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The failure mechanism of rigid polyurethane foam (RPUF) under room temperature (RT) and high temperature vibration conditions was investigated by experiment and finite element stimulation. Damaged RPUF specimens were prepared at different vibration amplitudes ranging from 0 to 19.879 mm at RT and 150 °C for different vibration times. The tensile test was utilized to evaluate the vibration damage degree of RPUFs, and the results exhibited that tensile strength decreased gradually with the increase of vibration amplitude and time at both RT and 150 °C. Thermogravimetric analysis and Fourier transform infrared spectroscopy illustrated that thermal degradation of RPUF is attributed to the decomposition of carbonyl urethane groups at 150 °C. The scanning electron microscopy analysis of the tensile fracture surfaces revealed that the vibration failure of RPUF mainly resulted from the existence of microcracks in cell structure. A finite element simulation was established by ABAQUS to study stress distribution of RPUF under different vibration loads, which then demonstrated that the microcracks are most likely to exist on the junction of two microcell units, which is due to convergence of stress in the process of vibration. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48343.

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The thermal stability and tribological properties of cyanate ester (CE) composites filled with Zirconium boride (ZrB 2 ) particles were investigated by experimental and numerical simulation. The results of thermogravimetric analysis and differential scanning calorimetry showed that the thermal stability of composites was improved by introduction of ZrB 2 particles. The tribological properties of composites including friction coefficient and wear rate measured by pinon-disk friction and wear tester were enhanced. Friction coefficient and wear rate of composites were decreased significantly with an increase of ZrB 2 particles content under dry and oil sliding conditions. The 5 wt% ZrB 2 particles reinforced CE resin composite presented optimal thermal stability and tribological performance due to good dispersion of ZrB 2 particles. The worn surfaces of composites were observed by scanning electron microscopy to explore wear mechanism, indicating that the dominant wear mechanism of composites was transformed from adhesive wear to abrasive wear after incorporation of ZrB 2 particles. Finite element model was established to study the distribution of friction stress. The results revealed that filling ZrB 2 particles in the friction process of composites could bear more friction stress than CE resin matrix, which further illustrated that abrasive wear is main wear mechanism of ZrB 2 /CE resin composites. POLYM. ENG. SCI., 59:602-607, 2019.