聚乙烯粉料粒径分布对熔体质量流动速率的影响

选择不同生产工艺的4种聚乙烯粉料，使用振筛机和不同孔径筛网进行筛分，得到不同粒径范围的聚乙烯粉料，用熔融指数仪测试这些粉料的熔体质量流动速率（MFR），考查不同粒径范围的聚乙烯粉料MFR的差异以及聚乙烯粉料粒径分布与MFR的关系，分析了聚乙烯粉料MFR测试结果的重复性与粉料粒度分布的关系，提出了在测试过程中如何正确操作减小MFR测试误差的方法，为粉料MFR的测定提供指导。结果表明，聚乙烯粉料的粒径分布对MFR有较大影响，通过测试前处理和规范称量时取样，可显著提高MFR测定结果的重复性。

Effect of particle size distribution of polyethylene powders on melt mass?flow rate

Four types of polyethylene powders prepared by using different production processes were selected to prepare the polyethylene powders with different particle size ranges using vibrating screen machine equipped with different pore size screens. The melt mass?flow rate （MFR） of these powders was measured by melt index instrument， and the difference of the MFR of polyethylene powders in different particle size ranges and the relationship between the MFR and particle size distribution of polyethylene powders were investigated. The relationship between the repeatability of MFR test results and particle size distribution of the powders was analyzed. A method for reducing the test errors of MFR in the test process was proposed， which provided guidance for the measurement of the MFR of the powders. The results indicated that the particle size distribution of polyethylene powders had a great influence on MFR. The repeatability of MFR can be improved by pretreatment and regular sampling.