| Abstract: | Phenol–formaldehyde (PF) resins modified with nanosized copper particles were synthesized by an in situ polymerization process. X‐ray diffraction analysis and transmission electron microscopy revealed that the copper particles in the resulting PF resins had a spherical geometry with a size of 30–60 nm in diameter, and there were about 5% of the particles which were agglomerated. The thermal properties of the resulting PF resins were investigated using TGA. It was found that the copper nanoparticles markedly improved the thermal stability of the PF resins at lower temperatures. The initial decomposition temperature of the modified PF resins could be increased by 47 °C compared to unmodified resins. However, the copper nanoparticles increased the rate of degradation of the PF resins at elevated temperatures. The effects of copper nanoparticles on the thermal properties of the PF resins when used as binders for friction materials are beneficial. The toughness of the resulting PF resins was also studied. The results revealed that copper nanoparticles obviously improved the brittleness of the PF resins. The impact strength of the modified PF resins was increased by 66.6% compared to unmodified resins. Copyright © 2006 Society of Chemical Industry |
