Preparation of the MF pre polymer: melamine and 37%
formaldehyde solution(with a mole ratio of 3:1) were put
intoathree-neckbottlewithastir.Themixturewas
adjusted to pH8–9 with 10% Na2CO3 solution , heated to
about808Candkeptatthattemperaturefor1h.TheMF
prepolymersolutionwaspreparedandreadyforuseof
themicroencapsulation.