The thermal stability of the T700 carbon fiber epoxy composites, which had been tested under different conditions (nonvibration plus nonscrubbing airflow, vibration, scrubbing airflow, and vibration plus scrubbing airflow), were investigated according to the obtained weight loss behavior, integral program decomposition temperature (IPDF), and activation energies (E) by using thermogravietry-differential thermal analyzer. The results indicate that the weight loss ratio, IPDF, and E of T700 carbon fiber epoxy and its residues in the third and fourth layers are similar under the nonvibration plus nonscrubbing airflow and vibration, and the thermal stability under the vibration condition is slightly stronger. In addition, the weight loss ratio, IPDF, and E of the epoxy and its residues in materials are also similar under scrubbing airflow and vibration plus scrubbing airflow, and the thermal stability under vibration plus scrubbing airflow is better. However, it is significantly less than the thermal stability of materials under nonvibration plus nonscrubbing airflow and vibration. Therefore, it can be found that the vibration exacerbates the flame severity and the scrubbing airflow has a significant cooling effect on the material during the airworthiness fire protection test, which have guiding significance on the airworthiness fire prevention items formulation of carbon fiber composite.
K E Y W O R D Sactivation energies, carbon fiber epoxy, integral program decomposition temperature, weight loss ratio
The hydrotalcite has been chemically modified by using the ion exchange method to insert dihydrogen phosphate between the carbonate-type magnesium-aluminum hydrotalcite layers. And then, the effect of modified hydrotalcite on the flame retardancy and smoke suppression properties of flexible polyurethane foam (FPUF) has been investigated using limiting oxygen index (LOI) method, cone calorimeter test (CONE), smoke density chamber, flue gas analyzer, and scanning electron microscope (SEM). The current indicated that the LOI of flame-retardant modified FPUF was increased to 25.4%. And the peak heat release rate (PHRR) and total heat release (THR) of the samples were decreased by 74.9 kW/m 2 and by 9.7 MJ/m 2 , respectively. Additionally, the total amount of flue gas produced by combustion was reduced by 157.7 m 2 /m 2 , and the maximum concentration of carbon monoxide (CO) gas decreased from 51.3 to 23.8 mg/m 3 . Based on these data, it can be found that the hydrotalcite modified by dihydrogen phosphate intercalation had an excellent flame-retardant and smoke-suppressant effect, and 15% of modified hydrotalcite was the most appropriate amount during the combustion process of the modified FPUFs.
Flame‐retarded rigid polyurethane foam (RPUF) conferred by an amino trimethylphosphonate iron (Fe2+‐ATMP) and expandable graphite (EG) compound flame retardant has been successfully fabricated by one‐step all‐water foaming method. The combustion characteristics of the RPUFs and the synergistic effect of Fe2+‐ATMP and EG on RPUF have been studied based on limiting oxygen index (LOI), smoke toxicity analysis, cone calorimeter (CONE), thermogravimetric (TG) analysis and thermal decomposition kinetics analysis. The current results indicated that the flame retardancy and thermal stability of the RPUFs modified by Fe2+‐ATMP and EG had been improved obviously and the contents of smoke toxic gases had been significantly reduced. When the ratio of Fe2+‐ATMP to EG was 1:5, LOI of the modified RPUF was the highest (27.1%). And its peak heat release rate (PHRR) and total heat release (THR) were the lowest, which were 135 kW/m2 and 15.7 MJ/m2, respectively, and were 40.5% and 17.8% lower than RPUF‐0. It also showed that the modified RPUF with a Fe2+‐ATMP to EG ratio of 1:5 had the best flame retardancy, smoke suppression, and thermal stability. The present work can provide some reference and guidance for flame retardant modification of polyurethane foam.
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