Abstract
Sol-gel technology was utilized to derive the inorganic ingredients into the phenolic resin to fabricate phenolic resin/silica organic-inorganic hybrid ceramers. Tetraethyl orthosilicate (TEOS) was used as the monomer of the sol-gel system. This thesis is divided into three parts:The first part of this thesis is focused on the basic properties of the phenolic resin/silica hybrid materials. The internal phase interaction, thermal properties and the thermal degradation mechanism were discussed. Results show that in the phenolic resin/silica hybrid ceramer systems, the intermolecular hydrogen bonding between phenolic resin and silica is stronger than the intramolecular hydrogen bonding in the phenolic resin molecules.The fractions of hydrogen bonding of the hybrid ceramers are about 3 times higher than that of pure phenolic resin and of silica gel. From the DSC and TGA measurements, the Tg of the postcured ceramers is slightly higher than that of phenolic resin. At the same time, the thermal stability of the phenolic resin/silica hybrid ceramer is enhanced with the increasing of of inorganic ingredient content. Furthermore, the thermal degradation mechanism of the phenolic resin/silica ceramers was studied by FTIR and TGA/MS. Results were compared with those of phenolic resin.The second part of this thesis investigates the utilization of phenolic resin/silica ceramer on the matrix of fiber reinforced composites. Results show that the incorporation of inorganic ingredients could enhance the flexural modulus and does not affect the flexural strength of the composites. From DMA results, it is shown that the ceramer-based composites have better thermal resistance. Furthermore, the silica containing fiber reinforced composites were fabricated by adding pre-prepared silica particles and the properties were compared with those prepared by sol-gel method. It shows that the sol-gel technology could improve the distribution of the silica inside the composites and modify the physical properties and the fiber-matrix interface of the composites.The third part of this thesis is to study the properties of carbon/carbon (C/C) composites derived from the phenolic resin/silica ceramers. Results indicate that the existance of silica will alternate the crystalline parameters of the derived carbon matrix. Moreover, the ceramer based C/C composites contain higher density, lower open porosity, higher flexural modulus and better oxidation resistance under 750℃ than phenolic resin based C/C composites.