Preparation and properties of phosphorus‐ and silicon‐modified phenolic resin with high ablation resistance

ABSTRACT In order to further improve the ablation resistance of common phenolic resins, a modified phenolic resin containing phosphorus and silicon (SPPR) was synthesized and the corresponding properties were evaluated. With phosphorus and silicon involved in the macromolecule, SPPR showed excellent flame retardancy and obviously enhanced value (44.8%) of the limiting oxygen index. The thermal stability and charring performance of SPPR were greatly improved, with maximum decomposition temperature of over 500 °C and carbon yield of 60.1% in nitrogen. Differential scanning calorimetry indicated that the curing temperature shifted from 157 °C for the conventional phenolic resin to 182 °C for SPPR. Moreover, an improvement of impact strength from 4.3 to 16.5 kJ m −2 confirmed that incorporation of flexible SiO chain had a noticeable effect on the mechanical properties of SPPR. Such a modified phenolic resin has promising application prospects serving as an ablation material with high performance. © 2019 Society of Chemical Industry