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

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.