Research On Aerogel-based High Performance Thermal Protection Textile New Materials

Protective clothing and textile-based equipment are critical for firefighters to ensure their safety and health.According to the statistics,sudden cardiac deaths and heat stress account for the largest shares of the firefighter deaths(59%).This indicates that the traditional thermal protective clothing has great disadvantages and the critical issue associated with it is the heat stress.The weight and thickness of the current clothing system significantly reduce the comfort performance of protective clothing.Due to its three-dimensional net structure,SiO2 aerogel has excellent thermal insulation.In this study,SiO2 aerogel and phase change materials(PCM)were effectively incorporated with textile materials and a light and high-performance heat insulation film with improved protective and comfort performance was developed.A modified thermal protective performance(TPP)tester was applied to evaluate the thermal protective performance.Two approaches(TPP/RPP and minimum exposure time(MET)approach)were applied,and the thermal protective performance and stored energy performance were discussed under three simulated heat intensities(low,medium,and high intensity).The cone calorimeter test was used to explore the thermal degradation from the fabric systems.Additionally the moisture and its distribution effect on performance provided by fabric system were explored,and the mechanism associated with heat and mass transfer was analyzed.The effect of thermal insulation film on thermal protection was analyzed and simulated using numerical model.The temperature,heat flux distribution and their changes in mutilayer fabric systems were revealed,especially the synergistic effect of microencapsulated phase change materials(MPCM)and aerogel.Also the influence of test parameters on thermal protective performance was predicted.In the developing process of light and high-performance heat insulation film,the influence of process and parameters on thermal conductivity and protective performance were investigated.The optimum parameters were determined.That is,compared with the mass of waterborne polyurethane resin,the content of hydrophilic aerogel and MPCM were selected to be 12.5%,and the phase-change temperature was 40 ℃.Ratio of absolute ethanol to distilled water was selected to be 5:3.The thickness and velocity of scraper were set to be 500 μm and 50 mm/s,respectively.An improved performance of the film was achieved,such as thermal conductivity,protective performance,mechanical property,surface property and water vapor permeability.Two approaches(TPP/RPP approach and MET approach)were applied to evaluate the thermal protection performance.The result demonstrated that the thermal protective performance of the new fabric systems were much better than that of the traditional fabric systems.However,their thermal degradation property showed low performance.The parameter associated with thermal degradeation included heat release rate(HRR),smoke production rate(SPR)and mass loss.Also,when the system got wet,the results showed that the performance changed significantly.Based on these results,a prediction model was developed,and validated by experimental data.The effect of this film on the fabric system’s heat conduction process was analyzed and the impact of different parameters on thermal protective performance was investigated.This study provides some fundamentals for new material engineering and development.