Quaternized and sulfated xylan derivative films

Xylan quaternized sulfate films were prepared from beech xylan (X) and compared with fully sulfated xylan films (XS). When quaternized xylan (QX) was prepared in the first step (DSQ = 0.55), than by sulfation of QX in the second step the fully substituted ampholytic derivative (QXS; DSQ = 0.33; DSs =1.67) could be obtained. By sulfation in first step, xylan sulphate (SX, DSs = 0.70) was obtained and by subsequent quaternization, SXQ film with DSQ = 0.55 and DSs = 0.33 which contained partially unsubstituted hydroxyls. The molar masses (M) of the film's soluble parts were increasing in order X < SX < SXQ < QX < XS < QXS. In all films there were some insoluble particles present as determined by the amount of recovered masses by SEC-MALS. The materials were further characterized by AFM, XRD,TG/DTG/DTA, NMR and mechanical testing. QXS and SXQ could form mechanically more stable films than XS specimens. (C) 2013 Elsevier Ltd. All rights reserved.