title: Enhanced reaction kinetics and impact strength of cyanate ester reinforced with multiwalled carbon nanotubes.
abstract: In this work, the effect of multiwalled carbon nanotubes on the properties of a unique, low viscosity bisphenol E cyanate ester (BECy) resin is characterized during various stages of nanocomposite preparation. The effect of surface functionalization, with nanotubes containing hydroxyl groups (OH CNTs) and carboxylic acid groups (COOH CNTs), on the rheological, cure, thermal, and impact properties of the nanocomposite properties are also examined. Based on rheology measurements prior to cure, the unfunctionalized nanotube suspensions are found to exhibit the highest viscosity and the most dramatic shear thinning behavior. Cure characterization using differential scanning calorimetry (DSC) reveals that the nanotubes catalyze the cure of BECy and the OH CNTs exhibiting the most dramatic catalytic effect. The DSC data is well described by an nth order autocatalytic model. The impact strength of fully cured BECy is found to increase by 91% and 63% upon incorporation of 1 wt% COOH and OH CNTs, respectively. While incorporation of 1 wt% unfunctionalized nanotubes results in an 8 degrees C decrease in the glass transition temperature (T(g)) of BECy, chemical functionalization greatly mitigates the magnitude of the reduction.
authors.affiliation: Department of Materials Science and Engineering, Iowa State University, Ames IA 50011, USA.
authors.forename: Prashanth
authors.initials: P
authors.lastname: Badrinarayanan
authors.forename: Josh
authors.initials: J
authors.lastname: Leonard
authors.forename: Michael R
authors.initials: MR
authors.lastname: Kessler