OSCILLATING DIFFERENTIAL SCANNING CALORIMETRY

W.J. Sichina, N. Nakamura, Oscillating Differential Scanning Calorimetry Software. Seiko Instr. Product Detail 5. 

The preparation of ZnO/ PS nanocomposites preceded as follows [112] First, 110 mg bare ZnO or 110 mg PMMA-grafted ZnO were added into a three-necked bottle. Then, 10 mL styrene was added into the reactor. The mixture was stirred with the aid of ultrasonic oscillation until a uniform dispersion of the ZnO particles in styrene was attained. Afterwards, 36 mg azobisisobutyronitrile (AIBN) was added into the reactor as initiator. The subsequent polymerization was conducted at 85°C for 2.5 h. Then, the obtained composites were dried under vacuum for 24 h. The differential scanning calorimetry (DSC) heating curves of neat PS, PS/ZnO (bare), and PS/ZnO (PMMA grafted) are shown in Fig. 10. DSC traces in Fig. 10a show that neat PS has a lower glass transition temperature (Tg = 87.7°C) than PS/ZnO (bare, 7 g = 97.9°C) and PS/ZnO (PMMA grafted, Tg = 95.3°C). This behavior can be explained by the restricting effect of the nanoparticles in polymer. ZnO... 

The course of conversion has already been photometrically, polarographically and barometrically recorded. The polarographic measurement, almost free of inertia, has revealed a sawtooth-shaped oscillation. Calorimetric investigation has been carried out until now only in micro calorimeters by differential thermal analysis DTA (non-isothermal) and by differential-scanning-calorimetry DSC (quasi-isothermal). The calorimetric inertia of the control systems is too large to enable the system to record correctly sawtooth-shaped oscillations, i.e. relatively abmpt changes in reaction power. The characteristic course can only be distortedly recorded. 

---