“Pillaring Effects” in Cross-Linked Cellulose Biopolymers: A Study of Structure and Properties

Abstract

Modified cellulose materials (CLE-4, CLE-1, and CLE-0.5) were prepared by cross-linking with epichlorohydrin (EP), where the products display variable structure, morphology, and thermal stability. Adsorptive probes such as nitrogen gas and phenolic dyes in aqueous solution reveal that cross-linked cellulose has greater accessible surface area (SA) than native cellulose. The results also reveal that the SA of cross-linked cellulose increased with greater EP content, except for CLE-0.5. The attenuation of SA for CLE-0.5 may relate to surface grafting onto cellulose beyond the stoichiometric cellulose and EP ratio since ca. 30% of the hydroxyl groups of cellulose are accessible for cross-linking reaction due to its tertiary fibril nature. Scanning electron microscopy (SEM) results reveal the variable surface roughness and fibre domains of cellulose due to cross-linking. X-ray diffraction (XRD) and 13C NMR spectroscopy indicate that cellulose adopts a one-chain triclinic unit cell structure (P1 space group) with gauche-trans (gt) and trans-gauche (tg) conformations of the glucosyl linkages and hydroxymethyl groups. The structural characterization results reveal that cross-linking of cellulose occurs at the amorphous domains. By contrast, the crystalline domains are preserved according to similar features in the XRD, FTIR, and 13C NMR spectra of cellulose and its cross-linked forms. This study contributes to an improved understanding of the role of cross-linking of native cellulose in its structure and functional properties. Cross-linked cellulose has variable surface functionality, structure, and textural properties that contribute significantly to their unique physicochemical properties over its native form.

Adsorption of Phosphate Dianions by Hybrid Inorganic–Biopolymer Polyelectrolyte Complexes: Experimental and Computational Studies

“…Thus, PEC formation between chitosan and alginate is inferred along with cross-linking with Al species for CAAL1. This results supports the pillaring of the biopolymer network and micropore domains upon formation of HIB-PECs. , …”

“…This results supports the pillaring of the biopolymer network and micropore domains upon formation of HIB-PECs. 43,54 3.1.7. X-ray Photoelectron Spectra (XPS).…”

Insoluble Regenerated Cellulose Films Made from Mildly Carboxylated Dissolving and Kraft Pulps

“…For the original pulps, peaks appeared at about 2θ = 17, 19, 26, and 40°representing (110), (11̅ 0), (200), and (040) crystallographic planes at 1.79 Å radiation wavelength, respectively. 26,27 The crystallinity indexes (CI) of the original kraft and dissolving pulps were 77 and 63%, while their apparent crystal sizes were measured 57 and 51 Å, respectively. For the films, a huge drop in the cellulose crystalline plane ( 200) is shown as well as a little shift of the peak due to the high dissolution of cellulose crystals.…”

New method for determining the degree of fibrillation of regenerated cellulose fibres

“…Furthermore, carboxylic acid-based crosslinkers such as citric acid and 1,2,3,4-butanetetra-carboxylic acid (BTCA) are thought to be sustainable approach for the crosslinking of cellulose (Yang et al 1997;Yao et al 2013;Aksoy and Genç 2015;Ye et al 2015;Liu et al 2016;Dhiman and Chakraborty 2017;Zhu and Liu 2018). Other researchers have also studied various sustainable or non-toxic crosslinkers to improve the quality of textiles, such as novel carboxylic acids (Maleic, Polymaleic and Succinic acid), phosphorus derivatives (phosphoric acid and Organophosphates), epichlorohydrin and silica derivatives (Yang et al 2010;Rojas and Azevedo 2011;Udoetok et al 2018).…”