Sodium carboxymethyl cellulose as a stabilizer for fabricating mineralized collagen films with improved wet mechanical properties

Collagen casings, as a type of collagen film, have weak mechanical properties when wet. Therefore, in this research, sodium carboxymethyl cellulose was used to make sodium carboxymethyl cellulose (CMC)-amorphous calcium phosphate (ACP) composite (CMC-ACP) to enhance the collagen film wet mechanical properties. Collagen films were immersed in different CMC-ACP suspensions containing different CMC ratios for 30 min. The wet mechanical properties of collagen films were tested after soaking in deionized water for 2 min. The optimal CMC concentration was determined to be 0.2%, with the Young's modulus (YM) of the collagen film increasing from 0.043 MPa to 0.054 MPa, elongation at break (EAB) increasing from 41.42% to 56.98%, tensile strength (TS) increasing from 1.51 MPa to 2.5 MPa, and toughness (TH) increasing from 316 kJ/m3 to 797.63 kJ/m3. The effects of CMC concentration on the effectiveness of CMC-ACP and the mechanism of action on collagen films were studied by using scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC). In conclusion, CMC-ACP can mineralize collagen films and improve their wet mechanical properties when using appropriate concentrations. [Display omitted] •Mineralization was used to improve wet state mechanical properties of collagen films.•ACP nanoparticles were formed and stabilized by CMC.•CMC-ACP entered the collagen film matrix and led to better water resistance.•CMC-ACP with a size