2.3.2. X-ray diffraction (XRD)
XRD model D8-Advance Bruker AXS GmnH was used for tracking changes in the crystallinity of gelatin hydrogels after reinforcement with different amounts of CNCs. Hydrogels in the swollen state were freeze-dried using a freeze dryer model Christ Alpha 1–4 LD before they were ground into a powder. The powder was then placed uniformly on sample holders to make sure all the samples had the same X-ray exposure. Each sample was exposed to X-ray radiation using CuKα (λ = 0.1539 nm) generated at 40 kV and 30 mA, and 2θ angle of 5–80°.