@article{10272/8750,
year = {2014},
url = {http://hdl.handle.net/10272/8750},
abstract = {This work deals with the influence of functionalization degree on the
thermogravimetric and rheological behaviour of NCO-functionalized chitosan- and
chitin-based oleogels. Chitosan and chitin were functionalized using different proportions
of 1,6-hexamethylene diisocyanate (HMDI) and subsequently dispersed in castor oil to
promote the chemical reaction between the –NCO group of the modified biopolymer and
the –OH group located in the ricinoleic fatty acid chain of castor oil, thus resulting in
different oleogels with specific thermogravimetric and rheological characteristics.
Biopolymers and oleogels were characterized through Fourier transform infrared
spectroscopy (FTIR) and thermogravimetric analysis (TGA). Small-amplitude oscillatory
shear (SAOS) measurements were performed on the oleogels. Oleogels presented suitable
thermal resistance, despite the fact that the inclusion of HMDI moieties in the polymer
structure led to a reduction in the onset temperature of thermal degradation. The insertion
of low amounts of HMDI in both chitin and chitosan produces a drastic reduction in the
values of oleogel viscoelastic functions but, above a critical threshold, they increase with the functionalization degree so that isocyanate functionalization results in a chemical tool
to modulate oleogel rheological response. Several NCO-functionalized chitosan- and
chitin-based oleogel formulations present suitable thermal resistance and rheological
characteristics to be proposed as bio-based alternatives to traditional lubricating greases.},
organization = {This work is part of two research projects (CTQ2010-15338 and TEP-1499) sponsored by MINECO-FEDER (70% European cofunding rate) and Junta de Andalucia programmes, respectively. One of the authors (Rocio Gallego) has received a Ph.D. Research Grant from DIGICyT (MINECO). The authors gratefully acknowledge the financial support.},
publisher = {MDPI},
title = {Influence of functionalization degree on the rheological properties of isocyanate-functionalized chitin- and chitosan-based chemical oleogels for lubricant applications},
doi = {10.3390/polym6071929},
author = {Gallego Calvo, Rocío and González, Mercedes and Fernández Arteaga, Jesús and Valencia Barragán, Concepción and Franco Gómez, José María},
}