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

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。 Poplar wood fibers (PWF) of 850-2 000 μm 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 mechanical performance test after creep of PWF/HDPE composites were studied. And two-parameter exponential model, 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 deformation is 0.809 mm, and the flexural strength of the creep is 72.35% of the original value, and the elastic modulus increases by 10.67%. Among the three models, four-element Burgers model successfully simulates with the creep properties of PWF/HDPE composites. 国家自然科学基金(31460171);贵州省科学技术基金(黔科合J字[2015]2075号)