A sulfathiazole derivative with phosphaphenanthrene group (STZ) was successfully synthesized by covalently bonding DOPO and imine intermediate obtained from the condensation of sulfathiazole with p-hydroxybenzaldehyde. Its effect on the thermal, flame-retardant and mechanical properties of epoxy thermosets were comprehensively studied. The presence of STZ decreased the initial degradation temperature and glass transition temperature (T_g) of epoxy thermoset. STZ significantly improved the flame retardancy and fire safety of epoxy thermoset. With the addition of only 4 wt% STZ, the modified epoxy thermoset achieved an LOI value of 29.1% and V-0 rating in UL-94 test. Moreover, the peak heat release rate (PHRR) and total heat release (THR) in cone calorimeter test were decreased by 34.4% and 32.1% in comparison with those of pure epoxy thermoset. STZ showed high flame-retardant activity not only by releasing nonflammable gases and phosphorous radicals in the gas phase, but also by promoting the formation of dense and intumescent char layer with honeycomb-like hollow structure inside in the condensed phase. Because of the strong intermolecular action between STZ and epoxy macromolecular chain, the presence of STZ increased the tensile strength, while decreased the elongation at break of epoxy thermoset.

通过将DOPO和由硫代噻唑与对羟基苯甲醛缩合得到的亚胺中间体共价键合，成功合成了具有磷菲基（STZ）的硫代噻唑衍生物。全面研究了其对环氧热固性树脂的热学，阻燃性和机械性能的影响。STZ的存在降低了初始降解温度和玻璃化转变温度（T _g）环氧热固性材料。STZ大大提高了环氧热固性树脂的阻燃性和防火性。仅添加4 wt％的STZ，在UL-94测试中，改性的环氧树脂热固性材料的LOI值达到29.1％，V-0等级。此外，与纯环氧热固性材料相比，锥形量热仪的峰值放热率（PHRR）和总放热（THR）分别降低了34.4％和32.1％。STZ不仅通过在气相中释放出不可燃的气体和磷自由基，而且通过促进在凝结相内部形成具有蜂窝状中空结构的致密且膨胀的炭层，从而显示出高阻燃活性。由于STZ和环氧大分子链之间的强烈分子间作用，STZ的存在增加了抗张强度，