tempo and stearylamine

The enzymatic functionalization of lignocellulosic fibers using oxidoreductases was successfully achieved by targeting lignin moieties as grafting sites on the surface. In this study, a novel strategy for hydrophobization of lignocelluloses was investigated, which involved the laccase/TEMPO-mediated grafting of octadecylamine (OA) onto both lignin and cellulose components of jute fabrics. The results showed that OA monomers were successfully grafted onto jute fabric surface using the laccase/TEMPO system with the grafting percentage and efficiency values of 0.712% and 10.571%, respectively. The primary hydroxyl groups of cellulose were oxidized by laccase/TEMPO to carbonyl groups, which were then coupled with amino-contained OA monomers via Schiff base reaction. The phenolic hydroxyl groups of lignin were transformed by laccase to radicals, on which OA molecules were grafted via Michael addition reaction. Consequently, grafted jute fabrics showed a considerable increase in the surface hydrophobicity with a contact angle of 125.9° and a wetting time of at least 2 h. Furthermore, there was an acceptable decrease in the breaking strength of jute fabrics by 13.60%, and the color of fabrics turned yellowish and reddish. This eco-friendly enzymatic process provides a new strategy for grafting hydrophobization and even functionalization of lignocellulosic fiber materials using amino compounds.

Topics: Amines; Cellulose; Cyclic N-Oxides; Dietary Fiber; Hydrophobic and Hydrophilic Interactions; Laccase; Lignin

Hydrophobic cotton fabrics were prepared by grafting octadecylamine (ODA) onto cotton fiber surfaces via the laccase/2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) treatment. The cotton fibers were oxidized by laccase/TEMPO to introduce aldehyde groups, which reacted with the amino groups of ODA to form Schiff base. First, ODA was coupled to glucan, used as a model compound of cellulose. The results of FT-IR and MALDI-TOF mass spectroscopy prove the formation of a Schiff base between ODA and glucan. Moreover, the existence of ODA in the grafted cotton fibers was verified by ATR-FTIR, elemental analysis, X-ray photoelectron spectroscopy. Finally, the hydrophobicity of the ODA-grafted cotton fabrics was estimated. The surface hydrophobicity of the cotton fabrics increased after the enzymatic grafting reaction.

Topics: Amines; Cotton Fiber; Cyclic N-Oxides; Hydrophobic and Hydrophilic Interactions; Laccase; Schiff Bases