The modification of collagen with biosustainable POSS graft oxidized sodium alginate composite.

As a kind of renewable biological resource, leather collagen is the raw material of leather industry. The chrome tanning modified leather has high humidity and heat resistance, but there are some defects such as environmental pollution, harm to human health and shortage of chromium resources, so it is urgent to research chromium-free tanning to achieve clean modified leather colloidal. In the chromium-free tanning system, the modification of skin fibrin by bio-based material has the significance of environmental protection. Sodium alginate can be used as crosslinking agent to stabilize collagen. In this study, the polyhedral oligomeric silsesquioxane (POSS) grafted oxidized sodium alginate polymer composite (POSS-OSA-MAA) containing aldehyde group was prepared by two steps. Firstly, POSS grafted sodium alginate polymer composite (POSS-SAG-MAA) was prepared by graft polymerization with POSS, sodium alginate(SAG) and methacrylic acid(MAA) as raw materials. Then POSS-OSA-MAA was obtained by oxidation of POSS-SAG-MAA with sodium periodate. The aldehyde group highest concentration in POSS-OSA-MAA was 3.26 mmol ▪g-1, and the tanned leather shrinkage temperature was 73.1 °C. The X-ray photoelectron spectroscopy showed that POSS-OSA-MAA could form Schiff base structure with amino-containing substances and form multiple points crosslinking, and POSS-OSA-MAA could improve the moisture and heat resistance and thermal stability of skin.