On 2:1 melamine – Squaric acid dihydrate complex: The structure and vibrational spectra

Comparative Study of Gelatin Hydrogels Modified by Various Cross-Linking Agents

Gelatin is a natural biopolymer derived from collagen. Due to its many advantages, such as swelling capacity, biodegradability, biocompatibility, and commercial availability, gelatin is widely used in the field of pharmacy, medicine, and the food industry. Gelatin solutions easily form hydrogels during cooling, however, the materials are mechanically poor. To improve their properties, they are often chemically crosslinked. The cross-linking agents are divided into two groups: Zero-length and non-zero-length cross-linkers. In this study, gelatin was cross-linked by three different cross-linking agents: EDC-NHS, as a typically used cross-linker, and also squaric acid (SQ) and dialdehyde starch (DAS), as representatives of a second group of cross-linkers. For all prepared gelatin hydrogels, mechanical strength tests, thermal analysis, infrared spectroscopy, swelling ability, and SEM images were performed. The results indicate that the dialdehyde starch is a better cross-linking agent for gelatin than EDC-NHS. Meanwhile, the use of squaric acid does not give beneficial changes to the properties of the hydrogel.

Controlling the distance between hydrogen-bonded chloro-s-triazine tapes: crystal engineering using N-alkyl chains and the influence of temperature

Precise control of tape spacing in hydrogen-bonded alkyl-chain substituted chloro-s-triazines is demonstrated at 150–298 K, with some unexpected behaviour from the odd-number carbon derivatives.