| Abstract:Air-filled microcapsules were synthesized by in-situ polymerization using a melamine-formaldehyde (MF) resin as shell and air as core of the microcapsules, sodium dodecyl sulfate (SDS) as emulsifier. The effects of temperature, amount of emulsifier, stirring speed, amount of melamine formaldehyde resin prepolymer and pH value on the synthesis of the microcapsules were investigated. The results showed that the desired microcapsules were obtained under the following conditions : dosage of MF resin prepolymer solution 9 mL(with a mass fraction of 22.7% ), sodium dodecyl sulfate concentration 0.2%, polymerization temperture 55℃, stirring speed 1400 r/min and pH value 4.0. The microcapsules obtained under the optimal conditions were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), compression strength test and bulk density test. The results showed that the morphology of the microcapsules was hollow spherical, with an average particle size of 8.39 μm. The synthesis of wall material was completed, the compression strength was 0.52 MPa, and the bulk density was 0.05 g/cm3. The synthetic air-filled microcapsules were used to prepare bulky paper by adding to the pulp, the bulk and the whiteness of the paper increased respectively by 22.15% and 7.86% compared with the control samples. The tensile strength was lower than that of the blank paper, but better than that of the bulky paper adding the diatomaceous earth, and the bursting strength was similar to that of the blank paper. |
