ISSN:
0025-116X
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
Poly(epichlorohydrin) and poly(epichlorohydrin-co-ethylene oxide) were modified by reaction with potassium thiocyanate (KSCN), tetrabutylammonium p-toluenesulfinate (NBu4SO2C7H7) and tetrabutylammonium benzenesulfinate (NBu4SO2C6H5). Though the substitution of chlorine in the polymers with these nucleophilic reagents in most cases is accompanied by side reactions, appropriate reaction conditions allow degrees of substitution higher than 90% to be obtained. The glass transition temperature (Tg) of the thiocyanate-modified homo- and copolymer exhibits only a small increase with increasing degree of substitution. While the Tg of the original homo- and copolymer is observed at -20°C and -38°C, respectively, the glass transition of the highly substituted homopolymer occurs at -12°C and for the copolymer at -31°C. On the other hand, the thiocyanate-modified polymers show a remarkably higher decomposition temperature of about 250°C as compared with that of the unmodified polymers (160-180°C). In addition, the solubility is markedly influenced by the substitution. While the original homo- and copolymers are soluble in, e.g., benzene and toluene, the highly modified products are only soluble in polar solvents such as THF, acetone, DMSO and diglyme. Introducing sulfonyl groups, the resulting polymers exhibit a glass transition temperature increased to a greater extent. For the homopolymer with the highest degree of substitution (98,3%), a Tg of 73°C is observed. Concerning the decomposition temperature, a drastical increase up to 370°C occurs. Finally the influence of phase transfer catalysts on the described reactions was investigated.
Zusätzliches Material:
7 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/macp.1992.021930503
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