The incorporation of large loading of flame retardants generally causes embrittlement of materials. However, most of the rubbers and thermoplastic elastomers are flammable. Therefore, preparation of a flame retardant with potential toughening characteristics is urgently required for preparing materials with both good flame retardancy and toughness. The objective of the present work was to prepare a macromolecular flame retardant with good flexibility, that is, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-modified epoxidized polybutadiene (EPB–DOPO) via a creative approach of two-step reactions. First, polybutadiene (PB) was partially epoxidized to generate EPB; second, the reactive flame retardant DOPO reacted with epoxy groups to generate EPB–DOPO. EPB–DOPO with three epoxidation degrees was prepared: EPB5%–DOPO, EPB10%–DOPO, and EPB15%–DOPO. The chemical structure of EPB–DOPO was confirmed with proton nuclear magnetic resonance (¹H NMR) and Fourier transform infrared (FTIR) spectra. Thermogravimetric analysis (TGA) showed that EPB–DOPO had good thermal stability. EPB10%–DOPO and EPB15%–DOPO passed the UL-94 V-2 and V-0 rating, respectively, and the gas-phase flame retardation mechanism was deduced. The glass transition temperature (T_g) of EPB–DOPO prepared in this study was below −20 °C. Due to little char formation, EPB10%–DOPO and EPB15%–DOPO showed good resilience even after flame ignition. This study has provided a creative strategy to prepare a macromolecular flame retardant with good flexibility.

中文翻译：

---

制备具有灵活性的大分子阻燃剂的创造性方法：DOPO 改性环氧化聚丁二烯

掺入大量阻燃剂通常会导致材料脆化。然而，大多数橡胶和热塑性弹性体都是易燃的。因此，迫切需要制备具有潜在增韧特性的阻燃剂，以制备兼具良好阻燃性和韧性的材料。本工作的目的是制备具有良好柔韧性的高分子阻燃剂，即 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-改性环氧化聚丁二烯 (EPB-DOPO)两步反应的创造性方法。首先，聚丁二烯（PB）部分环氧化生成EPB；其次，反应性阻燃剂 DOPO 与环氧基反应生成 EPB-DOPO。制备了三种环氧化度的 EPB-DOPO：EPB5%-DOPO、EPB10%-DOPO、和 EPB15%–DOPO。EPB-DOPO的化学结构经质子核磁共振证实（¹ H NMR）和傅里叶变换红外（FTIR）光谱。热重分析 (TGA) 表明 EPB-DOPO 具有良好的热稳定性。EPB10%–DOPO 和 EPB15%–DOPO 分别通过了 UL-94 V-2 和 V-0 等级，并推导了气相阻燃机制。玻璃化转变温度（Ť_克EPB-DOPO的）在本研究中制备低于-20℃。由于几乎没有炭形成，EPB10%–DOPO 和 EPB15%–DOPO 即使在火焰点燃后也表现出良好的回弹性。该研究为制备具有良好柔韧性的高分子阻燃剂提供了一种创造性的策略。