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An improved block osmometer used to determine the molecular weight distribution of commercial poly(vinyl chloride)
Author(s) -
Hayduk W.,
Kelly B. D.
Publication year - 1970
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1970.070140908
Subject(s) - osmometer , molar mass distribution , dispersity , chemistry , polymer , chromatography , molecular mass , vinyl chloride , mass fraction , capillary action , polyvinyl chloride , analytical chemistry (journal) , polymer chemistry , materials science , organic chemistry , copolymer , composite material , enzyme
Commercial PVC was fractionated into five fractions by the incremental addition of a nonsolvent to the polymer solution. The number‐average molecular weights of the original sample and fractions were determined by osmometry. The weight‐average molecular weights of the sample and fractions were also determined by means of viscosity measurements and by the application of a Mark‐Houwink type of equation. From a knowledge of the polydispersity of each fraction and the assumption that the number distribution of molecular weights was Gaussian, the molecular weight distribution for the composite sample was determined. The block osmometer used incorporated most of the features found useful in earlier work to facilitate rapid and reliable osmotic pressure measurements. In addition, microvolume‐regulating valves were utilized in the capillary tube lines to permit an independent precise positioning of the interface level in either capillary.