Abstract: Phenolic resin (PF) was widely used as matrix resin for ablative materials due to its excellent mechanical properties and ablation resistance. However, the char yield of traditional phenolic resin was too low to meet the higher requirement on ablative materials. Based on this background, a kind of zirconium acetate modified phenolic resin (ZPF) was prepared in this work, which had higher char yield than pure phenolic resin (PF). Then glass fiber reinforced zirconium acetate modified phenolic resin (GF/ZPF) composites were prepared. The effects of zirconium content on flexural strength and linear ablation rate of the composites were studied. And the changes of linear ablation rate and ablation morphologies of the composites with ablation time were observed and analyzed. The results showed that the char yield of ZPF was 68.7% at 1000℃, which increased by 21.7% than that of PF. The flexural strength of GF/ZPF composites reached up to 642MPa when the zirconium content of the resin was 14%. With the increase of the zirconium content from 10% to 15%, the linear ablation rate was reduced from 0.0305 mm/s to 0.0208mm/s. In addition, the linear ablation rate was rarely changed with increased ablation time, which indicated that the GF/ZPF composites had excellent ablation properties.

Key words: zirconium acetate modified phenolic resin, char yield, composites, bending strength, linear ablation rate