| Flame retardant performance and thermal protection performance are the main indicators for evaluating the safety performance of fire protection clothing.Safety performance accounts for about 55%of the protective performance of fire protection clothing,which is mainly related to the flame retardant outer layer,and the flame retardant outer layer is related to the complex and changing fire environment.direct contact,Therefore,it is of great significance to study the flame retardant protective performance of fire retardant outer fabrics of fire protection clothing.This article first studied the flame retardant properties of fire retardant outer fabrics.The vertical combustion method,the limiting oxygen index method and the microcalorimeter method were used to test the damage length,LOI and related indexes of the seven kinds of fabrics.The results show that during vertical combustion,material is the main factor affecting the damage length of the fabric,followed by the fabric's physical properties such as breathability,thickness,and areal density;During the limiting oxygen index test,thickness and area density have a greater impact on the limiting oxygen index of the fabric,and blending will increase the limiting oxygen index of the fabric;In the process of micro calorimetry,the material is the key factor affecting the heat release,and the material is also the key factor affecting the cracking temperature.The reasons for the flame retardancy of viscose fibers were analyzed by TG,EDS,and SEM.The results showed that the limit oxygen index of viscose fibers was increased and the heat release capacity was weakened due to the addition of Si,Na,Al,and Ca.The relationship between the three flame retardant test methods was analyzed,and the results showed that the correlation among the three flame retardant test methods was not obvious.Secondly,this article compares and analyzes five thermal protection test methods of flame retardant fabrics.Correlation analysis of three test methods under the condition of radiant heat source was performed using RPP,adjusted RPP and HRTP methods.The experimental results show that the correlation between RPP method and HRTP method is stronger than that between RPP method and adjusted RPP method under the action of pure radiant heat source.The correlation between the two test methods under flame conditions was explored by the TPP method and the FPT method.The experimental results show that,under the same heat flux density,convection heat is stronger than radiant heat on the thermal degradation of fabrics.Correlation analysis was performed on five test methods.The experimental results show that the self-made anti-radiation thermal penetration meter has a good correlation with the other four test methods,so the HRTP method is the best in the case of simply evaluating the protective performance of the fabric.Then,the radiant heat protection performance of the fabric is studied in this paper.First,the HRTP and RPP methods obtained in the previous chapter are used to analyze the radiant heat protection performance of the fabric under low radiation and high radiant heat flux densities,respectively.The experimental results show that when the heat flux density is 1kw/m~2,the thermal protection coefficient of the fabric is about80%.As the thermal flux density increases,the thermal protection factor of the fabric decreases by about25%and the thermal protection factor is about 55%.When the heat flux density is increased to 4kw/m~2,the thermal protection coefficient of the fabric is about 45%.The results of RPP experiments show that under different heat flux densities,the RPP value of essential flame retardant fabrics decreases with increasing heat flux density,and the RPP value of non-essential flame retardant fabrics decreases non-monotonically with increasing heat flux density.The relationship of heat flow density is non-linear.In addition,the actual value of the index k of the relationship between the secondary burn time and the heat flux density is less than the theoretical value,which indicates that as the heat flux density increases,the burn time decreases more than the heat flux density,and the RPP value decreases.In addition,the relationship between the macroscopic and microscopic appearance changes of fabrics and thermal protection performance was studied,and the results showed that there was no corresponding relationship between the macroscopic and microscopic appearance changes of fabrics and radiation thermal protection performance;the secondary burn time deepened with carbonization and microstructure changes The corresponding secondary burn time gradually decreases.Finally,this article explores the relationship between flame retardancy and thermal protection of fabrics.The test results show that there is no obvious correspondence between flame retardant performance and thermal protection performance. |
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