Creaming of Skim Natural Rubber Latex with Chitosan Derivatives

To recover residual rubber from skim natural rubber (SNR) latex, a novel method was developed on the basis of the use of water-soluble chitosan derivatives. An anionic chitosan derivative, NO-carboxymethyl chitosan (CMCh), and a cationic chitosan derivative, N-(2-hydroxy)propyl-3-trimethylammonium chitosan chloride (HTACh), were prepared. It was found that the creaming process could be achieved with both chitosan derivatives. By the addition of 7.34-10.3-g/L CMCh, SNR latex was almost completely creamed, and no coagulation of SNR particles in the cream phase occurred. In the case of HTACh, the creaming process was achieved with a lower concentration (<3.70 g/L) than in the case of CMCh, but the size of SNR particles in the cream phase was larger. Solid-state C-13-NMR, thermogravimetric analysis, and (potential measurement results provided evidence that the creaming of SNR latex with CMCh and HTACh was controlled by the depletion flocculation and adsorption mechanisms, respectively. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 1022-1031, 2010