2.5. Thermal properties
The thermal behaviors of the graft copolymers were characterized using a DSC7 (Perkin Elmer, USA) under nitrogen atmosphere at a heating rate of 10 °C/min. A change of heat flow in the second heating scan from −90 to 170 °C was recorded after having removed the material heating history in the first heating scan. The Tg values were taken at the inflection point, i.e. at the half-width of the baseline shift. TGA analysis was performed using a TA Instruments SDT Q600 thermal analyzer. A sample of 10–20 mg was placed in a ceramic cup and analyzed under nitrogen atmosphere with a gas flow rate of 100 mL/min, at a heating rate of 20 °C/min from room temperature to 600 °C. The initial temperature of weight loss (Ti), temperature at peak of the 1st derivative weight loss (Tp) and final temperature of weight loss (Tf) were recorded.