Resorcinol formaldehyde hydrogel: Synthesis, polymerization, and application in ceramic gel-casting

In the present study, resorcinol formaldehyde (RF) hydrogel was successfully synthesized and applied in the gel-casting process. The polymerization of the gel system and the effects of catalysts on the mechanical properties of the ceramic preform were investigated. Changing the type of catalyst to control the gel reaction rate enabled the in situ “immobilization” of the B4C particles, thereby enabling the preparation of B4C/C porous preforms with a uniform structure and controllable pore size. The results revealed that using Na2CO3, having a high polarizing power Na+ and a high degree of hydrolysis CO32–, as a catalyst, the B4C/C porous preforms with low porosity and best mechanical properties can be obtained. Further, the flexural strength and compressive strength could reach 21.2 MPa and 52.2 MPa, respectively. [Display omitted]