Photoresponsive polyamides containing pentamethylated norbornadiene moieties: Synthesis and photochemical properties under sunlight irradiation |
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Authors: | Ahmed Oueslati Imen Abdelhedi Régis Mercier Eric Drockenmuller Hatem Ben Romdhane |
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Institution: | 1. Université de Tunis El Manar, Faculté des Sciences de Tunis, Laboratoire de Chimie Organique Structurale et Macromoléculaire (LR99ES14), , 2092 El Manar, Tunisie;2. Université Claude Bernard Lyon 1, Ingénierie des Matériaux Polymères (IMP – UMR CNRS 5223), , 69622 Villeurbanne Cedex, France |
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Abstract: | Photoresponsive polyamides containing main‐chain pentamethylated norbornadiene (NBD) moieties are obtained in quantitative yields via the Yamazaki–Higashi reaction between a pentamethylated NBD dicarboxylic acid and a series of aromatic diamines. Chemical structures are confirmed by 1H and 13C NMR and weight average molar masses measured by SEC are in the range of 21,500–28,600 g mol?1 with chain dispersities close to 2. Physical properties are investigated by FTIR, differential scanning calorimetry (DSC), thermogravimetric analysis, and viscosimetry. All obtained polyamides are amorphous with glass transition temperatures ranging from 68 to 124 °C. They are soluble at room temperature in common organic solvents and exhibit good thermal stabilities with Td10 values ranging from 175 to 276 °C. The photochemical isomerization of the NBD moiety into quadricyclane (QC) is studied by UV/vis spectroscopy after sunlight irradiation of polymer films. For all polyamides, a first‐order kinetic rate is observed for the conversion of NBD to QC. The thermal release of the stored energy associated to the reverse transformation of QC groups into NBD ones is about 90–95 kJ mol?1 as measured by DSC of the irradiated polymer films. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4650–4656 |
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Keywords: | irradiation isomer/isomerization polyamides step‐growth polymerization stimuli‐sensitive polymers UV– vis spectroscopy |
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