@Article{jrm.2023.027651,
AUTHOR = {Elham Azadeh, Antonio Pizzi, Christine Gerardin-Charbonnier, Philippe Gerardin},
TITLE = {Hydrolysable Chestnut Tannin Extract Chemical Complexity in Its  Reactions for Non-Isocyanate Polyurethanes (NIPU) Foams},
JOURNAL = {Journal of Renewable Materials},
VOLUME = {11},
YEAR = {2023},
NUMBER = {6},
PAGES = {2823--2848},
URL = {http://www.techscience.com/jrm/v11n6/52255},
ISSN = {2164-6341},
ABSTRACT = {Non-isocyanate polyurethane (NIPU) foams from a commercial hydrolysable tannin extract, chestnut wood 
tannin extract, have been prepared to determine what chemical species and products are taking part in the 
reactions involved. This method is based on two main steps: the reaction with dimethyl carbonate and the 
formation of urethane bonds by further reaction of the carbonated tannin with a diamine-like hexamethylene 
diamine. The hydroxyl groups on the tannin polyphenols and on the carbohydrates intimately linked with it 
and part of a hydrolysable tannin are the groups involved in these reactions. The carbohydrate skeleton of the 
hydrolysable tannin is also able to participate through its hydroxyl groups to the same two reactions rendering 
the whole molecular complex able to react to form NIPUs. The analysis by Matrix-Assisted Laser Desorption 
Ionization (MALDI-TOF) mass spectrometry and <sup>13</sup>C Nuclear Magnetic Resonance (<sup>13</sup>C NMR) to further 
investigate the reaction mechanisms involved revealed the unsuspected complexity of chestnut hydrolysable 
tannin, with different fragments reacting in different manners forming a hardened network of considerable 
complexity. As the morphology and performance of these types of foams changes slightly with the change in 
the amount of glutaraldehyde and hexamine hardeners, the best performing foam formulation previously 
determined was scanned by SEM and analysed chemically for the structures formed.},
DOI = {10.32604/jrm.2023.027651}
}