PET granules and three different nano-silica particles were
dried in an oven for 24 h at 110 8C, prior to the melt processing.
Each nanocomposites was prepared by mixing in a C.W. Brabender
PL2000 Plasticorder from Germany. The mixing temperature was
kept at 255 8C in order to ensure proper viscosity for the mixing.
The rotation speed was set at 60 rpm for 20 min. The total weight
of material per batch was 40 g. The content of each nano-silica
particle in the matrix was ensured to be 5% by weight (wt%).
Specimens to be tested were further processed by the aid of a
laboratory press at a pressure of 40,000 psi. The temperatures of
both upper and lower plates of the press were kept at 260 8C.