| With the increasingly severe environmental pollution,the development of renewable energy is of great significance.At present,there are two main ways to apply PCM to textiles,namely spinning method and post-finishing method.In the spinning process,phase change microcapsules are added into the spinning solution to spin,which has good washable performance,but its process is more complicated.The post-finishing method is to finish the phase change materials on the textiles by dipping or coating,which has the advantages of simple operation,poor water resistance and easy to fall off the phase change materials.A few people have prepared phase change temperature regulating fiber by filling hollow fiber to improve its durability,but because of the poor spinnability of fiber after filling phase change material,it is difficult to continue processing into textiles.Kapok fiber is a kind of natural plant fiber with 80% ? 90% porosity,which is an excellent material for preparing thermal textiles.In order to make up for the shortcomings of spinning method and post-finishing method,this paper takes kapok blended yarn as raw material and fills the kapok fiber middle cavity with PCM material.Combining the temperature regulation function of PCM material and the advantages of kapok fiber middle cavity warmth,kapok fabric with durable PCM temperature regulation function is developed.The specific research contents are as follows:(1)Kapok/cotton blended yarn and fabric with the function of phase change temperature regulation were prepared by using phase change microcapsule as temperature regulating material and kapok/cotton blended yarn as carrier.Different mass fractions of phase change microcapsules(10%,15%,20%,25%,30%),different adhesive mass fractions(1%,3%,5%,7%,9%),different impregnation temperatures(20?,30?,40?,50?,60?)and different drying temperatures(90?,100?,110?,120?,130?)were discussed by control variable method on the fabric square meter weight,phase change temperature adjustment performance and microcapsule adhesion.It was found that the optimum impregnation conditions of kapok blended yarn under different factors were as follows: mass fraction of microcapsule 25%,mass fraction of adhesive 7%,impregnation temperature 30? and drying temperature 100?.(2)By changing the raw material and finishing process,the preparation of the four different kinds of fabrics,1# ordinary cotton fabrics,2# respectively phase change temperature cotton fabrics,3# and 4# phase change temperature phase change thermal control cotton fabric pad fabric,and the surface morphology of the fabric,DSC curve,breathable moisture permeability,exposure to changes in temperature and water resistance are analyzed.The results show that the finishing effect of fabric 2# and fabric 3# is similar,but the washable performance of fabric 2# is better than that of fabric 3# because the phase change microcapsules on fabric 2# can enter the middle cavity of kapok fiber.The finishing effect and washing resistance of fabric 2# and 3# are better than that of fabric 4#,which proves that yarn finishing has better temperature adjustment effect than the phase change temperature adjusting fabric made by fabric dip rolling,and yarn finishing can improve the washing resistance.(3)With the help of Ansys software,the numerical model of the phase-change temperature regulating kapok fabric prepared in the previous paper was constructed,and the cooling process of the fabric was simulated,and the influence mechanism of phase-change heating on the heat transfer performance of the fabric was analyzed.The results show that the average temperature difference of 1# and 2# fabrics is 0.615? and 0.302? respectively,and the average difference rate is 2.72% and 1.20%,respectively.The simulation and experimental results are close,which proves that the model is correct.Based on this model,the relationship between different ambient temperature,fabric thickness,wind speed and fabric heat transfer performance was studied.The analysis shows that the initial temperature of the fabric is 39?,and the temperature of the fabric with thickness of 0.75 mm,1.5mm,3mm,6mm and 12 mm is 21.2?,22.0?,25.3?,28.1? and 34.1?,respectively,when the simulation is carried out for 800 s.The larger the fabric thickness is,the slower the temperature decreases with time.When the ambient temperature is-20?,-10?,0?,10?and 20?,the fabric temperature decreases to 8.3?,14.3?,21.3?,25.9? and 27.9? in turn.The ambient temperature has a great influence on the heat dissipation of the fabric.The lower the ambient temperature is,the faster the fabric temperature decreases.When the wind speed is 0.1m/s,2m /s,4m /s,6m /s and 8m/s,the temperature of the fabric is 27.9?,25.5?,24.8?,24.3? and 24.3?,respectively.Under the condition of wind,the convective heat transfer on the surface of the fabric is larger,and the temperature drops faster. |
PDF Full Text Request