Topochemical modification of cotton fibres with carboxymethyl cellulose

Abstract

Adsorption of carboxymethyl cellulose (CMC) as a method to introduce charged (ionizable) groups onto cellulose cotton fibre surfaces was investigated. The method was based on application of a previously published method used for wood fibres. The amount of adsorbed ionizable groups was determined indirectly by analysis of CMC in solution by the phenol-sulphuric acid method and directly by conductometric titration of the fibres. Results from the two methods correlated well. The molecular weight and purity of the CMC had an influence on its adsorption onto cotton; high molecular weight CMC was preferentially adsorbed. The adsorbed charge correlated linearly with the amount of CMC adsorbed. The total charge of the cotton fibres could be increased by more than 50% by adsorption of CMC. It is expected that this modification procedure can be used in a wide spectrum of practical applications.

Cellulose Fibres Funcionalised by Chitosan: Characterization and Application

“…It was discovered that the total charge of cotton increased by more than 50 % in the case of all used CMC products. Even more, the modified fibres appeared to have better mechanical properties (Fras Zemljič et al 2006) (Table 3). Table 3.…”

“…Several methods available in literature describe how cellulose fibres are modified in order to obtain carboxyl groups: oxidation procedures, adsorption of anionic polymers and dyes, plasma activation, etc. (Browning 1967, Kaputskii et al 2006, Kotel'nikova et al 2003, Fras Zemljič et al 2006, Vesel et al 2010). In our previous research work, fibres were oxidized selectively as well as non-selectively with the aim of obtaining a different content of carboxyl groups (Fras Zemljič et al 2004).…”

“…Moreover, because of the capacity of cotton fibres to adsorb cationic surfactants, the rate of adsorption is increased by the previously adsorbed carboxymethyl cellulose (CMC) on the fibres' surfaces (Fras Zemljič et al 2006), see Fig. 8.…”

“…The adsorption of cationic surfactant onto fibres increases as the anionic charge on the fibres increases (due to CMC adsorption). Due to the attraction between surfactant cations and dissociated fibre carboxyl groups, a higher charge density on the fibres leads to a higher and faster adsorption of surfactant (Fras Zemljič et al 2006). This procedure of fibre anionization may be due to extremely anionic charge increase and improved mechanical fibre properties at the same time, very promising for irreversible chitosan binding.…”

Water redispersible cellulose nanofibrils adsorbed with carboxymethyl cellulose

“…The adsorbed CMC improved the mechanical properties of handsheets prepared from wood pulp and aided paper recycling (Duker et al 2008). CMC adsorbed onto cotton fibers was used to increase the charge density and adsorption capacity for surfactant (Fras-Zemljic et al 2006;Zemljic et al 2008). Therefore, CMC has been successfully used as an anchoring polymer for surface modification of cellulosic materials including CNFs.…”