Fabrication and performance characterization of the membrane from self-dispersed gelatin-coupled cellulose microgels

A new gelatin-coupled cellulose (GCC) microgel system was successfully prepared in NaOH/urea aqueous solution with epichlorohydrin (ECH) as a coupling agent via dialysis and self-dispersion pathway. The structure and property of the microgel and its membrane were characterized by elemental analysis, dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectra, gel permeation chromatography (GPC), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). It was concluded that successful coupling interactions occurred between cellulose and gelatin during the fabrication process, and the weight-average molecular weight of GCC microgel was up to 636.60 kDa with polydispersity index (PDI) of 1.015 approximately. The crystalline structure of the modified cellulose was destroyed, leading to GCC product self-dispersed in water in the absence of NaOH and urea. The GCC microgels had whisker-like structure, and their Z-average particle sizes were approximately 86.1 nm–150.2 nm and decreased with the increases of the gelatin content (W_Gel). In comparison with the water contact angle, swelling behavior and thermostability of the existing water-soluble cellulose derivative, the microgel membranes exhibited better water resistance and thermal resistance properties.