Creaming of Skim Natural Rubber Latex with Chitosan Derivatives

摘要

To recover residual rubber from skim nat-ural rubber (SNR) latex, a novel method was developedon the basis of the use of water-soluble chitosan deriva-tives. An anionic chitosan derivative, N,O-carboxymethylchitosan (CMCh), and a cationic chitosan derivative,N-(2-hydroxy)propyl-3-trimethylammonium chitosanchloride (HTACh), were prepared. It was found thatthe creaming process could be achieved with both chito-san derivatives. By the addition of 7.34-10.3-g/LCMCh, SNR latex was almost completely creamed, andno coagulation of SNR particles in the cream phaseoccurred. In the case of HTACh, the creaming processwas achieved with a lower concentration (<3.70 g/L)than in the case of CMCh, but the size of SNR particlesin the cream phase was larger. Solid-state ~(13)C-NMR,thermogravimetric analysis, and ζ potential measure-ment results provided evidence that the creaming ofSNR latex with CMCh and HTACh was controlled bythe depletion flocculation and adsorption mechanisms,respectively.