Thermal Properties. — Thermal properties of the samples were determined using a TA Instruments, Inc. (Wilmington, DE) DSC Q2000 differential scanning calorimeter. Samples were prepared in aluminum hermetically sealed pans, equilibrated at 100 8C for 1 min, cooled, and subjected to a temperature ramp at 10 8C/min from 150 8C to 100 8C. Glass transition (Tg) at the inflection point was recorded.