Study on the Characterization of Physical, Mechanical, and Creep Properties of Masson Pine and Chinese Fir Wood Flour-Reinforced High-Density Polyethylene Composites.

Improving the physical, mechanical, and creep properties of wood fiber-reinforced polymer composites is crucial for broadening their application prospect. In this research, seven types of high-density polyethylene (HDPE) composites reinforced with different mass ratios of Masson pine ( Lamb.) and Chinese fir [ (Lamb.) Hook.] were prepared by a two-step extrusion molding method. The mass ratios of the two fibers were 60:0, 50:10, 40:20, 30:30, 20:40, 10:50, and 0:60, respectively. The surface color, density, dimension stability, bending, tensile, impact properties, dynamic mechanical properties, and 24 h creep properties at a 10% stress level of the seven composites were investigated. Additionally, the Rule of Mixtures (ROM), the Inverse Rule of Mixtures (IROM), the Hirsch models, and the improved model were employed to simulate the mechanical properties, while the Findley index model, the two-parameter index model, and the modified ExpAssoc model were employed to simulate the creep performance of the composites. This study revealed that as the proportion of Chinese fir wood flour increased, the mechanical properties of the composites gradually improved, the storage modulus showed an increasing trend, while the loss modulus decreased, and the overall creep strain of the composites increased. Among the various models, the modified model simulated the mechanical properties of the composites the best, while the modified ExpAssoc model simulated the creep behavior most effectively.