Dynamic mechanical properties of a TiO 2 ‐filled crosslinked epoxy resin from 20–90°C.

Dynamic mechanical measurements were made with a torsional pendulum of a TiO   2   −filled epoxy polymer (crosslinked with hexamethylene diamine) over a temperature range from 20–90°C., at filler concentrations of 0–40 wt.‐%. The second‐order transition temperature ( T g ) was raised as the filler content increased. The behavior of TiO 2 filler results in a long‐range immobilization of the highly crosslinked system with resultant increases in shear modulus (higher G ′) as well as decreased capacity for energy dissipation (lower damping factor). The out‐of‐phase modulus ( G ″) increased with filler content as well. The magnitudes of the slope parameters H r (representing G ′ data above T g ) and H g (representing G ′ data below T g ) decreased with greater filler content. The possibility is set forth that the TiO 2 filler causes a different distribution of mobility around the nitrogen junction as well as a change in the effective number of CH 2 units between crosslinks.