The intrinsic viscosities of six fractions ( g , = 11.59.105 to 5.01-105) of poly(isobuty1 methacrylate) in seven solvents a t temperatures between 25 O C and 6OoC show the following order: chloroform > benzene > bromobenzene > dioxane > acrylonitrile > acetone > 2-hydroxymethyltetrahydrofuran. Values of a and k in the expression [q] = k Ma show little variations with temperature in the case of good solvents, whereas these variations are more pronounced in the case of poor solvents. For chloroform, the best solvent, the value of a was found to be 0.78, and for 2-hydroxymethyltetrahydrofuran a t 25OC the value of a is 0.56. The theta temperature for 2-hydroxymethyltetrahydrofuran is 19.5 f 0.3OC.
ZUSAMMENFASSUNG:Die Viskositatszahlen von sechs Fraktionen eines Poly(isobutylmethacry1ats) (gn = 11,59*105 bis 5,01.105) zwischen 25 und 6OoC in sieben Losungsmitteln weisen die nachstehende Reihenfolge auf: Chloroform > Benzol > Brombenzol > Dioxan > Acrylnitril > Aceton > 2-Hydroxymethyl-tetrahydrofuran. I n guten Losungsmitteln zeigen die in der Beiehung [q] = kMa auftretenden Werte a und k nur geringe kderungen mit der Temperatur, die sich jedoch in schlechten Losungsmitteln bemerkbar machen. I m Falle von Chloroform, dem besten Losungsmittel, ist a = 0,78; dagegen wird fiir 2-Hydroxymethyltetrahydrofuran bei 25OC fiir a = 0,56 gefunden. Die Thetatemperatur fur 2-Hydroxymethyl-tetrahydrofuran betragt 19,5 & 0,3OC.
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