Aimed at improving the efficiency of bio-based flame retardants, a starch-based, chemical-physical synergistic intumescent and halogen-free flame retardant system has been prepared in polypropylene (PP). Besides, the starch-based flame retardants have been modified via surface hydrophobicity to enhance the interfacial compatibility with PP. Surprisingly, limiting oxygen index (LOI) value of PP composites can reach as high as 33.5% with UL-94 V-0 rating when the total flame retardant content is 30 phr. Definitely, the synergistic effect of starch-based flame retardants and expandable graphite (EG) endows the better flame retardancy and anti-dripping ability of PP, which can be attributed to the conjunct chemical-physical intumescence action in improving the quality of charring layer. Finally, systematic analysis on char residue has revealed the synergistic flame retardant mechanism. This work has opened up a new path for exploiting the bio-based flame retardant with high performance in actual applications.

为提高生物基阻燃剂的效率，以聚丙烯（PP）为原料，制备了淀粉基、化学-物理协同膨胀型无卤阻燃体系。此外，淀粉基阻燃剂已通过表面疏水性进行改性，以增强与 PP 的界面相容性。令人惊讶的是，当总阻燃剂含量为 30 份时，PP 复合材料的极限氧指数 (LOI) 值可高达 33.5%，达到 UL-94 V-0 等级。毫无疑问，淀粉基阻燃剂和可膨胀石墨（EG）的协同作用赋予了PP更好的阻燃性和抗滴落能力，这可以归因于化学-物理膨胀共同作用对炭化层质量的改善。最后，对炭渣的系统分析揭示了协同阻燃机理。该工作为在实际应用中开发高性能生物基阻燃剂开辟了一条新途径。