Synthesis and property of solid resol phenolic resins with high molecular weight

In this paper the solid resol phenolic resins with high molecular weight were synthesized via a two-step protocol: firstly the Novolac phenolic resins as the raw materials were prepared; then the methylolation was conducted under alkaline catalysis to get resol phenolic resins. With the molecular weight of Novolac resin increasing, the gelation time of resol phenolic resins gradually decreases (all the resins can be cured in 3 min at 150°C), while the viscosity of the corresponding resin's solution becomes higher. The dosage of HCHO increasing makes the viscosity of corresponding resin's solution higher. The influence of reaction time to resin's solution is ignorable after 12 h.