[2] (10 pts.) For a mixture of polymer and plasticizer, the fractional free volume is given...

 

Transcribed Image Text:

[2] (10 pts.) For a mixture of polymer and plasticizer, the fractional free volume is given by the following equation: f=0.025+, (T-T) +(T-T) where ap is the thermal expansion coefficient of polymer, a is the thermal expansion coefficient of plasticizer, Tgp = glass transition temperature of polymer, Tga = glass transition temperature of plasticizer, , is the polymer volume fraction and is the volume fraction of plasticizer. In general, a polymer's glass transition temperature can be easily measured but the values of thermal expansion coefficients of polymer and plasticizer are not readily available. Since the Tg of rigid PVC can be changed by adding a plasticizer, the following experiment has been carried out: The glass transition temperature of PVC is 85C. When 50 vol.% of PVC and 50 vol.% of plasticizer PX1 is mixed, the Tg of the plasticized PVC is -30C. The Tg of the plasticizer PX1 has been found to be - 100C. Calculate the volume fraction of the plasticizer to be added to PVC to change its T to -10C. [2] (10 pts.) For a mixture of polymer and plasticizer, the fractional free volume is given by the following equation: f=0.025+, (T-T) +(T-T) where ap is the thermal expansion coefficient of polymer, a is the thermal expansion coefficient of plasticizer, Tgp = glass transition temperature of polymer, Tga = glass transition temperature of plasticizer, , is the polymer volume fraction and is the volume fraction of plasticizer. In general, a polymer's glass transition temperature can be easily measured but the values of thermal expansion coefficients of polymer and plasticizer are not readily available. Since the Tg of rigid PVC can be changed by adding a plasticizer, the following experiment has been carried out: The glass transition temperature of PVC is 85C. When 50 vol.% of PVC and 50 vol.% of plasticizer PX1 is mixed, the Tg of the plasticized PVC is -30C. The Tg of the plasticizer PX1 has been found to be - 100C. Calculate the volume fraction of the plasticizer to be added to PVC to change its T to -10C.