Resole-type phenol resin-clay nanocomposites have been prepared successfully by melt compounding phenol resin with organophilic clay. In the resulting phenol resin- clay nanocomposite, the silicate layers of the clay were exfoliated and dispersed as monolayers. The nanocomposite exhibited higher long-term heat resistance when compared with unmodified phenol resin. It was surmised that the silicate layers of the clay acted as barriers to oxygen penetration into the resin, as the degree of heat degradation of the nanocomposite was much lower than that of the straight phenol resin. (c) 2006 Wiley Periodicals, Inc.