کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5184665 1381054 2009 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
New hydroxyproline based methacrylic polybetaines: Synthesis, pH sensitivity and catalytic activity
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
New hydroxyproline based methacrylic polybetaines: Synthesis, pH sensitivity and catalytic activity
چکیده انگلیسی

The synthesis of two new types of methacrylic polybetaines bearing trans-4-hydroxy-l-proline connected via its hydroxyl group is described, one with an aliphatic spacer of 6 carbon atoms and the other without any spacer. The pH sensitivity in aqueous media and the catalytic activity of the products in asymmetric aldol additions have been studied. The two polyzwitterions show an isoelectric point (IEP) close to 3. Swelling of networks prepared with the two monomers exhibit reversible pH sensitivity; the largest the pH distance from the IEP, the higher the net charge (positive or negative) and the higher the swelling. At basic pH and an ionic strength of 0.15, maximum swelling degrees of around 11 and 24 (g water/g polymer) have been found for the systems with and without spacer respectively. The polymers have been shown to be efficient catalysts for aldol reactions under homogeneous conditions in DMF but not in water.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 50, Issue 19, 10 September 2009, Pages 4438-4446
نویسندگان
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