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Revisiting the System Silanes–Polysaccharides: The Cases of THEOS–Chitosan and MeTHEOS–Chitosan
Author(s) -
BravoFlores Ileana,
MeléndezZamudio Miguel,
GuerraContreras Antonio,
RamírezOliva Eulalia,
ÁlvarezGuzmán Gilberto,
ZárragaNúñez Ramón,
Villegas Antonio,
Cervantes Jorge
Publication year - 2021
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.202000612
Subject(s) - chitosan , ethylene glycol , silane , silanes , polymer chemistry , chemistry , chemical modification , organic chemistry , solubility , materials science , chemical engineering , engineering
Abstract The glycol alkoxysilanes, tetrakis(2‐hydroxyethyl)silane (THEOS), and tris(2‐hydroxyethyl)methyl silane (MeTHEOS) are water soluble derivatives of tetraethoxysilane (TEOS) and methyltriethoxysilane (MeTEOS) and precursors of the system silane–chitosan reviewed in this work. The glycol modified alkoxysilanes are obtained by transesterification reaction of TEOS or MeTEOS with ethylene glycol. The reaction evolution is monitored by 29 Si NMR. It is possible to observe the formation of the various species of glycol alkoxysilanes in equilibrium as the reaction proceeds showing that the oligomers formation is favored at longer reaction times with the final product tendency to gel keeping the complete water solubility. The glycol alkoxysilanes are synthesized at moderated reaction conditions, by using the Piers–Rubinsztajn (PR) reaction. Additionally, it is already known that THEOS is compatible with different natural polysaccharides as chitosan and the same behavior has been demonstrated in this work for MeTHEOS. Several reports refer studies regarding the system THEOS–polysaccharides to synthesize hybrid materials. The system THEOS–chitosan is known but the characterization as well as the way silane–chitosan interact has not been studied in detail. In the present report, chemical evidence of the covalent interactions THEOS– and MeTHEOS–chitosan based on NMR studies ( 13 C and 29 Si) are presented as intended.