Thermal properties and stability of boron-containing phenol-formaldehyde resin formed from paraformaldehyde

A boron-containing phenol-formaldehyde resin (BPFR) was synthesized from boric acid, phenol and paraformaldehyde. The structure change of BPFR during curing was studied by Fourier-transform infrared (FTIR) spectroscopy. The glass transition temperatures (T-g) were determined by differential scanning calorimetry (DSC) and torsional braid analysis (TBA). The thermal degradation of BPFR was studied by FTIR and thermogravimetry analysis (TGA). The results indicate that the degradation of BPFR begins with the breaking of B-O bonds. The TGA results show that the dynamic thermal degradation of BPFR appears as four reaction stages in nitrogen and three in static air. The kinetic analysis results show that the reaction follows a first order mechanism to the second and third stages in air, and first order to the second stage and third order to the third and fourth stages in nitrogen. (C) 2002 Published by Elsevier Science Ltd.