Synthesis and Characterization of Stiff, Self-Crosslinked Thermoresponsive DMAA Hydrogels
Stiff thermosensitive hydrogels (HG) were synthesized by self-crosslinking free radical polymerization of <i>N,N</i>-dimethylacrylamide (DMAA) and N-isopropylacrylamide (NIPAAm), adjusting the degree of swelling by carboxylate-containing sodium acrylate (NaAc) or a 2-oxazoline macromonom...
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doaj-7f07d1adb0ad4954b7a00acc6d110b842020-11-25T03:06:35ZengMDPI AGPolymers2073-43602020-06-01121401140110.3390/polym12061401Synthesis and Characterization of Stiff, Self-Crosslinked Thermoresponsive DMAA HydrogelsJuan Carlos Rueda0Fátima Santillán1Hartmut Komber2Brigitte Voit3Polymer Laboratory, Physics Section, Research Department (DGI), Pontifical Catholic University of Peru (PUCP), San Miguel 15088, PeruPolymer Laboratory, Physics Section, Research Department (DGI), Pontifical Catholic University of Peru (PUCP), San Miguel 15088, PeruLeibniz Institute of Polymer Research Dresden, Hohe Strasse 6, 01069 Dresden, GermanyLeibniz Institute of Polymer Research Dresden, Hohe Strasse 6, 01069 Dresden, GermanyStiff thermosensitive hydrogels (HG) were synthesized by self-crosslinking free radical polymerization of <i>N,N</i>-dimethylacrylamide (DMAA) and N-isopropylacrylamide (NIPAAm), adjusting the degree of swelling by carboxylate-containing sodium acrylate (NaAc) or a 2-oxazoline macromonomer (MM). The formation of hydrogels was possible due to the self-crosslinking property of DMAA when polymerized with peroxodisulfate initiator type. The MM was synthetized by the ring-opening cationic polymerization of 2-methyl-2-oxazoline (MeOxa) and methyl-3-(oxazol-2-yl)-propionate (EsterOxa), and contained a polymerizable styryl endgroup. After ester hydrolysis of EsterOxa units, a carboxylate-containing MM was obtained. The structure of the hydrogels was confirmed by <sup>1</sup>H high-resolution (HR)-MAS NMR spectroscopy. Suitable conditions and compositions of the comonomers have been found, which allowed efficient self-crosslinking as well as a thermoresponsive swelling in water. Incorporation of both the polar comonomer and the macromonomer, in small amounts furthermore allowed the adjustment of the degree of swelling. However, the macromonomer was better suited to retain the thermoresponsive behavior of the poly (NIPAAm) due to a phase separation of the tangling polyoxazoline side chains. Thermogravimetric analysis determined that the hydrogels were stable up to ~ 350 °C, and dynamic mechanical analysis characterized a viscoelastic behavior of the hydrogels, properties that are required, for example, for possible use as an actuator material.https://www.mdpi.com/2073-4360/12/6/1401DMAA hydrogelthermosensitivityself-crosslinkingmacromondomerpolyoxazoline |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Juan Carlos Rueda Fátima Santillán Hartmut Komber Brigitte Voit |
spellingShingle |
Juan Carlos Rueda Fátima Santillán Hartmut Komber Brigitte Voit Synthesis and Characterization of Stiff, Self-Crosslinked Thermoresponsive DMAA Hydrogels Polymers DMAA hydrogel thermosensitivity self-crosslinking macromondomer polyoxazoline |
author_facet |
Juan Carlos Rueda Fátima Santillán Hartmut Komber Brigitte Voit |
author_sort |
Juan Carlos Rueda |
title |
Synthesis and Characterization of Stiff, Self-Crosslinked Thermoresponsive DMAA Hydrogels |
title_short |
Synthesis and Characterization of Stiff, Self-Crosslinked Thermoresponsive DMAA Hydrogels |
title_full |
Synthesis and Characterization of Stiff, Self-Crosslinked Thermoresponsive DMAA Hydrogels |
title_fullStr |
Synthesis and Characterization of Stiff, Self-Crosslinked Thermoresponsive DMAA Hydrogels |
title_full_unstemmed |
Synthesis and Characterization of Stiff, Self-Crosslinked Thermoresponsive DMAA Hydrogels |
title_sort |
synthesis and characterization of stiff, self-crosslinked thermoresponsive dmaa hydrogels |
publisher |
MDPI AG |
series |
Polymers |
issn |
2073-4360 |
publishDate |
2020-06-01 |
description |
Stiff thermosensitive hydrogels (HG) were synthesized by self-crosslinking free radical polymerization of <i>N,N</i>-dimethylacrylamide (DMAA) and N-isopropylacrylamide (NIPAAm), adjusting the degree of swelling by carboxylate-containing sodium acrylate (NaAc) or a 2-oxazoline macromonomer (MM). The formation of hydrogels was possible due to the self-crosslinking property of DMAA when polymerized with peroxodisulfate initiator type. The MM was synthetized by the ring-opening cationic polymerization of 2-methyl-2-oxazoline (MeOxa) and methyl-3-(oxazol-2-yl)-propionate (EsterOxa), and contained a polymerizable styryl endgroup. After ester hydrolysis of EsterOxa units, a carboxylate-containing MM was obtained. The structure of the hydrogels was confirmed by <sup>1</sup>H high-resolution (HR)-MAS NMR spectroscopy. Suitable conditions and compositions of the comonomers have been found, which allowed efficient self-crosslinking as well as a thermoresponsive swelling in water. Incorporation of both the polar comonomer and the macromonomer, in small amounts furthermore allowed the adjustment of the degree of swelling. However, the macromonomer was better suited to retain the thermoresponsive behavior of the poly (NIPAAm) due to a phase separation of the tangling polyoxazoline side chains. Thermogravimetric analysis determined that the hydrogels were stable up to ~ 350 °C, and dynamic mechanical analysis characterized a viscoelastic behavior of the hydrogels, properties that are required, for example, for possible use as an actuator material. |
topic |
DMAA hydrogel thermosensitivity self-crosslinking macromondomer polyoxazoline |
url |
https://www.mdpi.com/2073-4360/12/6/1401 |
work_keys_str_mv |
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1724673534000627712 |