Attaching of flexible chains to novolacs on the basis of bisphenol A
β Scribed by Veronika Strehmel; Hendrik Wetzel; Bernd Strehmel
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 819 KB
- Volume
- 60
- Category
- Article
- ISSN
- 0021-8995
No coin nor oath required. For personal study only.
β¦ Synopsis
Networks containing both flexible segments and rigid structures were synthesized on the basis of bisphenol A novolacs and diglycidylether of butanediol using imidazole as an accelerator. A stoichiometric ratio between epoxy groups and phenolic groups of the novolacs leads to networks with methylene bridges as network junctions. In contrast to this, the same reaction with bisphenol A leads to completely soluble products. The glass transition temperature of this soluble material is considerably lower than the glass transition temperature of the networks. Increasing content of methylene bridges in the novolacs leads to a n increase of the glass transition temperature of the networks and to a decrease of the Acp value at the glass transition. Furthermore, epoxy excess leads to networks with rubberlike properties. In addition, AM1 calculation were performed to optimize the geometric structure of the bisphenol A novolac used in the reaction with the diglycidylether. It was found that conformations with intramolecular hydrogen bondings exist between phenolic hydroxyl groups, which considerably influence the reactivity of the novolac with the epoxy group.
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## Abstract Polysarcosine having sulfhydryl groups attached to both ends was synthesized by the NCA method and its airβoxidation was investigated in aqueous solution with cupricβion or ferricβion catalysts. Airβoxidation was also conducted for a polysarcosine having one terminal sulfhydryl group. T
## Abstract Chains that are unperturbed by the intramolecular excluded volume effect are examined in the free state and under conditions where one of the ends is attached to an impenetrable surface. The density of the attachment of the chains to the surface is so low that interchain interactions ca