ISSN:0021-8871    

DOI:10.1002/jctb.5010121110

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractSodium soaps of highly branched saturated monocarboxylic acids, in particular those containing 15–20 carbon atoms, are valuable substitutes for both rosin acid soaps and sodium stearate in cold emulsion polymerisation SBR recipes such as ASTM types 1500, 1502, and 1509. Indications are that they possess various process advantages over the normal types of emulsifier. At comparable concentrations they give higher rates of polymerisation than do the commercially available rosin acid emulsifiers and their solutions do not gel at temperatures between 5° and 20°, as is the case with sodium stearate. Moreover, they show a relatively good tolerance towards hard water.Potassium, ammonium and lithium salts of these synthetic acids are also excellent emulsifiers for the preparation of SBR lati

ISSN:0021-8871    

DOI:10.1002/jctb.5010121101

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractA good yield (97%) of MgBH4is obtained by interaction of magnesium hydrides with diborane in a glycol ether medium or a mixture of glycol ether and benzene (1:3) at 80°. Interaction of the borohydride with boron trichloride in benzene at ∼80° gives a 94% yield of dibor

ISSN:0021-8871    

DOI:10.1002/jctb.5010121102

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractThe effect of Dead Sea water on pastes and mortars of normal and sulphate‐resisting Portland cement has been studied. The principal reaction products include magnesium hydroxychloride, calcium chloroaluminate and hydrated magnesium silicate. The use of Dead Sea water as mixing water in the preparation of the bars appears to enhance their stability. The reasons are discusse

ISSN:0021-8871    

DOI:10.1002/jctb.5010121103

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractThe influence of pH on the surface electrokinetic properties of the rutile‐solution interface has been studied; below pH 3.5 the surface is positively charged and above this pH value it is negatively charged. Adsorption of dodecyl sulphate anions from aqueous solution on to the rutile surface is influenced profoundly by the electrokinetic properties of the mineral‐solution interface, the surface showing decreased adsorption of anions with increase in pH. Flotation tests have shown that at constant pH, the flotation rate increases with collector concentration and that for a fixed collector concentration, a decrease in flotation rate occurred as the pH increased from 3 t

ISSN:0021-8871    

DOI:10.1002/jctb.5010121104

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractSamples of active titania have been prepared by the hydrolysis with steam of several titanium tetra‐alkoxides under neutral ion‐free conditions, and their surface properties studied by nitrogen adsorption at − 195.8°. It is shown that for a series of normal alkoxides hydrolysed from solution in either benzene or the parent alcohol, the product has a stable surface area close to 300 m.2g.−1, being porous with a mean pore radius of about 20 A. No appreciable ageing was observed except when the titania gel was kept in contact with the boiling mother‐liquor. By hydrolysis in acidic and basic media and subsequent alteration of the pH, a variation in pore size wa

ISSN:0021-8871    

DOI:10.1002/jctb.5010121105

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractSilica gels were prepared by adding sodium silicate to acetic acid, or acetic acid‐sodium acetate buffer, until the pH reached 4.64, the addition of silicate being made rapidly (over 1–2 min.) or slowly (over about 30 min.). Adsorption isotherms of nitrogen were determined on the outgassed samples at − 195.8° and used for the calculation of surface areas and pore volumes.The gels prepared either byrapidaddition of silicate to acid, over the concentration range 2–30%, or from the buffer (initial pH 3.78), were all microporous and had very similar surface properties. On the other hand, the surface properties of those gels prepared by theslowaddition of silicate depended on the concentration of acid used, the surface area of the sample prepared from 30% acetic acid being half that of the one from 10% acid. It is suggested that this effect is associated with the loss of some of the smaller primary particles, which occurs as the concentration of polysilicic acid is increased and the pH allowed to change slowly during the

ISSN:0021-8871    

DOI:10.1002/jctb.5010121106

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractA new type of selective ion‐exchanger was prepared by condensation of resorcylfluorone with formaldehyde. The structure units of fluorone, retain their ability for binding germanium even after their incorporation into the three dimensional macrormolecular matrix. The ion‐exchange resin formed in this way sorbs germanium selectively even from concentrated solution of acids and salts, e.g. from azeotropic hydrochloric acid. The desorption of germanium can be carried out by elution with water. This procedure may be used for separating germanium from arsenic and iron (and from further elements) in chloric acid solution the germanium being finally isolated as dioxide in a very pure f

ISSN:0021-8871    

DOI:10.1002/jctb.5010121107

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractThe main features of the Immersion Wheel‐tracking test and its use as a laboratory tool in the study of bituminous binder/aggregate adhesion are described. The importance of various factors, including the procedure for preparing the test specimens, control of the temperature of the water bath and the effect of the depth of immersion of the samples in the bath are discussed. Finally, some consideration is given to the practical significance of the results of the test in relation to the stripping of binders from aggregates on the roa

ISSN:0021-8871    

DOI:10.1002/jctb.5010121108

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractThe post‐war pattern of petroleum refining in Europe resulted in a large increase in the running of Middle East crudes, from which were obtained bitumens of relatively unknown quality. For this reason, a field experiment was initiated in 1954 to compare on the road in an open‐textured carpet, the performance of seven bitumens from Middle East and traditionally accepted Western Hemisphere sources. Two types of stone were used in the experiment.The road surface was assessed annually by an independent evaluation panel, and samples periodically taken from the road were examined in the laboratory for changes in properties occurring during the life of the road.The differences in road performance given by the seven bitumens were small but, taken over all, bitumens from one of the Middle East sources gave rather better service than the two binders from the Western Hemisph

ISSN:0021-8871    

DOI:10.1002/jctb.5010121109

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY