Highly stable hexamethylolmelamine microcapsules containing n‐octadecane prepared by in situ encapsulation

A systematic study has been carried out to investigate the effect of formaldehyde‐to‐melamine molar ratio varying from 2.5 to 8, core‐to‐wall ratio from 1 to 4 and curing conditions used during the encapsulation process on the properties of microcapsules that contain n‐octadecane as the core material and melamine‐formaldehyde as the wall material. The microcapsules so obtained were characterized for their core content, encapsulation efficiency, thermal, and solvent stabilities. Using the modified encapsulation process with a formaldehyde‐ to‐melamine ratio of 8 and core‐to‐wall ratio of 2, microcapsules with a high core content of (70%) and a heat storage capacity of >160 J/g could be obtained. The capsules were found to be stable upto a temperature of 100°C and also stable to cyclohexane wash. A thermoregulated fabric was also prepared by coating the capsules on a cellulose‐polyester fabric to give a heat storage capacity of >100 J/g.