Bio-based nanocomposites by in situ cure of phenolic prepolymers with cellulose whiskers

Abstract

A series of resole-type phenolic resin-based nanocomposites, uniformly filled with cellulose nanowhiskers (CNWs), was successfully fabricated via direct solution mixing, then solvent-exchange with DMF and finally stepwise thermal curing. Dynamic mechanical analysis evidenced a moderate reinforcing effect with a minimum CNWs weight content of 5.0 wt% especially above the resin glass transition temperature (T g ). The Halpin–Kardos model provided a good description of the CNWs reinforcing effect, suggesting perhaps the contribution of whiskers/matrix interactions rather than that of whiskers/whiskers interactions. Differential scanning calorimetry (DSC) further indicated that the nanowhiskers enhanced the resin cure, resulting in a more extensive degree of cure. Finally, the CNWs were found to only slightly lower the thermal stability of PF resins. In spite of a modest reinforcing effect, it is proposed that CNWs are also interesting fillers for high modulus and high T g thermosetting resins that require high temperature cure.