One‐pot synthesis in aqueous system for water‐soluble chitosan‐graft‐poly(ethylene glycol) methyl ether

Abstract

Chitosan is functionalized with poly(ethylene glycol) methyl ether (mPEG) at the amino and hydroxyl groups via a single step reaction in a homogeneous aqueous system. A chitosan aqueous solution obtained from the mixture of chitosan and hydroxybenzotriazole (HOBt) in water is a key factor in providing mild conditions to conjugate mPEG by using a carbodiimide conjugating agent. The reaction at ambient temperature for 24 h gives chitosan-g-mPEG with water solubility with mPEG content as high as 42%. This work demonstrates that a water-soluble chitosan-HOBt complex is an effective system for the preparation of chitosan derivatives via the aqueous system without the use of acids or organic solvents.

Surface‐pegylated chitin whiskers as an effective additive to enhance the mechanical properties of recycled ABS

“…The comparison of curve (a) (pure whiskers) with curve (c) (pegylated whiskers) shows the addition of a new peak at 1735 cm −1 (carbonyl groups) and an increase in the intensity of the peaks at 1650 cm −1 (amide groups), 1100 cm −1 (C–O–C) and 2871 cm −1 (C‐H bond), which suggests the grafting of mPEG . Yoksan et al .…”

Novel water soluble phosphonium chitosan derivatives: Synthesis, characterization and cytotoxicity studies

“…The possible mechanism of the interaction and complexation is shown in Fig. 1, which was also reported by Fangkangwanwong and Dai based on NMR study [27][28][29]. The complexes existing as salt form not only increased the water solubility of both chitosan and HOBt but also activated the amino groups of chitosan to react with the active ester of CTPC.…”

“…Finally, O-acylisourea reacted with A or B and the coupling reaction probably occur at C-2 to form an amide linkage. It was noted that the HOBt used in chitosan-HOBt system could also reduce the amount of generated N-acylisourea and moderate the reaction rate of the coupling reaction [29].…”

Polyethylene film surface functionalized with chitosan via γ-ray irradiation in aqueous system: An approach to induce copper(II) ion adsorptivity on PE

“…In general, HOBt is a conjugation additive for water soluble conjugation system. In the past, we found that HOBt forms an organic salt with chitosan as observed by 1 H NMR and enables chitosan to be a water soluble one [31,32]. There, the function of HOBt may not only activate the amino group of chitosan but also retarding the hydrogen bond of chitosan with the bulkiness of HOBt.…”