| In recent years, the content of the air PM2.5 fine particulate matter largely increased due to the fog and haze increased severely. And because the smaller particle size, rich large number of toxic and hazardous substances, long-term stays in the atmosphere and can be transported long distances, which have a great impact on air quality and human health. The condition must be improved. This article prepared PPS filter pore structure using a needling process, and then improves the performance of filter materials through the use of spunlace technology. Then improved the filter performance using PTFE emulsion, and explored the optimal process of PTFE emulsion after finishing by orthogonal experiment. Finally, test PPS acupuncture filter of pore structure using cone calorimeter, and then analysis its combustion performance.Results show that acupuncture filter materials with larger weight and needling density which have small mean pore size of micropores and large PM2.5 grade filtration efficiency as well as filter resistance. After analysis, the acupuncture filter has large aperture and low filtration efficiency which should be further improved. Acupuncture filter materials reinforced by spunlace process found that spunlace channel number from 1 to 6 times, the mean pore size is reduced, PM2.5 grade filtration efficiency increases. When spunlace pressure from 20bar increase to 60bar, the mean pore size is reduced, PM2.5 grade filtration efficiency increases. When the pressure increased up to 70bar, the efficiency of spunlace filtration decreases. The optimal spunlace process is obtained at tne condition of 5 times channel,60bar pressure spunlace process. The best PM2.5 grade filtration efficiency of filter materials is 26.76%. And the mean pore size of micropores is 29.13um. As to the filter materials by cupuncture, web entanglement effect, filtration efficiency and other aspects are better.Through single factor experiments of PPS filter by conducting PTFE emulsion finishing, found that finishing solution from 50g/l increased to 50g/l, the rate of PM2.5 grade filtration efficiency keeps stable after a beginning increasing, the mean pore size of micropores keeps stable after a beginning decreasing. When increasing the curing temperature from 140℃ to 220℃, the rise degree of the grade filtration efficiency of PM2.5 from large to small.there is a significant decline in the mean pore size, the mean pore size of micropores decreases largely.When added baking time from 1min to 9min the PM2.5 grade filtration efficiency of filter materials increased significantly, the mean pore size of micropores keep stable after declining. Through orthogonal experiment, the optimal process match of PM2.5 grade filtration efficiency were obtained:methods dipping coating, finishing concentration of 70g/L, the pre-bake temperature is 60℃, pre-drying time is 15min, baking temperature of 180℃, baking time is 5min. The PTFE membrane filter obtained by optimal process has small mean pore size of micropores, narrow pore size distribution and more uniform, with mean pore size of micropores of 13.78um, PM2.5 grade filtration efficiency of 46.36%, the filtration performance has been greatly improved.Finally, the combustion performance of PPS acupuncture filter was tested using a cone calorimeter. We found its pkHRR is only 75.26 kw·m-2, with a small thermal cracking speed and slow combustion, the release of CO is only 51.17 ug·g-1, with small combustion risk. |
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