Preparation and properties of PAN/phase change microcapsule composite phase change fibers by wet spinning process
The phase change microcapsule(MPCM)lotion formed by polyurea coating n-octadecane used as phase change modifier was blended with PAN to prepare spinning solutionv which was produced into PAN/MPCM composite phase change fi-bers with different MPCM content by wet spinning process.The chemical structure,particle size distribution,thermal properties and thermal stability of the MPCM lotion were analyzed.And the surface morphology,thermal properties,crystallization proper-ties,mechanical properties and thermal cycling performance of the phase change fiber were studied.The results showed that the MPCM lotion exhibited a uniform particle size distribution and an average particle size of 634.3 nm,and the phase change oc-curred at 31.4℃ and 20.3℃,with an enthalpy of phase change up to 166.0 J/g,indicating good phase change properties and good thermal stability;the phase change fibers had uniform thickness with a diameter of about 175 μm;the surface of the fibers became uneven,with obvious protruding microcapsule balls,with the increase of MPCM content;the thermal properties of phase change fibers was significantly improved,and the crystallization and mechanical properties were also improved with the increase of MPCM content;the phase change fibers had a melting temperature of 29.3℃,solidification temperature of 22.1℃,melting en-thalpy of 44.1 J/g and solidification enthalpy of 44.1 J/g when the mass fraction of MPCM was 8.7%,indicating good thermal properties,and the phase change temperature and enthalpy value after 50 thermal cycles were basically consistent with those after 1 thermal cycle,indicating good thermal cycling stability;and the phase change fibers showed a breaking strength of 0.52 cN/dtex,elongation at break of 35.01%and modulus of 1.19 GPa when the mass fraction of MPCM was 8.7%.