Study On Dyeing Properties Of PAN Fibers Containing Double Shell Microencapsulated Phase Change Materials

In this thesis, thermal properties of Polyamide Paraffin microencapsulated phase change materials (MEPCM) were researched. Double-shell MEPCM was prepared by the emulsion polymerization method using butyl acrylate as monomer. The effects of preparation conditions (monomer concentration, reaction time, reaction temperature, etc.) on the shape, diameter and yield of double-shell were researched. Their formation, structure, and thermal stability were characterized by Scanning Electron Microscopy, Fourier Transform Infrared Spectrometer, Microcomputer differential thermal balance. MEPCM were added to polyacrylonitrile (PAN) in a NaSCN aqueous solution, and thermo-regulated PAN fibers were prepared via wet spinning. The effect of MEPCM content, surfactant type, spinning solvent, solid content, process conditions on thermal properties on the spinnability of spinning solution, mechanical property and thermal property of thermo-regulated PAN fibers were studied. Dyeing propertys of cationic dyes, direct dyes, disperse dyes and acid dyes on thermo-regulated PAN fibers were studied.The results showed that, when single-shell MEPCM were coated, the diameter increased with increasing the content of butyl acrylate and reaction time, and formation deteriorated with increasing the content of butyl acrylate and reaction time. The apparent viscosity of spinning solution decreased, the properties of storing heat and adjusting temperature and linear density increased, density, breaking tenacity and extension decreased with increment of MEPCM content. The fiber mechanical properties improved for adding surfactant, the fiber breakage rate, drafting multiple were improved by adding non-ionic surfactant. Different organic solvent spinning could be used when different types of MEPCM were added. The same process conditions, using DMSO as a spinning solvent, the viscosity decreased and mechanical properts deteriorated, while using NaSCN as spinning solvent, the dry MEPCM should not be used as functional additives. The fiber strength increased and elongation at break decreased with the solid content and the spinning pressure increases. Compared with single-shell MEPCM, adding double-shell MEPCM obtained fiber has excellent mechanical properties. Dyeing thermo-regulated PAN fibers, results indicated that the isotherm of thermo-regulated PAN fibers was similar to that of PAN fibers when dyed with cationic red5GN at the same temperature, followed the Langmuir sorption mechanism. The partition coefficient, dye saturation value and dyeing affinity increase with the rise of the dyeing temperature. The differences in the partition coefficient, dye saturation value and dyeing affinity at low temperature between thermo-regulated PAN fibers and PAN fibers were bigger than high temperature. After high temperature dyeing at90℃, the fiber remains high enthalpy value, which can withstand the processing conditions of the cationic dye. The adsorption isotherm of other three dyes thermo-regulated fiber belongs to the Nernst model. Under the same dyeing situations, cationic red5GN balance dye uptakes of thermo-regulated PAN fibers were higher than common PAN fibers. Dyeing rate constants increased with increment of MEPCM content and dyeing temperature, half dyeing time and balance dye uptakes decreased with the increment of MEPCM content. The dyeing properties of fibers were improved with adding MEPCM, because that MEPCM could make the dye diffusion and adsorption process in the fiber internal easier, dye at low temperature. This research provides theoretical and practical basis for producing the excellent mechanical property and higher temperatures themo-regulated fiber.