中文摘要：

研究了不同配比的聚磷酸铵（APP），季戊四醇（PER）组成的膨胀型阻燃剂及不同阻燃剂含量对低密度聚乙烯（LDPE）阻燃性能和力学性能的影响。m（APP）／m（PER）最佳为3：2，膨胀型阻燃剂质量分数最佳为30％。与纯LDPE相比，含有最佳配比和质量分数的阻燃剂体系的复合材料的极限氧指数从17．8％提高至24．5％,550℃的残重率从30．6％提高至87.0％；力学性能有所下降，拉伸强度从10．3MPa降为7．39MPa，断裂伸长率从115％下降到57％。阻燃LDPE的放热量比未阻燃的LDPE减少，说明形成的膨胀炭层对内部基材起着保护作用。550℃阻燃试样的残余物中成炭较致密，在炭层中除了含C外，还含有较大量的P和少量的N。

英文摘要：

The influences of intumescent flame retardants consisting of ammonium polyphosphate （APP） and pentaerythritol （PER） at different ratios and their different dosages on flame retardancy and mechanical properties of low density polyethylene （LDPE） were studied. The optimum mass fraction ratio of APP to PER was determined to be 3 ： 2; the optimum mass fraction of the intumescent flame retardant was 30%. Compared with pure LDPE, the limiting oxygen index of the composite system with the optimum ratio and the optimum mass fraction of the flame retardant increased to 24.5% from 17.8%, while the residue ratio at 550 ~C rose to 87.0% from 30.6%. In addition, the mechanical properties of the composite became inferior, involving the reduction in its tensile strength from 10.3 MPa to 7.39 MPa and the drop in its elongation at break from 115% to 57%. The exotherm of the flame retardant LDPE was obviously less than the pure LDPE reference; this fact indicated that the formed intumescent carbon layer had protected the interior matrix from further burning. In the residue of the flame retardant specimen tested at 550 ℃, the formed carbon was rather compact, which contained not only carbon, but also phosphor and nitrogen element in comparatively large quantity.