Melt Processing
Reactions were carried out in a Brabender batc mixer, (model PL2000) on predried materials under nitrogen atmosphere at 60 rpm. Bowl temperature was set at 280°C. Pre-weighed dried PET pellets were first added in the intensive mixer and after melting the modifier was added, approximately 5-6 minutes later. Temperature and torque were continuously monitored. Mixing continued for an additional 2 to 10 min time period depending on the particular system.0.1 wto/o of Sb,03, added in some runs in attempts to
prevent further torque decrease through its expected catalytic effect, produced no apparent differences. PET
pellets in the absence of modifiers were also run for
15 minutes as controls. Details on mixing times and
sequence of addition are included in Tables 3-5. In
the representation of the total mixing time, modifiers
and Sb203 were added after the completion of the first
and the second time interval, respectively.