ISSN:
0022-3832
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
Ceiling temperatures Tc (at which the free energy change for the reaction is zero) have been determined for the formation of polysulfones from a wide variety of olefins and allyl compounds under standard concentration conditions ([M] [S] = 27 mole2 liter-2, M = unsaturated compound, S = sulfur dioxide). In the 1-olefin series Tc falls from ethylene to propylene 90°, to 1-butene 64°, and then remains approximate constant as the chain is lengthened. With 2-olefins there is a progressive decrease from butene 34°, to pentene 8°, to heptene -38°. Branching invariably lowers Tc and the effect is greatest when the branching is at the double bond; thus isobutene 4°, 3-methyl-1-butene 36°, 4,4-dimethyl-1-pentene 14°. 2-ethyl substitution of a 1-olefin, or 2, 3, or 4 branching of a 2-olefin results in inability to react (Tc 〈 -80°). Cycloolefins have Tc values considerably higher than the corresponding 2-olefins; thus cyclopentene 102°, cyclohexene 24°. In the allyl compounds a carboxyl group tends to lower Tc but a hydroxyl group raises Tc. An ether group raises Tc slightly. The results are discussed in terms of structural effects on the heat and entropy changes and on the monomer activity coefficients and polymer solubilities. The infrared absorption spectra of 20 polysulfones and 3 aliphatic sulfones are recorded for the sulfone stretching region (7.5-9.5 μ).
Zusätzliches Material:
2 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pol.1957.1202611410
Permalink
