Utilizing Thermal Energy for Crosslinking Gels: A Novel Rapid Approach

Abstract

A novel route was invented for utilizing thermal energy (at an elevated temperature of 110 ± 2 °C) to synthesize and crosslink gels from resorcinol and formaldehyde without using catalysts or buffers. The outcome gels are identified by various techniques such as Fourier transform infrared, Raman spectroscopy, thermal gravimetric analysis, X-ray diffraction, nano-scanning electron microscopy, energy-dispersive X-ray spectroscopy and surface area and porosity analyses. Resorcinol–formaldehyde gels prepared by this approach are also carbonized and activated to study their subsequent activated carbons. The gels and their corresponding activated carbons expose hierarchical pore structures with micro-, meso- and macroporous features. The average pore sizes of gels and activated carbons ranged from 3.5 to 62.9 nm and from 0.9 to 2.0 nm, respectively. The total surface areas of gels and activated carbons ranged from 0.01 to 176.15 and from 160.93 to 511.46 m2/g, respectively. Moreover, the total pore volumes of gels and activated carbons ranged from 0 to 0.546 and from 0.086 to 0.366 cm3/g, respectively. The results refer to how this novel approach could be used in the synthesis of resorcinol–formaldehyde gels in particular, and might be used in the synthesis of other gels in general. Due to the absence of added catalysts or buffers, this approach yields clean products that can be valuable in various sensitive applications such as biomaterials and pharmaceuticals, which require no impurities from extra reacting species.