temperatures, the cement produced was characterized by a compressive strength 〉500 psi (〉3.45 MPa) at 2 h age, a permeability to water 〈2.0×10−4 Darcy, and a linear expansion 〉15%. The reaction compound responsible for the strength development at 300° C was found to be an assemblage of interlocking crystals composed of a grown thin-plate crystal. It was inferred that this microcrystalline cluster is associated with montmorillonite and ammonium polyphosphate-based complex formations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00547964
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  • 3
    Electronic Resource
    Electronic Resource
    Aspects of the adhesion and corrosion resistance of polyelectrolyte-chemisorbed zinc phosphate conversion coatings (1988)
    Springer
    Journal of materials science 23 (1988), S. 101-110 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The ability of polyelectrolyte macromolecules to suppress the crystal growth of zinc phosphate (Zn · Ph) conversion coatings depends primarily on the functional pendant groups. The extent of segmental chemisorption of macromolecules having carboxylic and sulphonic acid groups on the embryonic crystal faces was found to be considerably higher than that of macromolecules containing amine groups. The reaction products formed by intermolecular reactions between amide groups in polyurethane coatings and carboxylic acid groups on the outermost surface of polyelectrolyte-modified Zn · Ph in Zn · Ph-to-polymer adhesive joint systems played an essential role in developing interfacial adhesive forces. A highly dense precipitation of Zn · Ph derived from a zinc orthophosphate dihydrate-based phosphating solution contributed significantly to reducing the corrosion rate of cold-rolled steel. It also was determined that the presence of an internally diffused polyelectrolyte in the Zn · Ph layers further enhances the resistance to corrosion of Zn · Ph itself.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01174040
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  • 4
    Electronic Resource
    Electronic Resource
    Surface treatmet of sillimanite-based microspheres for strength enhancement of high-temperature lightweight cement composites (1987)
    Springer
    Journal of materials science 22 (1987), S. 4313-4325 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The compressive strength of high-temperature lightweight cementing materials containing sillimanite-based hollow microspheres as a filler can be improved by treating the surfaces of the microspheres with a calcium hydroxide-saturated solution at temperatures up to 200° C. The precipitation of an epitaxial layer formed by an interaction between the hot calcium hydroxide solution end the surface of the sphere played an essential role in developing favourable bonding characteristics at the interfaces and in promoting the hydration of the cement matrix. Bonding is associated with the formation of an intermediate layer of aluminium-rich calcium silicate hydrate, produced by an interfacial reaction of the cement paste with the epitaxy under the hydrothermal environment at 300° C. A dense intermediate layer consisting of a rim structure of 4μm thickness acts in cross-linking and coupling functions that serve to connect the cement matrix and spheres, thereby improving the interfacial bond strength. The presence of the epitaxial layer on the treated sphere surfaces leads to the formation of a well-crystallized tobermorite matrix phase, which is responsible for the development of strength in autoclaved lightweight cements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01132023
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  • 5
    Electronic Resource
    Electronic Resource
    Chemisorption mechanism and effect of polyacrylic acid on the improvement in bond durability of zinc phosphate-to-polymer adhesive joints (1987)
    Springer
    Journal of materials science 22 (1987), S. 722-736 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract It has been found that the outermost surface sites of polyacrylic acid-complexed crystalline zinc phosphate layers precipitated on cold-rolled steel surfaces act significantly to promote interfacial adhesive bonding to polymeric topcoats. This is the result of electrostatic internal diffusion and segmental chemisorption mechanisms of polyelectrolyte macromolecules either on newly precipitated crystal nuclei or on crystal growth sites during the primary zinc phosphate conversion process. The nature of the polymer-to-polymer chemical bond produced at the polymer-to-complex zinc phosphate precoat interfacial joints plays the key role in the achievement of long-term bond durability upon exposure to chemically corrosive environments. The locus of adhesive loss at the polymer-to-complex zinc phosphate joints after exposure to a hot acid solution was clearly identified to be cohesive failure in the crystalline precoat layers. A stable bond resulted from the formation of an interfacially produced hydrophobic structure by interactions between the polymer and the functional organic species existing on the complex precoat surfaces. The chemisorbed polyelectrolytes also served chemically to couple the organic coating and the inorganic zinc phosphate conversion layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01160794
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  • 6
    Electronic Resource
    Electronic Resource
    Influence of the high temperature treatment of zinc phosphate conversion coatings on the corrosion protection of steel (1991)
    Springer
    Journal of materials science 26 (1991), S. 1045-1050 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract An anhydrous α-Zn3(PO4)2 phase converted by the dehydration of hydrous zinc phosphate, Zn3(PO4)2·2H2O, crystal coatings in air at a temperature of approximately 300 °C, significantly enhances the corrosion resistance of steel, and also reduces the susceptibility of the crystals to alkaline dissolution. A subsequent α→γ phase transition at approximately 500 °C results in a poor protection behaviour, because of the formation of numerous microcracks on the crystal faces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00576784
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  • 7
    Electronic Resource
    Electronic Resource
    Alkali carbonation of autoclaved polymer-cement composites in Na2CO3-laden water at 300°C (1992)
    Springer
    Journal of materials science 27 (1992), S. 180-190 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Well cements resistive to high-temperature (∼300 °C) brines containing carbon dioxide (CO2) are needed for use in the completion of geothermal wells. Recent attempts to complete wells through aquifers containing ∼1000 p.p.m. concentrations of CO2 at ∼130 °C have shown severe deterioration of all conventional cement systems, with resulting cement and casing failures after only 90 days in service. As part of an ongoing research programme to develop hydrothermally and CO2-resistant cement formulations, studies were performed to determine the rate of alkali carbonation of autoclave-treated polymer-calcium aluminate cement composites upon exposure to Na2CO3-laden water at 300 °C. The results indicated that the formation of a calcium-complexed carboxylate polymer structure, resulting from the addition of an acrylic polymer in the cement, improved the compressive strength of the composite after a 1 day autoclave exposure, and minimized the carbonation rate over 30 days. However, biccholite→wairakite and triclinic→hexagonal anorthite transformations resulted in strength degradation after exposure for times up to 30 days. The polymer system found to be most effective for minimizing strength degradation and carbonation reactions was a carboxylated styrene-butadiene copolymer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00553854
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  • 8
    Electronic Resource
    Electronic Resource
    Interface between zinc phosphate-deposited steel fibres and cement paste (1992)
    Springer
    Journal of materials science 27 (1992), S. 2863-2872 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In an attempt to protect steel fibre reinforcements from corrosion and improve their adherence to cement pastes, we deposited a zinc phosphate (ZnPh) conversion coating on the surface of the fibres. At the interfacial contact zones between the cement paste and ZnPh, alkali-induced dissolution caused the dissociation of abundant PO 4 3− ions from the ZnPh. The interaction of PO 4 3− ions with Ca2+ ions from the pastes led to the formation of hydroxyapatite and brushite in the vicinity of the dissolved ZnPh surface. Such intermediate calcium phosphate compounds played important roles in (1) improving the cement-fibre interfacial bonds, and (2) repairing the damage of the ZnPh surfaces dissolved by alkali. These processes protected the steel fibre from corrosion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01154093
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  • 9
    Electronic Resource
    Electronic Resource
    Alkali carbonation of autoclaved polymer-cement composites in Na2CO3-laden water at 300°C (1992)
    Springer
    Journal of materials science 27 (1992), S. 180-190 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Well cements resistive to high-temperature (∼300 °C) brines containing carbon dioxide (CO2) are needed for use in the completion of geothermal wells. Recent attempts to complete wells through aquifers containing ∼1000 p.p.m. concentrations of CO2 at ∼130 °C have shown severe deterioration of all conventional cement systems, with resulting cement and casing failures after only 90 days in service. As part of an ongoing research programme to develop hydrothermally and CO2-resistant cement formulations, studies were performed to determine the rate of alkali carbonation of autoclave-treated polymer-calcium aluminate cement composites upon exposure to Na2CO3-laden water at 300 °C. The results indicated that the formation of a calcium-complexed carboxylate polymer structure, resulting from the addition of an acrylic polymer in the cement, improved the compressive strength of the composite after a 1 day autoclave exposure, and minimized the carbonation rate over 30 days. However, biccholite→wairakite and triclinic→hexagonal anorthite transformations resulted in strength degradation after exposure for times up to 30 days. The polymer system found to be most effective for minimizing strength degradation and carbonation reactions was a carboxylated styrene-butadiene copolymer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02403661
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  • 10
    Electronic Resource
    Electronic Resource
    Nature of interfacial interaction mechanisms between polyacrylic acid macromolecules and oxide metal surfaces (1984)
    Springer
    Journal of materials science 19 (1984), S. 4045-4056 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The mechanism for the adhesion of polyacrylic acid (PAA) coatings to oxidized metal surfaces has been studied. The work entailed studies of the mechanical and chemical interactions occurring at the interfaces between PAA polyelectrolyte macromolecules and iron (III) orthophosphate dihydrate or zinc phosphate hydrate (hopeite) crystalline films that were deposited on the metal surfaces. With respect to mechanical interactions, it was determined that the surface topography of the highly crystallized hopeite layers consisted of an open microstructure. This resulted in enhanced wettability of the oxide film by the polyelectrolyte macromolecules, thereby increasing the mechanical interlocking bond forces. Studies of the interfacial chemical reactions indicated that the conformation changes in the PAA macromolecules relate directly to the frequency of the magnitude of acid-base and divalent metallic ion crosslinking interactions between the proton-donating pendent COOH groups in PAA molecules and polar OH groups at hydrated oxide surface sites. Namely, the presence of numerous free nucleophilic ions existing on the deposited oxide film leads to a substantial increase in the coil-up and entanglement macromolecule density. These entangled complex macromolecules at the interfaces result in a decrease in the degree of chemisorption at the oxide film surfaces, whereas regularly oriented COOH groups produce strong interfacial chemisorption with the polar OH groups. Since the polyelectrolyte macromolecules have hydrophilic pendent COOH groups, the polymer structure which appears best for use as an adhesive and coating should have only enough hydrophilic COOH groups to occupy all available polar OH groups at the oxide metal surface sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00980770
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