Effect of freeze-thaw cycle aging on properties of bamboo fiber/polypropylene composites

Bamboo fiber/polypropylene (BF/PP) composites are often used in the field of outdoor municipal engineering. In high latitude areas, the alternating effect of cold, heat, humidity, and freezing will seriously deteriorate the properties of the materials. In explore the aging resistance of BF/PP composites in high latitudes, BF/PP composites were prepared by synergistic modification of compatibilizer and coupling agent. After freeze-thaw cycle aging treatment, the physical and mechanical properties and apparent properties of the materials were studied. The creep behavior of the material was studied by 5400 s short-term creep test method, and the micro morphology and chemical compositions of the materials were analyzed by scanning electron microscopy and Fourier transform infrared spectroscopy. The results show that after 720 h freeze-thaw cycle aging, the retention rates of tensile strength, flexural strength, flexural elastic modulus, and notched impact strength of BF/PP composites are 76.90%, 86.89%, 82.81% and 71.83%, respectively. Deep cross cracks, holes, and faults formed in the BF/PP composite, and the surface hydrophobicity of the BF/PP composite decreased, and obvious color changes occurred. The 5400 s short-term creep behavior of BF/PP composites was further fitted by Burgers model, and the influence mechanism of freeze-thaw cycle aging on the creep resistance of BF/PP composites was explored.