Preparation and Properties of CMC Gel

Abstract

Novel elastic gel was obtained by immersing paste of sodium carboxymethylcellulose (CMC) in acid solution. The paste was prepared by mixing CMC and water at the concentration of 20%. Water absorption and mechanical strength of the resultant gel were evaluated after removing uncrosslinked CMC and acid. Combination of radiation crosslinking and the immersion in acid resulted precise molding and dimension stability of the gel. Maximum mechanical strength of the gel at 50% compression increased with acid concentration for the unirradiated and the irradiated samples at 5-20kGy. The gel prepared by irradiation at 5-lOkGy and the immersion did not cause rupture after 50% compression and was more than 100 times stronger than the radiation-crosslinked gel. The reason of the mechanical strength was attributed to crosslinks formed by the acid treatment The crosslinks by the irradiation had been referred to chemical bonds, whereas, those by acids were caused by hydrogen bonds, which was elucidated by FT-IR, ICP and TG-DTA measurements. Sodium in the carboxymethyl groups is replaced by hydrogen in the acid solution. The hydrogen bonds induced the decrease of CMC solubility in water and formed the elastic gel.

Hydrolytically stable foamed HKUST-1@CMC composites realize high-efficient separation of U(VI)

“…The relatively strong peaks at 3,420 cm −1 and 1,630 cm −1 can be attributed to the tensile vibration peaks of -OH and -COO − , respectively ( Tang et al., 2011 ; Xiao et al., 2018 ). The characteristic peak at 2,930 cm −1 is the asymmetric extension peak of -CH 2 in the hydroxymethyl (R-CH 2 OH) moiety on CMC ( Takigami et al., 2007 ), which indicates that the composite composed of HKUST-1 and CMC was successfully prepared. At the same time, the incorporation of CMC also has effects on the characteristic peaks of HKUST-1.…”

Bacterial Cellulose-Chitosan-Glycerol Biocomposite as Artificial Dura Mater Candidates for Head Trauma

“…Meanwhile, the absorption of aromatic ring occured at a wavelength of 1015-1650 cm -1 . Crosslinking of cellulose due to its hydrophobic-hydrophilic equilibrium, which gives rise to a collapse or an expansion of molecular chains by small temperature changes around its critical value [13]. Table 1.…”

Biomimetic Hybrid Systems for Tissue Engineering

“…Cellulose appears an ideal matrix for tissue engineering applications [ 15 ], alone or even blended [ 16 ] with other polymers like chitosan. Hydrogels can be prepared by crosslinking of aqueous cellulose esters [ 17 ], a procedure that avoids the limitations caused by insolubility of natural cellulose in aqueous media. Nanocellulose (i.e., cellulose nanocrystals [ 18 ], CNCs, cellulose nanofibers [ 19 ], NFCs, and bacterial cellulose [ 20 ], BC) can also be incorporated into polymer matrices to improve mechanical properties.…”