Surface modification by microencapsule coating and grafting to prepare high hydrophilic polytetrafluoroethylene micropowder

Abstract Due to the hydrophobic nature and high gravimetric density, it is very difficult to obtain water dispersible polytetrafluoroethylene (PTFE). In this work, high hydrophilic PTFE microparticle was successfully prepared by grafting poly(acrylic acid) MAA and BA onto the surface of PTFE micropowder via an in-situ polymerization of melamine formaldehyde resin (MFR) coating processing method. The functional groups and surface microstructures of the MFR/acrylate modified PTFE micropowder were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Scanning electron microscopy (SEM), the hydrophilic performance was characterized by water contact angle measurement. The results revealed that the hydrophilicity of the PTFE micropowder was greatly enhanced by grafting of the MFR/acrylate complex systems, and the contact angle decreased from 132.8° for pristine PTFE to 73.2° for sample of MFR1PTFE60MAA5BA2.5. The obtained micropowder could be well dispersed in water to form homogeneous suspension with high stability. Compared with the other methods to improve the hydrophilicity of PTFE microparticle, furthermore, this microcapsule grafting method is more convenient and efficient, which could promote the application of PTFE micropowder in waterborne coating fields.