Functionalisation of cellulosic substrates by a facile solventless method of introducing carbamate groups

A facile method for the introduction of carbamate groups in cellulosic substrates is described. Woven cellulosic fabrics were padded with non-alkali treatment solutions containing PEG 2000, urea, and LiCl and heated at elevated temperatures to obtain cellulose carbamate fabrics. The introduction of carbamate groups was confirmed with FTIR-ATR and NMR spectroscopy, and the treated fabrics exhibited nitrogen contents of 0.10-2.04% (DS 0.01-0.25). There was a reduction in the viscosity-average degree of polymerization (DPv) of treated fabrics. However, the treatments did not significantly reduce mechanical properties (tensile strength, elongation at break and work of rupture) or thermal stability. The products were soluble in alkali solutions, but stable during storage at ambient conditions. Compared to the known carbamate processes reported in literature which can be applied only on wood pulp at the first state of fibre manufacture the advantages of this process are that not only this method can be employed on various cellulosic substrates at the latest state of the production but also the processing time can be reduced from hours to minutes. Moreover, the process is environmental friendly because it is a solventless procedure and employed less and non-toxic chemicals. (C) 2010 Elsevier Ltd. All rights reserved.