| Literature DB >> 35209224 |
Hamid M Shaikh1, Arfat Anis1, Anesh Manjaly Poulose1, Saeed M Al-Zahrani1, Niyaz Ahamad Madhar2, Abdullah Alhamidi1, Saleh Husam Aldeligan1, Faisal S Alsubaie1.
Abstract
Cellulosic polysaccharides have increasingly been recognized as a viable substitute for the depleting petro-based feedstock due to numerous modification options for obtaining a plethora of bio-based materials. In this study, cellulose triacetate was synthesized from pure cellulose obtained from the waste lignocellulosic part of date palm (Phoenix dactylifera L.). To achieve a degree of substitution (DS) of the hydroxyl group of 2.9, a heterogeneous acetylation reaction was carried out with acetic anhydride as an acetyl donor. The obtained cellulose ester was compared with a commercially available derivative and characterized using various analytical methods. This cellulose triacetate contains approximately 43.9% acetyl and has a molecular weight of 205,102 g·mol-1. The maximum thermal decomposition temperature of acetate was found to be 380 °C, similar to that of a reference sample. Thus, the synthesized ester derivate can be suitable for fabricating biodegradable and "all cellulose" biocomposite systems.Entities:
Keywords: acetylation; cellulose; cellulose triacetate; date palm mesh; degree of substitution; thermal stability
Mesh:
Substances:
Year: 2022 PMID: 35209224 PMCID: PMC8879401 DOI: 10.3390/molecules27041434
Source DB: PubMed Journal: Molecules ISSN: 1420-3049 Impact factor: 4.411
Figure 1FTIR spectra of cellulose triacetate (CTA) samples.
Characteristic peak assignment of cellulose and cellulose triacetate. Adapted with permission from Ref. [23,24]. Copyright 2002 and 2004 Elsevier. Ref. [25]. Copyright 2015 American Chemical Society.
| Functional Group Assignments | Wavenumber, cm−1 | ||
|---|---|---|---|
| Cellulose | CTA-1 | CTA-2 | |
| νOH (covalent bond, hydrogen bonding) | 3335 | -- | -- |
| νCH | 2897 | 2940 | 2952 |
| C=O stretching of the acetyl group | -- | 1740 | 1732 |
| H2O absorbed (absorbed water hydrogen-bonded)) | 1645 | 1635 | 1640 |
| δCH2 ((symmetric) at C-6; crystalline region) | 1430 | 1430 | 1425 |
| C–H bending vibration of CH3 in the acetyl group) | -- | 1369 | 1365 |
| δCH2 (wagging at C-6) Or δCOH in a plane at C-2 and C-3 | 1320 | 1319 | 1322 |
| δCOH in a plane at C-6 | 1253 | -- | -- |
| C–O stretching of the acetyl group | -- | 1222 | 1215 |
| νCO, δOH (γCOC at β-glycosidic linkage) | 1160 | 1168 | 1164 |
| γ-ring in plane | 1103 | 1122 | 1125 |
| νC-O (c-o-c of the cellulose backbone) | 1052 | 1037 | 1040 |
| γ-CO at C-6 | 1029 | 952 | 1010 |
| δCH2 (γCOC at β-glycosidic linkage; amorphous region) | 898 | 899 | 902 |
Figure 213C-NMR spectral characteristics of the CTA sample.
Figure 313C-NMR spectral characteristics of the CTA sample.
Carbon signal positions of cellulose acetate samples. Reprinted/Adapted with permission from Ref. [14]. Copyright 2014 John Wiley and Sons. Ref. [26]. Copyright 2013 Elsevier.
| Sample | C7 = O (ppm) | C1 (ppm) | C4 (ppm) | C3 (ppm) | C5 (ppm) | C2 (ppm) | C6 (ppm) | C8 (ppm) |
|---|---|---|---|---|---|---|---|---|
| CTA-1 | 170.3 (C6) * | 100.6 | 76.2 | 71.9 | 72.9 | 71.9 | 62.1 | 20.9 (C6) $ |
| 169.8 (C3) * | 20.6 (C3) $ | |||||||
| 169.4 (C2) * | 20.5 (C2) $ | |||||||
| CTA-2 | 170.3 (C6) * | 100.6 | 76.2 | 71.9 | 72.9 | 71.9 | 62.2 | 20.9 (C6) $ |
| 169.9 (C3) * | 20.7 (C3) $ | |||||||
| 169.4 (C2) * | 20.6 (C2) $ |
* C7 is bonded to C6, C3, and C2.; $ C2, C3 and C6 bonded to C8.
Figure 4XRD diffractograms of cellulose, CTA-1 and CTA-2.
Figure 5Thermogravimetric (TGA) and differential thermogravimetric (DTG) analysis of cellulose acetate samples.
Figure 6SEM images of (a) cellulose, (b) CTA-1 and (c) CTA-2.
Characteristics of CTA samples.
| Sample | %Acetyl | DS | %Yield | Average Mol. Wt. (Mw) | Tensile Strength (MPa) |
|---|---|---|---|---|---|
| CTA-1 | 44.44 | 2.91 | - | 222,168.60 | 27 |
| CTA-2 | 43.51 | 2.85 | 94.5 | 205,102.25 | 22 |