Abstract
The ultrasonic attenuation of polystyrene derivatives: o-(CH 3, Cl, Br), m-(Br), p-(Br) and α-methyl, has been investigated as a function of temperature and frequency. At least two relaxation processes were needed to account for the ultrasonic spectra and the related thermodynamic parameters have been calculated. The position and steric hindrance of the substituent have no significant effect on the activation energy but affect the enthalpy difference corresponding to the highest frequency relaxation process. The results obtained permit comparison of the intramolecular mobility of the monosubstituted polystyrenes with that of polystyrene. Poly(α-methylstyrene) behaves very much like polystyrene. Intramolecular mobility appears higher in poly( m-bromostyrene) than in p- or o-substituted polymers. Finally, the shift of the ultrasonic spectra of o-substituted polystyrenes to low frequencies is all the stronger as the substituent is bulky.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
