engleski

Determination of Chemical Inhomogeneity of Transformation Products of Poly(vinyl chloride) by Extraction of Films from Aluminium Foil

The chemical transformation of poly(vinyl chloride) with toluene in 1, 2-dichloro-ethane as solvent has been carried out in the presence of aluminium bromide. A series of copolymer products of certain degrees of transformation has been prepared. The chemical and molecular inhomgeneity has been qualitatively investigated. The products have been fractionated by the Fuchs extraction method and refractionated by sucessive precipitation methods. The selectiv solvent systems have been predetermined. The benzene/methanol mixtures is selective for the separation of aromatic fractions in copolymer products with low transformation degree. The fractions whit noncyclisied aromatic units are separated whit a methyil ethyl ketone/methanol mixture. Chloroform/methanol succesfully selects aromatic fractions without vinyl chloride units in copolymer products of greater degree of transformation. The ratio of solvent/nonsolvent has been examined. The following fractions has been isolated: the farction of unreacted homopolymer PVC, the fraction with p-methyilstyrene units in chain, and the fraction of random copolymer with differences in the ratio of vinyl chloride, p-methylstyrene, and 5-methyl-1, 3-dimethyleneindan units. Characterization of the products and their fractions has been done on the basis of IR spectra, chlorine content, intinsic viscosity, and X-ray diffraction results. Analysis of IR spectra for PVC of low transformation degree in the region of C-Cl stretching vibrations indicates the presence of changes. The inclusion of coloured crystalline complexes of C6H5CH3*Al2Br6*HCl intermediate from the reaction, which is incorporated into the copolymer, has been notice.

chemical inhomogeneity; poly(vinyl chloride); extraction; aluminium foil

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