Preparation, characterization, structure, and dynamics of carboxymethyl chitosan grafted with acrylic acid sodium salt

Abstract

Graft copolymerization of different vinyl monomers onto chitosan (Cs) and its derivatives can alter their properties and consequently expands their potential applications. In this study, carboxymethyl chitosan (CMCs) was prepared and characterized. Graft copolymerization of acrylic acid sodium salt (AAs) onto CMCs was accomplished by using ammonium persulphate (APS)-induced free radical polymerization in aqueous medium under nitrogen atmosphere. Occurrence of grafting was confirmed and the effects of [AAs], [APS], reaction time, and temperature on the extent of grafting were studied. The influence of grafting yield on the structure and dynamics was also investigated by using differential scanning calorimetry (DSC), two-dimensional wide-angle X-ray scattering (2D-WAXS), scanning electron microscopy (SEM), and dielectric spectroscopy. Preliminary study, using dielectric spectroscopy, was carried out to the CMCs-g-AAs copolymer with grafting percent $ 2900%, as an example, in a wide range of temperature (from 299 to 473 K) and frequency (from 1 Â 10 À2 to 1 Â 10 5 Hz). One relaxation process with Arrhenius type was detected. This process has the characteristics of a secondary relaxation process related to local chain dynamics with activation energy of 53 6 3 kJ/mol.

Structure and dynamics of polypyrrole/chitosan nanocomposites

“…The temperature dependence of σ DC shown in Fig. (a) follows Arrhenius temperature dependence as follows: …”

New trimethyl chitosan-based composite nanoparticles as promising antibacterial agents

“…In the case of TMCS, the spectra demonstrated a peak at about 3320-3400 cm À1 which can be attributed to the N-H extension vibration, O-H stretching vibration, and the intermolecular Hbonds of the polysaccharide moieties. The band appeared around 2870 cm À1 is assigned for the stretching vibrations of the aliphatic C-H bonds whereas, the weak signal noted at 1656 cm -1 is due to the amide C¼O stretching 4 . The spectra of the resulting nanocomposite showed the bands of both copolymer and TMCS with few alterations.…”

“…Among the natural polymers, polysaccharides such as chitosan (CS) and CS derivatives have been widely used due to their biodegradability, biocompatibility, low toxicity, and superior antibacterial activities [1][2][3] . A great deal of interest has also recently focused on the use of polymers and copolymers in developing nanocomposites due to their desirable properties and enormous valuable applications in bio-related fields 4 .…”

The Oral Delivery of Proteins Using Interpolymer Polyelectrolyte Complexes

“…Further alginate-chitosan PECs were developed by El-Sherbiny and colleagues involving a carboxymethylchitosan(CMC)-sodium acrylate copolymer, which could be complexed with calcium-crosslinked alginate and a PEGylated form of chitosan [99][100][101][102]. By grafting sodium acrylate to the CMC, the number of carboxylic groups within the PEC structure were increased.…”

“…Coating of PECs with PEGylated chitosan and removal of majority of primary amines from chitosan structure offers control of protein release over pH range of GI fluid [99][100][101][102] Chitosan, calcium-crosslinked alginate, dextran sulfate, PEG/poloxamer and albumin Protection of insulin against pepsin degradation in vitro Insulin bioavailability in diabetic rats of 13% Insulin appears to be absorbed transcellularly [24][25][26]108] Thiolated poly(aspartic acid) and chitosan…”