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An Apparatus for Automated Turbidity Titrations and Its Application to Copolymer Analysis and to the Determination of Phase Diagrams
Author(s) -
Schneider Anja,
Wünsch Matthias,
Wolf Bernhard A.
Publication year - 2002
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20020301)203:4<705::aid-macp705>3.0.co;2-7
Subject(s) - copolymer , titration , polydimethylsiloxane , phase (matter) , vinyl acetate , vinyl alcohol , toluene , polymer chemistry , turbidity , analytical chemistry (journal) , chemistry , phase diagram , materials science , chemical engineering , chromatography , organic chemistry , polymer , oceanography , engineering , geology
We present an apparatus for quick and reliable determinations of transmission curves specifying the dependence of the light intensity (normalized to that of the primary beam) passing a test solution on the amount of standard solution added. This device is used for two different purposes, namely for the analysis of copolymers (here: poly(vinyl alcohol), which is a copolymer since it is produced via incomplete hydrolysis of poly(vinyl acetate)) and for the determination of phase diagrams (here: toluene/ethanol/polydimethylsiloxane). The most important observation in the field of copolymer analysis consists in the possibility to obtain information on the widths of the chemical distribution. Adequate turbidimetric titrations reveal pronounced differences between samples that should according to their standard characterization with respect to average chain length and average chemical composition be identical. The central message regarding phase diagrams is that the evaluation of transmission curves with respect to macroscopic demixing is greatly simplified by the fact that the phase separation of a given system takes place within a small band of transmission values, independent of the composition of the mixture.