模压成型的杨木纤维/高密度聚乙烯复合材料蠕变性能和蠕变模型

采用长为850~2 000 μm的杨木纤维(PWF)增强高密度聚乙烯(HDPE), 利用模压成型法制备了PWF/HDPE复合材料, 对其进行了弯曲力学性能测试、无缺口简支梁冲击强度测试、24 h弯曲蠕变-24 h回复性能测试、1 000 h蠕变性能测试及蠕变后残余弯曲力学性能测试, 并利用两参数指数模型、Findley指数模型及四元件Burgers模型拟合蠕变曲线。结果表明: PWF/HDPE复合材料的弯曲强度为21.14 MPa, 弹性模量为2.31 GPa, 无缺口冲击强度为6.77 kJ/m2;24 h形变为0.803 mm, 24 h回复率为78.46%, 蠕变后弯曲强度下降了6.45%, 而弹性模量增加了8.95%;1 000 h形变为0.809 mm, 蠕变后弯曲强度保留了72.35%, 弹性模量增加了10.67%;3种模型中, 四元件Burgers模型拟合PWF/HDPE复合材料蠕变性能的效果较好。 

Creep properties and creep model of poplar wood fiber/high-density polyethylene composites prepared by compression molding

Poplar wood fibers (PWF)of 850-2 000μm reinforced high-density polyethylene (HDPE)composites were prepared by compression molding process.The flexural mechanical property test,un-notched beam impact strength test,24 h flexural creep-24 h recovery property test,1 000 h creep property test and residual flexural me-chanical performance test after creep of PWF/HDPE composites were studied.And two-parameter exponential mod-el,Findley’s exponential model and four-element Burgers model were used to fit creep curve.The results show that the flexural strength,elastic modulus and un-notched impact strength of PWF/HDPE composites are 21.14 MPa, 2.31 GPa and 6.77 kJ/m2 ,respectively.The 24 h deformation is 0.803 mm,and 24 h recovery rate is 78.46%. After creep,flexural strength decreases by 6.45%,but the elastic modulus increases by 8.95%.The 1 000 h de-formation is 0.809 mm,and the flexural strength of the creep is 72.35% of the original value,and the elastic modu-lus increases by 10.67%.Among the three models,four-element Burgers model successfully simulates with the creep properties of PWF/HDPE composites.