Investigation of Thermal Behavior of Layered Double Hydroxides Intercalated with Carboxymethylcellulose Aiming Bio-Carbon Based Nanocomposites

Abstract

Carboxymethylcellulose (CMC), a polymer derived from biomass, was intercalated into layered double hydroxides (LDH) composed by M2+/Al3+ (M2Al-CMC, M = Mg or Zn) and evaluated as precursors for the preparation of biocarbon-based nanocomposites by pyrolysis. M2Al-CMC hybrids were obtained by coprecipitation and characterized by X ray diffraction (XRD), vibrational spectroscopies, chemical analysis, and thermal analysis coupled to mass spectrometry. Following, pyrolyzed materials obtained between 500–1000 °C were characterized by XRD, Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Above 600 °C, Raman spectra of all samples showed the presence of graphitic carbon, which plays a role in the degree of crystallinity of produced inorganic phases (for comparison purposes, M2Al-CO3 materials were investigated after calcination in the same experimental conditions). XRD patterns of Mg2Al-CMC pyrolyzed between 600–1000 °C showed poorly crystallized MgO and absence of spinel reflections, whereas for Zn2Al-CMC, it was observed well crystallized nanometric ZnO at 800 °C, and ZnAl2O4 and γ-Al2O3 phases at 1000 °C. Above 800 °C, the carbothermic reaction was noticed, transforming ZnO to zinc vapour. This study opens perspectives for nanocomposites preparation based on carbon and inorganic (mixed) oxides through precursors having organic-inorganic interactions at the nanoscale domain.

Mixed Metal Oxide by Calcination of Layered Double Hydroxide: Parameters Affecting Specific Surface Area

“…Similar to MgAl-LDH, thermal treatment on ZnAl-LDH caused the partial collapse in lamellar structure through degassing. Calcination at moderate temperature from 300 °C to 600 °C resulted in divalent metal oxide (ZnO) [ 62 , 63 , 64 ]. Different from MgAl-MMO, however, the ZnAl-MMO tends to have lower specific surface area ( Figure 1 (Ab)).…”

Enhancement of the Supercapacitive Performance of Cobalt-tin-cyanate Layered Structures through Conversion from 2D Materials to 1D Nanofibers

“…The TGA curve shows the total wei loss that occurred throughout the two stages. In the first stage, the water was lost through three steps [38]. It was found that wt.%, 7 wt.% and 8.3 wt.% were lost at 107 °C, 150 °C and 191 °C, respectively.…”

“…Additionally, DTA revealed two endotherm peaks at 250.6 °C and 307.9 °C, confirming the presence of two interlayered anions, c nate and nitrate, agreeing with the FTIR data. In the first stage, the water was lost through three steps [38]. It was found that 4.6 wt.%, 7 wt.% and 8.…”

Thermal behavior and antibacterial studies of a carbonate Mg–Al-based layered double hydroxide (LDH) for in vivo uses

“…Since Mg-Al-based LDHs also find use in drug delivery and biomedical imaging [9,11], the knowledge of the antibacterial activity seems to assume, like for bioactive glasses [12,13], a crucial importance and needs to be further investigated. On the other hand, some of these LDHs may intercalate suitable molecules and a thermal treatment of the so-obtained precursor materials may convert them into very promising oxides or composites [14,15]. The thermal activation of a LDH by calcination in a wide temperature range that usually is between 300 and 500 °C causes the release of water due to condensation of hydroxyl groups resulting in the formation a mixed metal oxides [16,17].…”