Preparation And Properties Of Phase-change Functional Fibers

Phase change materials(PCM)is a functional material that absorbs or releases a large amount of latent heat to maintain its temperature at a relatively narrow range by changing its phase state when the environment temperature changes.It is widely used in the field of intelligent textile because of its low cost,high thermal efficiency,reusability and high energy storage.The phase change material is added to the fiber to prepare the energy storage temperature-regulating fiber,which can automatically absorb or release heat according to the change of the external temperature to reduce the temperature fluctuation of the skin surface,thereby ensuring the comfort of the human body.Among many solid-solid phase change materials and solid-liquid phase change materials,paraffin wax has been a research hotspot in the field of energy storage thermostat fiber due to its high phase change latent heat,excellent thermal stability,abundant source and low price.However,the existing phase change fibers have problems such as poor processability,complicated preparation process,low yield,and difficulty in packaging of phase change materials,In order to solve this problem,we used the high temperature phase change wax as the phase change medium,and prepared the PW/PP masterbatch and PW/PE masterbatch by blending with polypropylene(PP)and polyethylene(PE)respectively,and then we used PW/PP masterbatch as the skin layer,PW/PE masterbatch is the core layer,and obtained the core-sheath energy storage and temperature-regulating fiber by melt spinning,and we used cotton yarn as the warp yarn,and the phase change fiber is used as the weft yarn.We also obtained three fabrics with the same basic parameters by the weaving mechanism.The shear rheology and extensional rheological properties of PW/PP masterbatch were analyzed by two-column capillary rheometer,and the crystallization properties and morphology were also discussed.The phase change fibers were passed through differential scanning calorimeter,thermogravimetric analyzer,scanning electron microscope and yarn.The strength meter tests its energy storage temperature regulation performance,thermal cycle performance,thermal stability,microscopic morphology and mechanical properties,as well as through fabric density analysis mirrors,fabric thickness gauges,differential scanning calorimeters,universal testing machines,and heat.The constant analyzer,the fabric gas permeability meter and the capillary effect tester respectively test and analyze the density,thickness,temperature regulation effect,mechanical properties,thermal conductivity,gas permeability and water conductivity of the fabric.The main conclusions are as follows:1.The addition of PW does not change the flow type of PP,but it will reduce the flow resistance of the melt.With the increasing of PW mass fraction,the shear stress,shear viscosity,shear activation energy,extensional stress,extensional viscosity and the extensional flow activation energy is gradually reduced.The thermal degradation rheology experiment showed that the sample have good thermal stability,and the addition of PW had no effect on the thermal stability of PP.The melt uniaxial tensile test proves that the melt has good tensile properties,but the addition of PW causes the draw ratio of PP and the melt strength to decrease to some extent.The initial decomposition temperature of the melt has a significant increase compared with pure PW.So choosing the proper melting temperature can make the phase change wax/polypropylene blend have good thermal stability and meet the requirements of melt spinning.The addition of PW will reduce the crystallization performance of PP.As the additive content increases,the crystallization temperature of the composite decreases,the crystallinity decreases,and the degree of supercooling increases.2.The composite fiber sheath core structure is obvious,the skin layer is well wrapped,and the PW has no leakage phenomenon.With the increasing of the core material content,the composite fiber phase change enthalpy gradually increases,the initial thermal decomposition temperature gradually decreases,and the elongation at break gradually increases.The breaking strength is gradually reduced,and the composite fiber with a sheath-core ratio of 5:5 can be intelligently tempered in the range of 25～32℃ and 24～18 ℃,and the corresponding endothermic and exothermic enthalpy reach 7.83 J/g and 7.74 J/g,and it has good thermal cycle stability,its initial thermal decomposition temperature,elongation at break and breaking strength are 217.19℃,81.3%and 1.14 cN/dtex respectively.3.The test of fabric temperature regulation performance shows that the fabric has temperature regulation effect in the range of 25～35℃ and 23～15 ℃,and as the mass fraction of weft core material increases,the melting enthalpy and crystallization enthalpy of the fabric gradually increase,and the weft yarn is leather.The melt enthalpy and crystallization enthalpy of the core ratio of 5:5 reached 3.68 J/g and 3.52 J/g,respectively,and it has good phase change reversibility.The thermal conductivity test of the fabric shows that the thermal conductivity of the thermostat fabric decreases with the increase of temperature,but the decrease is not obvious.The fabric permeability test shows that the fabrics obtained by the experiment have the same air permeability and the fabric structure is uniform.No obvious gaps and excessive appearance.The mechanical properties and water conductivity test were analyzed.As the content of weft core material increased,the elongation at break of the fabric increased,the breaking strength decreased gradually,the longitudinal wicking rate of the fabric was faster,and the wicking height was larger.