Preparation of phenolic hollow microspheres via in situ polymerization

Background: Phenolic hollow microspheres with a closed structure have a set of outstanding thermal characteristics. In the work reported here, a facile method is introduced to fabricate phenolic closed hollow microspheres by in situ polymerization in oil-in-water emulsion. Although in situ polymerization has been widely used to prepare hollow microspheres, it has not been utilized for the preparation of phenolic hollow microspheres. Results: The average particle size of the produced microspheres was about 500 μm. Fourier transform infrared spectroscopy indicated that the phenolic microspheres were partially cured during preparation and a significant number of hydroxymethyl groups remained in the microspheres. Thermogravimetric analysis showed that the thermal decomposition temperature of the phenolic hollow microspheres was 420 °C, and residual weight at 800 °C was 62%. Differential thermal analysis showed that the glass transition temperature of the phenolic hollow microspheres was 200 °C. Conclusion: Using in situ polymerization, high thermal performance phenolic hollow microspheres are produced. The resultant product possesses a satisfactory closed hollow structure with controlled morphology.