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Polymers 2012, 4(1), 396-407; doi:10.3390/polym4010396
Article

Degree of Branching in Hyperbranched Poly(glycerol-co-diacid)s Synthesized in Toluene

*  and
United States Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, USA
* Author to whom correspondence should be addressed.
Received: 1 January 2012 / Revised: 28 January 2012 / Accepted: 31 January 2012 / Published: 6 February 2012
(This article belongs to the Special Issue Dendrimers and Hyperbranched Polymers)
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Abstract

1H NMR and 13C NMR spectrometry (1-dimensional and 2-dimensional) have been used to assign chemical resonances and determine the degrees of branching for polyesters synthesized by the Lewis acid (dibutyltin(IV)oxide)-catalyzed polycondensation of glycerol with either succinic acid (n (aliphatic chain length) = 2), glutaric acid (n = 3) or azelaic acid (n = 7) in quasi-melt solutions with toluene. When 1:1 and 2:1 (diacid:glycerol) molar ratios were used, it was found that the glutaric acid-derived polymers gave the highest degree of polymer branching (31.2%, 85.6%, respectively) after the 24 h reaction period followed by the succinic acid-derived polymers (39.4%, 41.9%, respectively) and the azelaic acid-derived polymers (9.9%, 13.9%, respectively). Reactions performed at reflux for 24 h resulted in a 70.8% and 56.7% decrease in degree of branching for succinic acid and glutaric acid-derived polyesters, respectively. There is no indication that degree of branching is significantly affected by the presence or absence of solvent according to the results obtained in this research.
Keywords: diacids; hyper-branching; glycerol; polymers diacids; hyper-branching; glycerol; polymers
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Wyatt, V.T.; Strahan, G.D. Degree of Branching in Hyperbranched Poly(glycerol-co-diacid)s Synthesized in Toluene. Polymers 2012, 4, 396-407.

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