Preparation and process optimization of polypropylene wax solid-solid phase change material

In view of the problems of difficult dispersion with emulsification and ion crosslinking of polypropylene wax phase change materials, the low degree of polymerization polyacrylic acid (PAA) grafted polypropylene wax was designed by taking advantage of the hydrophilic and easily ionized properties of polyacrylic acid (PAA) carboxyl group. The polypropylene wax emulsion was prepared by self-emulsification method. Polypropylene wax solid-solid phase change materials (PPW SS-PCMs) were prepared in aqueous medium in a short period. Firstly, the effects of acrylic acid concentration and instantaneous concentration on the self-emulsification ability of PP wax (PPW) graft products were investigated by means of infrared spectrometer, nuclear magnetic resonance spectrometer and scanning electron microscope. Then, the crystallization properties and thermal stability of PPW SS-PCMs and PPW SS-PCMs were tested and analyzed by polarizing microscope, X-ray diffrotometer, differential scanning calorimeter and thermogravimetric analyzer. The results show that the enthalpy of phase change materials decreases with the increase of acrylic acil (AA) content as the mass ratio of AA increases. In a certain range, the self-emulsification ability of modified PPW can be improved by increasing the instantaneous concentration of AA, and the amount of fixed components can be reduced. When the mass ratio of AA∶ PPW∶BPO was 0.36∶1∶0.05 and the drop acceleration rate was 9mL/min, the crystallization temperature, enthalpy and energy storage efficiency of the prepared PPW SS-pcms were 52.46℃, 53.61J/g, 81.26%, and has good thermal stability. © 2023 Chemical Industry Press. All rights reserved.