ISSN:0021-8871    

DOI:10.1002/jctb.5010140109

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractIn a study of the technology of the melt spinning of 6.6 nylon filaments of diameter in the range 30–100 μ, some new crystallisation phenomena have been noted. Because of the geometrical form of the filaments, cooling from the melt is extremely rapid. Solidification takes place in a fraction of a second, and further cooling to room temperature is also rapid. The polymer can be observed at various stages during its quenching, either by taking samples from the running filaments, or by examining it whilst it is running.Under these conditions, the solid polymer is seen to have a structure not very different from that of the melt. This structure is stable at room temperature for long periods in the absence of moisture. However, on exposure to moisture, diffusion of water into the filament may result in elongation with accompanying changes in the crystalline character. The effects of temperature and moisture concentration on the diffusion process have been studied.X‐Ray diffraction, depolarisation of light and microscopical techniques have been used to examine the crystallisation process in the filament as it is being spun and during the subsequent process of equilibration with water.X‐Ray and optical results show changes of structure to occur on different time scales: the implications of this on the concepts of polymer morphology are discussed. The important röle played by atmospheric moisture in the crystallisation of 6.6 nylon is established, and the likely dependence on water content of second‐order transition data is

ISSN:0021-8871    

DOI:10.1002/jctb.5010140102

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThe expansion and changes in phase composition of dilute paste and mortar bars of normal and sulphate‐resisting Portland cement exposed to various sulphate solutions were studied over a period of time. Although strong expansion was usually associated with the presence of considerable amounts of calcium sulphoaluminate, there was no quantitative correlation between expansion and the concentration of crystalline calcium sulphoaluminate. Similar quantities of this compound were found in corresponding samples of normal and sulphate‐resisting cement. It was inferred that, on continued corrosion, calcium sulphoaluminate partially passes into a gel phase which may determine the properties of the cement.In the presence of magnesium ions the bars disintegrated before excessive expansion occurred, since these ions reacted with hydrating cement with the precipitation of magnesium hydroxide, which tends to block the pores and channels, thus preventing penetration of the solutions. Chloride ions increased expansion by forming calcium chloroaluminate. Under the static conditions of the experiments protective surface films develo

ISSN:0021-8871    

DOI:10.1002/jctb.5010140103

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractFilms of two air‐blown asphalts were exposed to the carbon arc at different intensities to determine the effect of radiant‐energy intensity on the rate of asphalt oxidation. The oxidation rates were established by measuring the changes in infra‐red absorption in the carbonyl band as a function of exposure time. It was found that: (a) the asphalt oxidation rate increased with the intensity of the carbon arc, (b) the radiant energy output of the accelerated weathering machine tends to level off at the higher voltage settings, and (c) at the maximum voltage adjustment switch setting of the accelerated weathering machine used, the incident‐radiant flux does not equal or exceed that which can be absorbed by

ISSN:0021-8871    

DOI:10.1002/jctb.5010140104

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThe variation in concentration of some constituents of tar in coke‐oven gas during the carbonising cycle has been investigated. The gas was sampled from the ascension pipe of the oven and examined by gas‐liquid chromatography for eleven hydrocarbons boiling in the range 180 to 340°. The concentrations of naphthalene and phenanthrene increased to maxima late in the cycle; those of methyl‐ and some dimethyl‐naphthalenes reached maxima early in t

ISSN:0021-8871    

DOI:10.1002/jctb.5010140105

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThe partition of thorium between nitric acid solutions and the solutions of some cyclohexyl‐ and benzyl‐alkylamines in benzene has been investigated at different concentrations of nitric acid and solvent, and at different temperatures. The extraction of nitric acid by these amines in benzene has also been examined. Further an infra‐red spectral study has been made of the organic solutions obtained. The mechanism of thorium extraction in this system is discussed on the basis of the results obt

ISSN:0021-8871    

DOI:10.1002/jctb.5010140106

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThe factors affecting the purity of crystal naphthalene recovered by the refrigeration of drained naphthalene oils have been studied by a statistically designed series of experiments on oils made up from pure compounds.The contaminants are shown to be of two types—intra‐crystalline and surface mother liquor. The former are principally those which form solid solutions with naphthalene. The quantity of mother liquor on the surface is related to crystal size, and the paraffinicity of the oil as indicated by its dens

ISSN:0021-8871    

DOI:10.1002/jctb.5010140107

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThe hydroperoxides in oxidised methyl oleate can be converted in high yield into the dinitro‐phenylhydrazones of aldehydes and aldehyde esters by reaction on a Celite/dinitrophenylhydrazine‐hydrochloric acid column. The aldehydes and aldehyde esters formed are the same as those produced during the thermal decomposition of methyl oleate hydroperoxide.The dinitrophenylhydrazones of unsaturated conjugated C18keto esters are also for

ISSN:0021-8871    

DOI:10.1002/jctb.5010140108

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY