Thermal behavior of cross-linked carboxymethylchitosan membranes

Carboxymethylchitosan (CMCh) was submitted to reaction with genipin to result in cross-linked membranes (M-CMCh) exhibiting different average degrees of crosslinking ( ) according to the concentration of genipin used during the reaction. The effects of the viscosity average molecular weight (0.4 kDa < Mv < 1.9 kDa) of the parent CMCh, average degree of crosslinking (3 % <  < 18 %) and degree of crystallinity (14 % < CI < 18.9 %) of the resulting M-CMCh on its thermal stability were evaluated by carrying out TGA and XRD analysis, respectively. Results show that the cross-linked membranes (M-CMCh) are significantly less stable and exhibit lower crystallinity as compared to the parent CMCh. The viscosity average molecular weight of the parent CMCh has little effect on the thermal stability of M-CMCh while increasing the  slightly decreased the thermal stability as well as the crystallinity of the cross-linked membranes.