Low cracking ratio of paraffin microcapsules shelled by hydroxyl terminated polydimethylsiloxane modified melamine-formaldehyde resin

Premature rupture caused by the high hardness and brittleness of melamine-formaldehyde (MF) resin has been a problem of MF microcapsules during synthesis and processing. In this work, we successfully encapsulated paraffin with hydroxyl terminated polydimethylsiloxane(HTPDMS) modified MF and the effects of HTPDMS dosage on the mechanical properties of MF were investigated. The FTIR spectra indicated that HTPDMS modified MF shell was successfully synthesized. SEM images and PSD results showed that the obtained microcapsules were spherical with smooth surface and an average diameter of 13 mu m. The XRD results indicated that the HTPDMS modified MF shell performed better mechanical toughness, resulting in the cracking ratio of the modified microcapsules as low as 13.8%. In addition, the HTPDMS modified MF microcapsules exhibited better encapsulation property and the paraffin content of the microcapsules reached 76.8%. Meanwhile, these microcapsules showed an excellent thermal stability.