In Situ Generation of Ammonia: an Efficient Catalyst for the Synthesis of Phenol-Aniline-Formaldehyde Resol Resin

A novel method developed for the synthesis of resol based phenol-aniline-formaldehyde (PAF) resins by in situ generation of ammonia using magnesium hydroxide and ammonium chloride as reagents in the presence of phenol, aniline and formaldehyde. The synthesized PAF resol resins were characterized by IR, NMR spectroscopic methods, thermal stability by thermogravimetric analysis (TGA) and thermal properties by differential scanning colorimerty (DSC). Free phenol and free aniline of PAF resins were determined using gas chromatography and also these resins characterized for elemental analysis, inherent viscosity, molecular weight and gel time. DSC results illustrated that the glass transition temperatures of PAF resins exhibited in the range of 72-110 °C, whereas TGA results depicted that the thermal stability of the PAF resins revealed in the range of 516-548 °C. In situ generation of ammonia showed higher thermal stability and lower content of free phenol and free aniline in PAF resin.

Keywords:

Phenol-aniline-formaldehyde resins , in-situ , Ammonia , resol , thermal properties