Effect of parameters of thermal treatment of resorcinol–formaldehyde resins on their chemical stability and 137Cs uptake efficiency

Synthesis of Hollow Silica Particles Using Acid Dissolvable Resorcinol‐Formaldehyde Resin Particles as Template

“…Therefore, the dissolution of the RF particles may be due to the hydrolysis of C−O‐C bands in strong acid solution, giving rise to the formation of large amount of water soluble oligomers. In addition, the hydrothermal treatment makes the RF particles more cross‐linked, thus forming a more stable molecular structure . It is also interesting to note that the silica shell on the hydrothermal treated RF particles is quite different from that shown in Fig.1, which is largely due to the changes of the surface groups on the RF particles.…”

“…The bands at 1103 and 1157 cm −1 are attributed to the C−O‐C stretching vibrations of methylene ether bridges between resorcinol molecules ,. After the hydrothermal treatment, the intensities of bands corresponding to the C−O‐C stretching vibrations reduce greatly while that assigns to the ‐CH 2 ‐ bending vibration increases remarkably, suggesting the transformation of the methylene ether bridges to the methylene bridges at high pressure and temperature . Therefore, the dissolution of the RF particles may be due to the hydrolysis of C−O‐C bands in strong acid solution, giving rise to the formation of large amount of water soluble oligomers.…”

“…Since the pioneering work on the synthesis of uniform resorcinol‐formaldehyde resin (RF) particles with controlled particles size via the extended Stöber method in 2011, the RF particles have been frequently used as the hard templates for producing hollow silica materials ,. However, the RF particles produced in alkaline condition are believed to be highly cross‐linked and do not dissolve in general solvent ,. They must be removed by calcination at elevated temperature, which usually leads to the reduction of the surface functional groups and may hamper their applications in many fields.…”

Porous Resorcinol-Formaldehyde Resins

“…Initial RF-resin denoted as RFR-i was obtained according to the method described in [26]. RFR-i (initial resorcinol formaldehyde resin) sample was prepared at a molar resorcinol-formaldehyde ratio of 1:1.…”

“…There have been attempts to obtain porous spherical RF-resins by adding olygomers containing CaCO 3 particles to hot condenser oil followed by solidification at 120 • C, yet the final product was chemically unstable in alkaline media due to low polymer cross-linking [26]. In addition, there are no works related to successful synthesis of porous RF-resins selective to Cs-137 using polymerization of dispersed phase followed by the dispersion phase removal.…”