Synthesis of polyurethane microPCMs containing n-octadecane by interfacial polycondensation: Influence of styrene-maleic anhydride as a surfactant

A series of polyurethane (PU) microcapsules containing a phase change material (PCM) of n-octadecane was successfully synthesized by an interfacial polymerization in aqueous styrene-maleic anhydride (SMA) dispersion with diethylene triamine (DETA) as a chain extender reacting with toluene-2,4-diisocyanate (TDI). Thermal analysis (TGA and DTA), FTIR, SEM, TEM measurements have been applied to analyze the properties of samples. The average diameter of microPCMs is in the range of 5–10 μm under the stirring speed of 4000 rpm. Results showed that PU-shell regularly fabricated with the influence of SMA varied with weight ratio from 1.0 to 4.0% on diameter, encapsulated ratio, release properties and thermal stability. Also, the particle growth was controlled by the amount of SMA from measuring the shell thickness by SEM. However, the DSC curves of microPCMs samples prepared by 1.0, 2.0 and 3.0 wt.% of SMA indicated the thermal absorb-release property was not affected by the amount of the dispersant.