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  • 1
    Electronic Resource
    Electronic Resource
    The Exchange of Radioactive Zinc between Cellulose and Sodium Hydroxide-Sodium Zincate Solutions. (1950)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 54 (1950), S. 772-777 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j150480a004
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Improvement of capillary penetration of liquids into wood by use of supersonic waves (1970)
    Springer
    Wood science and technology 4 (1970), S. 189-194 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary The effect of supersonic waves on the capillary penetration of liquids into wood was found to be positive or negative depending upon a number of factors. The penetration of non-polar compounds like paraffins and aromatic hydrocarbons was not improved by using supersonic waves. The effect of supersonic waves, however, became positive by introducing one or several hydrophilic groups into straight hydrocarbon chains. Diluting hydrocarbons containing hydrophilic groups with non-polar solvents reduced the positive effect of supersonic waves until it became negative below a certain concentration. Polyfunctional alcohols exhibited an optimum effect at certain concentrations when diluted with water. These concentrations correspond to alcohol-water blends of maximum affinity to the surface of wood. Supersonic waves improved the capillary penetration of water when the surface tension was reduced by using surface active agents. In fields were the rapid and thorough impregnation of wood by various liquids is important, supersonic waves can under certain conditions aid this process and be of practical use.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00571853
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    The effect of aging on the ultrastructure of wood (1975)
    Springer
    Wood science and technology 9 (1975), S. 87-98 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Wood samples varying in age from 900 to 4400 years were investigated with the electron microscopes (TEM, SEM) and polarized light microscopy as well as by analysis of the mechanism of fracture. The weakest parts of the structure, and therefore the most susceptible to failure, are the middle lamella/S1 region and the interfibrillar matrix. Parts of the wall exhibit fissures, cracks and loss of adhesion, not found in recent wood. Studies of the fractured surfaces confirm a change in the micromorphology of the old wood samples. In spite of the breakdown of certain elements at ultrastructural level the samples had retained almost their normal macroscopic appearance and properties. As long as the main reinforcing structural elements, the microfibrils, remain intact, the major properties of wood do not apparently undergo drastic changes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00353388
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    The hydrophobic and water-repellent properties of wattle bark extractives (1974)
    Springer
    Wood science and technology 8 (1974), S. 138-147 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Based on the fact that bark is an almost perfect water barrier and assuming that bark is impregnated with materials which aid in rendering it impermeable to water, the hydrophobic and water-repellent properties of several bark extractives were investigated. Products obtained after extraction with polar and non-polar solvents showed widely different properties. Some were extremely hydrophobic and water-repellent with a water-solid-air contact angle higher than 100°. These were the products obtained from extraction with benzene and mineral turpentine. Alcohol and acetone extractives had contact angles as low as 23° but coatings from some of these materials nevertheless had a high efficiency as water barriers. The efficiency of the various extractives as water repellents or water barriers was determined by coating wood with 10 per cent solutions of the extractives in different solvents and determining the extent to which water could be prevented from being absorbed and causing swelling of the wood and thereby reduce the dimensional changes of the wood. The extractives obtained with nonpolar solvents were extremely efficient as true water repellents while the polar aleohol extracts were far better than could be expected from their almost hydrophilic properties. Nature has therefore provided for hydrophilic film-formers combined with hydrophobic materials which act as a double line of defence against water absorption. The hydrophilic extractives, in addition, act as a bridging agent between the strongly hydrophobic extractives and the hydrophilic cell wall material. Since some of the extractives from wattle bark have excellent hydrophobic properties, and since this bark is available in large quantities as a waste product after tannins have been extracted, the utilization of certain wattle bark extractives as water repellents could be economically attractive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00351368
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  • 5
    Electronic Resource
    Electronic Resource
    The hydrophobic properties of bark extractives (1971)
    Springer
    Wood science and technology 5 (1971), S. 190-199 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary The hydrophobic properties of benzene-soluble extractives from the bark of Pinus radiata were studied by determining the water-solid-air contact angle and the resistance to water penetration. The material contained in the bark extract possessed wax-like and film-forming properties. It was highly hydrophobic with a contact angle with water of about 98°. Wood samples were impregnated with bark extract in order to study the ability of the hydrophobic bark extractives to prevent preferential wetting with water and the displacement of the impregnant from the hydrophilic wood surface. The wax-like material deposited from the bark extracts showed a remarkable affinity for wood as revealed by the high degree of resistance to water penetration and wetting of the treated wood even after several wetting-drying cycles which otherwise tend to break down the bonds and adhesion between a hydrophilic solid and a hydrophobic coating. Hydrophobic or film-forming additives did not improve the ability of bark extractives to protect a hydrophilic solid from water. The properties of the bark extractives as a water repellent and a water barrier could therefore be assumed to be as near perfect as possible. Nature seems to have solved the problem of producing one single, although complex, material with two properties which are extremely difficult, maybe impossible, to combine in a single synthetic material: one of high affinity for a hydrophilic solid and another of extreme water repellency and resistance to water. The in situ conditions prevailing in the bark tissue, combining bark extractives and cell walls of various anatomical structures, must therefore represent a rather unique and for this specific purpose highly efficient two-phase hydrophobic-hydrophilic solid system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00353681
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    Paper (German National Licenses)
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