中文摘要：

通过氧指数测试、热重分析和力学性能测试研究了超细硼酸锌对由聚磷酸铵与季戊四醇组成的膨胀型阻燃剂（IFR）阻燃的低密度聚乙烯阻燃性能和力学性能的影响。结果表明：超细硼酸锌与膨胀型阻燃剂以4．2：25．8质量比组成的复合阻燃剂的协同阻燃效果最好，含量达到30％（以PE-LD计）时，氧指数从24．5％（IFR阻燃的PE-LD）提高至26．2％，力学性能亦有一定程度的改善，拉伸强度从7．39SPa升高到8．51SPa，断裂伸长率从57％提高到68．1％。热重分析表明当温度高于540℃后，复合阻燃剂阻燃的PE-LD明显比IFR阻燃的PE-LD失重变慢，高温残重率增加。从扫描电镜和能谱分析可知，阻燃试样550℃的灼烧样品成炭较致密，在炭层中除了含碳外，还含有较大量的磷元素和少量的氮元素，可能与其凝聚相阻燃机理相关。

英文摘要：

The influences of the ultrafine zinc borate on the flame retardancy and mechanical properties of low density polyethylene （PE-LD） containing intumescent flame retardant（IFR） composed of ammonium polyphosphate （APP） and pentaerythritol （PER） were investigated by LOI test, TG analysis, and mechanical test. When the mass ratio of ultrafine zinc borate to IFR was 4.2 ： 25.8 and the total flame retardant mass content was 30 % phr, the LOI was 26.2 % compared to 24.5 % of PE-LD containing IFR alone. The tensile strength and elongation at break was 8.51 MPa and 68.1% compared to 7.39 MPa and 57 %, respectively. TG analysis showed that the mass loss rate of PE-LD with ultrafine zinc borate was smaller than without, and the residue was higher when the temperature above 540℃. The SEM and EDS indicated that the compact residue contained some amount of phosphorus and nitrogen, which implied a condensation mechanism for the flame retarding.