Chromatographic fractionation—I. Modified columns for the fractionation of polymers

974

Abstracts

These Compounds are soluble in non-polar and Weakly polar solvents a n d do not melt at, temperatures up to 500 °. Polyphenylferrosiloxanes are highly thermostable a n d of low volatility at temperatures 200-320 ° . CHROMATOGRAPHIC FRACTIONATION--I. TIONATION OF POLYMERS

O. G. T a r a k a n o v 1962.

MODIFIED COLUMNS FOR THE FRAC-

a n d P . A. O k u n e v , V y s o k o m o l .

s o e d i n . 4: N o . 5, 6 8 3 - 6 8 9 ,

A MODIFIED chromatographic column is described for fractionating polymers. A unit for the preliminary fractionation of the substance undergoing investigation has been incorporated into the scheme of the column. Two diagrams of the columns have been presented. Cellulose triacetate has been investigated with the aid of this method. Methylene chloride-heptane with constantly increasing methylene chloride content served as eluent. The fractionation lasted a b o u t 4 days and the number of fractions numbered 20-30. T E M P E R A T U R E CHANGES IN THE ESR SPECTRA OF ALLYL AND OTHER RADICALS IN I R R A D I A T E D POLYMERS

Y u . N . M o l i n , A:. T. K o r i t s k i i , V. N . S h a m s h e v a n d N. Y a . B u b e n , V y s o k o m o l . s o e d i n . 4: N o . 5, 6 9 0 - 6 9 5 , 1962. THE reversible temperature dependence of the E S R spectrum of the allyl radical in isotropic and oriented specimens of low pressure polyethylene has been inves¢,i~ated. Ha,

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H& H~ H ~ H ~ HB~ I n the analysis of the isotropic specimen spectra it has been taken into account t h a t the isotropic broadening of the hyperfine structure components depends u p o n the mutual spir~ orientations of the a-protons. The reversible change in the spectra has been explained b y a violation of the equivalency of the fl-protons in the allyl radical of lowering the temperature. I t has been suggested t h a t this violation is due to distortion of the geometric structure of the radical under the influence of the crystal lattice of the polymer. Reversible changes in the E S R spectra have also been discovered in irradiated capron and nylon• EFFECT OF STRUCTURATION OF ELASTOMERS ON THEIR ADHESION TO F I B R E FORMING P O L Y M E R S - - I H . EFFECT OF T H E TYPE OF VULCANIZATION OF RUBBERS ON T H E CHANGE IN STRENGTH OF THE ADHESION BOND

V. G. R a y e r s k i , S. S. V o y u t s k i i a n d I . V. L i v a n o v a , V y s o k o m o l . s o e d i n . 4: N o . 5, 6 9 6 - 7 0 1 , 1962. T~IE change in strength of the adhesion b o n d of rubber to some fibre+forming polymers in the process of vulcanization in the presence of tetramethylthiuramdisulphide (thiuram) as compared with sulphur has been investigated on the example of sodium-butadiene rubber (with thiuram alone) a n d polyehloroprcne rubber in the additional presence of zinc and magnesium oxides. I t has been shown t h a t thiuram does not change the nature of the relation