Preparation and properties of a biodegradability superabsorbent composite based on flax cake protein‐g‐poly (acrylic acid)/Kaolinite

Abstract The protein‐based superabsorbent composite FCP‐g‐PAA/Kaolinite is prepared by grafting acrylic acid (AA) into the flax cake protein (FCP) using free radical polymerization in this study. The chemical structure, thermal stability, and the morphology of the FCP‐g‐PAA/Kaolinite are characterized by Fourier transform infrared, Thermogravimetric analysis, and scanning electron microscope. The results show that AA was grafted successfully into FCP. And, it has the maximum swelling capacity where the MBA concentration, APS concentration, Kaolinite concentration, FCP concentration, neutralization degree, and reaction time was 0.13%, 1.4%, 8%, 9%, 70% and 2 h, respectively. The swelling capacity reaches 860 g/g in distilled water, 238 g/g in tap water and 78 g/g in 0.9% NaCl. In addition, its water absorbency can still reach 60% after reuse for six times and the water retention rate of the material was 70% after 12 h. Therefore, FCP has a broad application prospect as a material for preparing superabsorbent composite.