Preparation And Properties Of PA6/RSSiO₂@PEG Phase Change Fiber

Phase change material（PCM）is a common class of latent heat storage materials,which can use their heat absorption and exothermic behavior to achieve thermal storage and temperature regulation function,phase change fiber is a new type of functional fiber material with intelligent temperature regulation ability obtained by combining PCM with fiber,which can be used in the field of civil clothing to improve the comfort of clothing fabrics and has ideal application prospects.In this paper,a mesoporous silica nanoparticle（RSSiO₂）is synthesized as a carrier and PEG is selected as the phase change medium to prepare a new shape-stabilized phase change composite material,explore its application in melt-spun PA6 fibers,analyze the spinnability of the blended material and realize large-scale melt-spinning to produce PA6-based composite phase change fibers with ideal temperature regulation and mechanical strength to meet the requirements of civil fibers.The main studies are as follows:1.The synthesis of large pore capacity RSSiO₂,the preparation and characterization of RSSiO₂@PEG composites.The experimental scheme was optimized to obtain the ideal structure of RSSiO₂ with pore size and specific surface area of 27.3 nm and 320 m²/g,respectively,followed by the preparation of RSSiO₂@PEG composites by rotary evaporation with a maximum PEG loading of 70 wt%,the melting enthalpy reached 96.2 J/g,and the temperature regulation time reached 569 s and 449.6 s in the winter and summer temperature environments simulated by the hot and cold table,showing the ideal thermal storage,temperature regulation capability,and good thermal/service stability.2.Exploration of the spinnability of PA6/RSSiO₂@PEG₇₀ phase change fibers for melt spinning.PA6-based composite functional masterbatches with different mass ratios were prepared by a twin-screw extruder,and the viscoelastic behavior of the blended material was first tested using a flat plate rheometer.As the phase change filler content increased,the agglomeration effect within the material became more and more obvious and the spinnability gradually deteriorated,especially when the mass fraction of phase change filler reached 20%,the agglomeration effect jumped up and the processing performance deteriorated sharply.The phase change fiber monofilaments were then extruded by a single-screw extruder and the performance parameters of the fibers were tested.The results showed that the phase change material within the fibers was uniformly dispersed and no significant agglomeration occurred.During the extrusion process,RSSiO₂@PEG₇₀ composites showed good spinnability at a mass fraction of up to 15%,which was consistent with the results of the flat plate rheological tests.In terms of phase change properties,the melt enthalpy of 15%PCF reached 10.87 J/g,which has a more desirable enthalpy value.This chapter provides a theoretical and practical basis for the realization of melt spinning of PA6-based phase change fibers.3.Melt spinning of PA6-based composite phase change fibers and their properties.PA6-based composite phase change fibers with different mass ratios were prepared using a melt spinning machine to investigate the effect of phase change filler content on fiber properties.The experimental results showed that the phase change functional filler did not show large scale agglomeration in the PCF and exhibited good dispersion;the mechanical properties of the fibers changed after hot drawing at different multiplicity ratios,with PCF-20 showing a significant decrease in the highest drawing ratio and poor fiber formation.PCF-15（3.5）and PCF-20（2.5）showed the highest breaking strength of 2.13 cN/dtex and 1.06 cN/dtex,and the DSC test showed the highest phase change enthalpy of 17.53 J/g for PCF-20 and 12.28 J/g for PCF-15;the fabric woven can provide a temperature buffer time of 492 s in a high temperature environment（70 ℃）and 121 s in a low temperature environment（0 ℃）for 121 s.Finally,the thermal stability and cycle stability of PCF-15 was demonstrated by thermal stability tests.As a result,PA6-based phase change fibers with desirable phase change properties,temperature regulation and mechanical strength were prepared by melt spinning.