Preparation and thermophysical properties of three-dimensional attapulgite based composite phase change materials

Aiming to reveal the relationship between the thermophysical properties of shape-stabled phase change materials (PCMs) with the structure of its matrix, a series of stearic acid/three-dimensional attapulgite (SA/TATP) composite PCMs were fabricated by vacuum impregnation method using TATP as matrix, which prepared via “grafting from” method and employed attapulgite (ATP) as raw material, diphenylmethane diisocyanate (MDI) as modifying agent and amines as linking molecules. The structure of carriers, thermophysical properties of the composite PCMs were analyzed, and the relationship between the thermophysical properties of SA/TATP and characteristics of the carrier were also studied. The results indicated that the thermophysical properties of the composite PCMs were improved significantly due to the introduce of organic bonding agents and the formation of three-dimensional network in the matrix. The latent heat of SA/TATP can be up to 136.81 J/g without leakage, and the maximum thermal conductivity of SA/TATP is 0.4215 W/m•K. The melting temperature and melting latent heat of the composite PCMs degenerate with the decrease of the pore size of the carriers. The relationship between the melting phase transition temperature, melting latent heat of SA/TATP and pore size of TATP can be descripted by the Gibbs–Thomson equation. In addition, the melting enthalpy of SA/TATP is positively associated with the grafting rate of the carrier.