本发明公开一种改性可膨胀石墨协同聚磷酸铵阻燃超高分子量聚乙烯材料的制备方法，包括以下步骤：A、将9，10‑二氢‑9‑氧杂‑10‑磷杂菲‑10‑氧化物溶于乙醇中得到混合液；B、向混合液中滴加甲醛回流，过滤干燥得到改性之后的DOPO‑CH2OH；C、将DOPO‑CH2OH和可膨胀石墨加入乙醇混合，搅拌，过滤得到改性的可膨胀石墨；D、将改性后的产物与聚磷酸铵按照一定比例和超高分子量聚乙烯混合模压得到阻燃的超高分子量聚乙烯复合材料；本发明将有机阻燃剂分子DOPO接枝到石墨表面，显著提升了材料的燃烧性能、拉伸性能和热稳定性等，并且具有无卤、低烟、无毒、无腐蚀性等优点。

The invention discloses a preparation method of a modified expansible graphite synergistic ammonium polyphosphate flame-retardant polyethylene material with ultra-high molecular weight. The preparation method of the modified expansible graphite synergistic ammonium polyphosphate flame-retardant polyethylene material with ultra-high molecular weight comprises the following steps: A, dissolving 9,10-dihydro-9-oxa-10- phosphaphenanthrene-10-oxide in ethanol to obtain a mixed solution; B, dropwise adding formaldehyde in the mixed solution for refluxing, and filtering and drying to obtain modifiedDOPO-CH2OH; C, adding DOPO-CH2OH and expansible graphite in ethanol and mixing, stirring, and filtering to obtain modified expansible graphite; and D, mixing the modified product with ammonium polyphosphate according to a certain ratio and ultra-high molecular weight and carrying out mould pressing to obtain the flame-retardant polyethylene composite material with the ultra-high molecular weight.The organic flame retardant molecules DOPO are grafted to the surface of graphite, the combustion property, the tensile property, the thermal stability and the like of the material are improved remarkably, and the modified expansible graphite synergistic ammonium polyphosphate flame-retardant polyethylene material with ultra-high molecular weight has the advantages of zero halogen, low smoke, zerotoxicity, zero corrosion and the like.