Controlled coagulation and redispersion of thermoresponsive poly di(ethylene oxide) methyl ether methacrylate grafted cellulose nanocrystals.

Autor: Brinatti C; Institute of Chemistry - Universidade Estadual de Campinas (UNICAMP), CP 6154, CEP 13083-970 Campinas, SP, Brazil., Akhlaghi SP; Institute of Chemistry - Universidade Estadual de Campinas (UNICAMP), CP 6154, CEP 13083-970 Campinas, SP, Brazil., Pires-Oliveira R; Institute of Chemistry - Universidade Estadual de Campinas (UNICAMP), CP 6154, CEP 13083-970 Campinas, SP, Brazil., Bernardinelli OD; Institute of Chemistry - Universidade Estadual de Campinas (UNICAMP), CP 6154, CEP 13083-970 Campinas, SP, Brazil., Berry RM; CelluForce Inc., 625 Président-Kennedy Avenue, Montreal, Quebec H3A 1K2, Canada., Tam KC; Department of Chemical Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Ontario N2L 3G1, Canada., Loh W; Institute of Chemistry - Universidade Estadual de Campinas (UNICAMP), CP 6154, CEP 13083-970 Campinas, SP, Brazil. Electronic address: wloh@iqm.unicamp.br.
Jazyk: angličtina
Zdroj: Journal of colloid and interface science [J Colloid Interface Sci] 2019 Mar 07; Vol. 538, pp. 51-61. Date of Electronic Publication: 2018 Nov 17.
DOI: 10.1016/j.jcis.2018.11.071
Abstrakt: Hypothesis: Cellulose nanocrystals (CNCs) undergo precipitation in the presence of high concentrations of cationic surfactants in aqueous solutions. To avoid such behavior and/or to promote redispersion of CNC/surfactant mixtures, the CNC surface was grafted with poly di(ethylene oxide) methyl ether methacrylate, P(MEO 2 MA).
Experiments: CNC-g-P(MEO 2 MA) was characterized using the following techniques 13 C solid-state nuclear magnetic resonance ( 13 C SSNMR), Fourier-transform infrared spectroscopy - attenuated total reflection spectroscopy (FTIR-ATR) and thermal gravimetric analysis (TGA). Isothermal titration calorimetry (ITC), electrophoretic mobility, light scattering and high sensitivity differential scanning calorimetry (HSDSC) were used to study the interaction between CNC-g-P(MEO 2 MA) and ionic surfactants, dodecyltrimethylammonium bromide (C 12 TAB, cationic) and sodium dodecylsulfate (SDS, anionic) at temperatures below and above the LCST.
Findings: CNC-g-P(MEO 2 MA) underwent phase separation above its lower critical solution temperature (LCST ∼ 25 °C) and precipitated from solution as seen by HSDSC and transmittance experiments. When C 12 TAB was added to CNC-g-P(MEO 2 MA) it induced the precipitation that prevented the redispersion due to strong electrostatic interactions with the negative charges on the CNC surface. With increasing concentrations of SDS, the polymer phase transition temperature was increased, which can be used to redisperse the CNC complexes. By removing SDS from the mixture via dialysis, the CNC-g-P(MEO 2 MA) underwent subsequent phase transition.
(Copyright © 2018 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: