Synthesis and rheological behavior of a novel N‐sulfonate ampholyte chitosan

Abstract

Modified chitosan derivatives with different degrees of substitution varying from 0.17 to 0.96 were synthesized by the heterogeneous reaction of chitosan with 3-chloro-2-hydroxy propanesulfate in a neutral aqueous solution. The modified chitosans with a degree of substitution higher than 0.36 were soluble in water, whatsoever the pH. The structures of the polymers were characterized by Fourier transform infrared and 1 H-nuclear magnetic resonance spectroscopies. The potentiometric titration revealed that the modified chitosan had an isoelectric point at around pH ¼ 5.7, and its rheological behaviors in aqueous solution were studied under different conditions. The results showed that the modified chitosan had typical polyampholyte characteristics, which exhibited polyelectrolyte effect at pH ¼ 1.7 or 13 and antipolyelectrolyte effect at pH ¼ 8.

Recent biomedical advances with polyampholyte polymers

“…In addition, there has been increasing interest in the modification of bio‐based polymeric substrates to give them polyampholyte characteristics. Examples of this include the modification of chitosan through either its pendant OH or NH 2 groups, cellulose, dextran, and konjac glucomannan (a component of the tuber Amorphophallus konjac ) . Finally, there have been recent efforts in the synthesis of star and miktoarm copolymer structures with carefully controlled compositions of the star arms.…”

Synthesis and characterization of polyampholytic aryl-sulfonated chitosans and their in vitro anticoagulant activity

“…From figure 3, it is possible to observe that the reaction yield obtained by Amiji et al was slightly inferior to those we obtained as those theoretically obtained in the same conditions for CHT1S and CHT2S would be approximately 0.4 and 0.3, respectively. Besides Yin et al, according to a different reaction path, used variable ratios of 3-chloro-2-hydroxy propanesulfate in the range 1-5 compared to chitosan amino groups, measured DS in the range 0.17-0.89 (Yin, Li, Yin, Miao & Jiang, 2009). FTIR spectrum of chitosan in figure 4 displays a wide absorption band between 3000 and 3600 cm -1 related to O-H stretching from the hydroxyl and between 2800 and 3000 cm -1 related to the C-H asymmetric stretching.…”

“…In order to target O positions, the regioselectivity could be controlled by using protection-deprotection of the primary amino groups strategies (Nishimura et al, 1998;Yeh & Lin, 2008). Besides, chitosans carrying sulfonate groups on N position could be obtained by using reactants such as vinylsulfonate (Jung, Kim, Choi, Lee & Kim, 1999), propane sultone (Jung, Na & Kim, 2007) or 3-chloro-2-hydroxy propanesulfate (Jayakumar, Nwe, Tokura & Tamura, 2007;Yin, Li, Yin, Miao & Jiang, 2009). In particular, chitosan modification can be advantageously achieved by using the reductive amination reaction path proposed by Hall and Yalpani (Hall & Yalpani, 1980;Roberts, 1992), which consists in reacting alkyl or aryl aldehydic compounds on chitosan substrates yielding Schiff's bases intermediates directly reduced into secondary amines in the presence of sodium cyanoborohydride.…”

Zwitterionic Cellulose Carbamate with Regioselective Substitution Pattern: A Coating Material Possessing Antimicrobial Activity

“…In contrast to synthetic polybetaines, an increased solubility could be found for zwitterionic cellulose derivatives and, furthermore, biopolymers possess an inherent biocompatibility and biodegradability. Zwitterionic N ‐functionalized chitosan, or 6‐desoxy‐6‐aminocelluloses are comparable to synthetic polybetaines. Only a few cellulose‐based zwitterions are described where the isoelectric point and the properties in solution could be tuned by varying the substitution pattern –…”