Preparation and characterization of the dialdehyde hydroxypropyl methylcellulose/collagen (DHPMC/COL) solutions

Dialdehyde hydroxypropyl methylcellulose (DHPMC)/Collagen (DHPMC/COL) solutions were prepared with different DHPMC contents (0–70 wt%). According to the viscosimetric method, all samples were compatible. The compatibility was related to Schiff’s base, which formed between the amino groups of collagen and the dialdehyde groups of DHPMC. When DHPMC content increased, the cross - linking degree increased, and the synchronous negative cross-peaks between the C-O(H) of DHPMC at 1031 cm −1 and amide bands of collagen at 1623 cm −1 , 1523 cm −1 , and 1238 cm −1 indicated that hydrogen bonds mainly formed between DHPMC and collagen. As a result, the thermal stability improved . The morphology showed more sheet-like structures than collagen. When the DHPMC content was 50 wt%, the thermal denaturation temperature (Td) and residual weight% were 8.5 °C and 10.22%, respectively, higher than other samples. However, the cross-linking degree decreased as the DHPMC content increased further. The intensity of negative cross-peak was decreased in synchronous correlation spectra, while the intensity of cross-peak at 1031 cm −1 was enhanced, indicating that hydrogen bonds formed between the C–O and C–O(H) of the DHPMC were enhanced. Consequently, the thermal stability decreased and more porous structures were observed compared to those when DHPMC content was 50 wt%. Graphic abstract