不同牌号LDPE树脂的流变与结构性能

采用旋转流变仪、毛细管流变仪、凝胶渗透色谱（GPC）仪及稳态流变下的模型拟合试验，测试分析、比较了3种牌号低密度聚乙烯（LDPE）树脂的流变性能和结构性能。结果表明:LDPE-1，LDPE-2和LDPE-3 这3种LDPE树脂的动态流变曲线形状极其相似，其储能模量、损耗模量均随扫描角频率的增加而增大；其在不同剪切速率下的毛细管试验流变行为相似，但相对分子质量最小的LDPE-3树脂加工性能最好，而相对分子质量最大的LDPE-1对剪切敏感；这3种LDPE树脂的动态流变扫描、毛细管流变试验，以及在稳态流变下使用Cross拟合模型拟合试验结果所推断得出的其相对分子质量及其分布排序，与其结构性能的GPC测试结果均呈良好的相关性。

Rheological and structural properties of different grades of LDPE resins

The rheological and structural properties of3 grades of low density polyethylene（LDPE） resins were tested， analyzed and compared by means of rotary rheometer， capillary rheometer， gel permeation chromatography（GPC） and steady-state rheological model fitting test. The results showed that:the dynamic rheological curves of LDPE-1， LDPE-2 and LDPE-3 were very similar， and their storage modulus and loss modulus increased with the increase of scanning angular frequency. The capillary rheological behaviors of such 3 LDPE resins under the different shear rates were similar， but the processability of LDPE-3 resin with the smallest relative molecular mass was better， while LDPE-1 with the largest relative molecular mass was sensitive to shear. The dynamic rheological scanning and capillary rheological tests of such 3 LDPE resins， as well as the conclusion that the relative molecular mass ranking and the distribution width of such 3 LDPE resins were deduced by fitting the test results using the Cross model under the steady rheological state， which had good correlation with that of the GPC test results.