| In the system of fire environment, clothing and body, fire environment is a prerequisite,clothing is the way to study, and demand for human body is the basis and purpose for study. Theeffect of environment on clothing and human can not be ignored. All kinds of external factorsincluding high heat flux, thermal radiation, sunlight, moisture and stress are the main factorscontributing to the decline on functions of firefighter protective clothing. In this paper, fabricscommonly used for firefighter protective clothing were selected. There were four kinds of outershells including navy blue NomexIIIA, soiled yellow PBI fabric, orange red domestic aramidfabric and dark orange NomexIIIA. PTEF composite film was used as moisture barrier. Feltedinsulation was used as insulating layer. Flame-retardant viscose was used as comfortable layer.Light and moisture aging experiment was designed with light intensity at5.4±0.27kW/m2between0to60minutes and three kinds of wetting degrees that is not wetting, about40%ofmoisture content and saturated wetting.Then, surface color difference, physical and mechanicalproperties and thermal protective performance of fabrics were evaluated in laboratory tests. Theresults showed that the longer time of exposure to light or the bigger wetting degree, the darkerfabric color, and the greater color difference value (P<0.001). Fabric color of PBI fabric wasmaximum with17.68of vaule after60minutes. With increasing photoaging time or wettingdegree, tear strength and breaking strength of fabrics decreased (P<0.05). After60-minutesphotoaging, PBI fabric had the best retention of dry and wet strength with about83%of reductionratio of tear strength in saturated wetting condition, while domestic aramid fabric’s was about76%,whose weft breaking strength was below standard and retention of strength was worst. The lightand moisture aging treatments was beneficial to improve thermal protective performance (P<0.05).The relationship model between fabric color and retention rate of mechanical strength wasestablished. The results revealed that all of models showed high fitting degree with range of meanvaule of prediction error from1.5%to9.6%. Light and heat aging experiment was designed with light intensity at5.4±0.27kW/m2between0to60minutes and heat radiation intensity at5.4±0.27kW/m2between0to30minutes.Then, surface color difference, physical and mechanical properties and thermal protectiveperformance of fabrics were evaluated in laboratory tests. The results showed that the effect of onvalue of fabrics was significant (P<0.001). After60-minutes light and heat aging, value of fabricsincreased significantly, and PBI’s color difference was maximum with21.47of value, while whatthe navy blue NomexIIIA was minimum with14.72of value. With increasing light and heat agingtime, tear strength and breaking strength of fabrics decreased (P<0.001). The decline on reductionratio of tear strength of domestic aramid fabric was most obvious with46.78%. After60-minuteslight and heat aging, weft breaking strength was below standard100N, so that all of fabrics couldnot continue to use. With increasing light and heat aging time, the TPP vaule of outer layer andmultilayer increased. With the same time, according to the aging degree of aromatic polyamidefiber fabrics exposed to different aging forms, heat aging showed the maximum damage tofunctions of fabrics, followed by light and heat aging, and the minimum was light aging, so therule was as follows, heat aging> light and heat aging> light aging. However, what PBI fabricfollowed was light aging> light and heat aging> heat aging in30minutes, and what PBI fabricfollowed was the same as aromatic polyamide fiber fabrics’ after over30minutes. Therelationship model between fabric color and retention rate of mechanical strength was established.The results revealed that all of models showed high fitting degree with range of mean vaule ofprediction error from2.4%to7.3%.Finally, the relationship model between fabric color and retention rate of mechanical strengthwas established under the interaction of light, moisture and heat. The results revealed that all ofmodels showed high fitting degree with range of mean vaule of prediction error from2.0%to7.2%. |
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