H. Kricheldorf, L. Vakhtangishvili, Gert Schwarz
Dec 15, 2005
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0
Influential Citations
17
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Journal
Journal of Polymer Science Part A
Abstract
1,1,1-Tris(4-trimethylsiloxyphenyl)ethane, (silylated THPE), was polycondensed with 2,4-difluoroacetophenone and 2,4-difluorobenzophenone. All polycondensations were performed in N-methylpyrrolidone with K2CO3 as promotor. The feed ratio THPE/difluoroaromat was varied from 1.0:1.3 to 1.0:1.5. Instead of hyperbranched polymers or gels, soluble multicyclic oligo- and polyethers were identified as main reaction products by MALDI-TOF mass spectrometry in all experiments. At feed ratios around 1.0:1.5 multicycles free of functional group were the main products. However, when isomeric a2-monomers such as 2,6-difluoroacetophenone, 2,6-difluorobenzophenone (or 2,6-difluorodiphenylsulfone) were used, gelation occurred at feed ratios as low as 1.0:1.1. An explanation of the different cyclization tendencies on the basis of different conformations is discussed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6233–6246, 2005