Preparation and Characterization of Maleic Acid Grafted Chitosan

Abstract

Modification of chitosan (CHI) with maleic acid (MA) via maleic anhydride (MAn) was investigated in acetic acid solution, in the presence of cerium ammonium nitrate (CAN) as the initiator. The effects of reaction time, temperature, and CAN and MA concentrations on the grafting percentage were studied. The products were characterized by Fourier-transform infrared, differential scanning calorimetry, and 13 C NMR, in addition to gravimetric evidence to grafting. A maximum of 105% grafting was achieved under the reaction conditions of 0.12 M CHI, 2.0 M MA, and 0.091 M CAN by stirring for 3 h at 70 C. Dissolution and swelling properties of grafted products were tested in the pH range 3-11. Products up to 36.5% grafting were found to be soluble in aqueous solution, while those with higher grafting percentages (48-81%) were partly soluble in the pH range studied. The product with maximum grafting percentage (105%) swelled and acted as a polyampholyte gel.

Glycoproteins as a Platform for Making Proton-Conductive Free-Standing Biopolymers

“…For PGM-CHO and PGM-MA, this peak is sharper and has a higher intensity compared to the shoulder peaks of PGM and PGM-COOH, thus suggesting the existence of aldehydes mainly in the PGM-CHO and PGM-MA, whereas in PGM (before the first oxidation) and PGM-COOH (after the second oxidation of aldehydes to carboxylic acid), there is no substantial presence of aldehydes . After maleylation (PGM-MA), a new amide II peak appears at 1575 cm –1 corresponding to the C–N and N–H stretching in PGM-MA . The peaks at 1421 and 1344 cm –1 are correlated with the O–H bending and C–O stretching of maleic acids, respectively.…”

“…37 After maleylation (PGM-MA), a new amide II peak appears at 1575 cm −1 corresponding to the C−N and N−H stretching in PGM-MA. 55 The peaks at 1421 and 1344 cm −1 are correlated with the O−H bending and C−O stretching of maleic acids, respectively. As for the different free-standing PGM films (Figure S2), the appearance of amide I and II peaks suggests that the protein structure remains intact after crosslinking.…”

Preparation of In Situ Cross-Linked N-Maleoyl Chitosan-Oxidized Sodium Alginate Hydrogels for Drug Delivery Applications

“…As shown in Figure 2, the absorption peak at the wavelength of 3448.72 cm -1 presented in the spectra of MCS attribute to stretching vibration of -OH and -NH 2 which is overlapping , meanwhile weak absorption at 2931.80 cm -1 wavelength correspond to stretching vibration of C-H [23], [28] . Moreover, at 825.53 cm -1 is attributed to C = C groups in maleoyl [13], [29]. Hence, the characterisation by FTIR revealed that the synthesised compound is N-maleoyl chitosan (MCS).…”

Novel Maleic Acid, Crosslinked, Nanofibrous Chitosan/Poly (Vinylpyrrolidone) Membranes for Reverse Osmosis Desalination

“…A number of studies revealed that for pure PVP, the bands observed at 2924 cm −1 and 2892 cm −1 , 1664 cm −1 , 1461 cm −1 , and 962 cm −1 were attributed to CH 2 symmetric stretching, -C=O and C=C stretching, CH 2 bending, and out-of-plane ring C-H bending, respectively and another band obtained at 1286 cm −1 showed characteristic vibrations of C-N in PVP. The spectra for CA and CA-S1 to CA-S5 membranes showed strong peaks at 1659 cm −1 , which confirmed the presence of PVP in each blend [25,26]. A small new peak observed at 1714 cm −1 indicated the C=O vibrations of maleic acid, and the peaks shown at 827 cm −1 and 796 cm −1 are attributed to C-H rocking of the olefinic structure, confirming the incorporation of maleic acid on to the CS backbone [27].…”