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With stearic acid (SA) as phase change material, waste polyacrylonitrile fiber (PAN) as framework material, N,N-dimethylformamide (DMF) as solvent, form-stable PAN/SA blends phase change materials (PCM) are prepared by solution blending process. Phase change temperature and latent heat and the thermal stability of the PAN/SA PCM are characterized using Differential Scanning Calorimetry (DSC). The structure, crystalline morphology, and thermal insulation properties of the PAN/SA PCMs are investigated using Fourier transformation infrared spectroscope (FTIR), polarizing optical microscopy (POM), and temperature-recording instrument. The FTIR and POM results show that PAN and SA are combined by intermolecular forces, and SA is homogeneous distribution in the PAN matrix. The DSC results indicate that PAN/SA PCMs have high latent heat storage capacity of more than 115J/g, the phase transition temperature and phase transition enthalpy of the PCMs increase with increasing the mass percent of SA. Cooling curve of PAN/SA PCMs show that the PCMs have good insulation properties, the soaking time is continued for about six minutes, and the thermal insulation properties remain unchanged after five and ten times of thermal cycling. The best process condition is obtained by the soaking time and orthogonal experiment.

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A kind of crosslinking copolymer as solid-solid phase change material (PCM) is synthesized by copolymerization. The scope of PCM applications is often severely limited by their heat stablility and phase transition state. The solid-solid phase change materials we obtained retain basic state during phase change transitions. The crosslinking polymer is heat stable under 300 and the latent heat of crystalline and latent heat of melting is on the average of 120 J/g and 140J/g, respectively. The property of thermal stability and heat storaged is related to crosslinking density of the gel. The property of thermal stability and high latent heat may expand the scope of PCMs applications.

A new kind of form-stable polyacrylonitrile fiber/binary of fatty acids composites as phase change materials was prepared by a solution blending process. In this material, the binary system between stearic acid and lauric acid with different components was served as latent heat storage material and polyacrylonitrile as the supporting material, N,N-dimethylformamide as solvent. Phase change temperature and latent heat and the thermal stability of the polyacrylonitrile/binary of fatty acids composites were characterized using differential scanning calorimetry. The structure, crystalline morphology, surface morphology, and thermal insulation properties of the polyacrylonitrile/binary of fatty acids composites were investigated using Fourier transformation infrared spectroscope, polarizing optical microscopy, scanning electron microscope, and temperature-recording instrument. The Fourier transformation infrared results showed that polyacrylonitrile and binary of fatty acids were combined by intermolecular forces. The differential scanning calorimetry results indicated that polyacrylonitrile/binary of fatty acids composites had high latent heat storage capacity of more than 135.8 J/g, the phase transition temperature was about 25 ı C. The photograph of polarizing optical microscopy and scanning electron microscope suggested that stearic acid and lauric acid were homogeneous distribution in the polyacrylonitrile matrix; Cooling curve of polyacrylonitrile/binary of fatty acids composites showed that its soaking time was continued for about 17.7 minutes, and the thermal insulation properties remain unchanged after more than once cycling. The best process condition was obtained by the soaking time and orthogonal experiment.