Study of polyamine species modulating the properties of polyurea microencapsulated wall materials

Abstract This study explored the impact of various polyamines on polyurea shell performance and identified optimal candidates for high-performance microcapsules. Isophorone diisocyanate (IPDI) was combined with six polyamines (EDA, DAB, HMD, PPD, DETA, and TETA) to synthesize crosslinked polyurea shells via solvent-assisted precipitation polymerization. The polyurea coatings were characterized using ultraviolet-visible spectrophotometry, SEM, FTIR, X-ray diffraction, and thermogravimetric analysis to assess polymerization, microstructure, composition, and crystallinity. Results showed that polyamine type significantly influenced polyurea properties. Diamine-based polyureas had higher initial thermal stability, while triamine (DETA) and tetraamine (TETA) coatings exhibited better thermal degradation resistance. Tri-and tetraamine-based coatings also had uniform spherical morphologies and lower crystallinity, with TETA-derived polyurea demonstrating excellent thermal stability and low crystallinity, making it ideal for high-performance microcapsules. These findings guide the selection of suitable polyurea coatings for microcapsule applications, advancing phase change material technology.