ISSN:
0887-624X
Keywords:
α-ethyl β-hexafluoroisopropyl itaconate
;
radical polymerization and copolymerization
;
ESR spectrum
;
rate constants of propagation and termination
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The synthesis of α-ethyl β-hexafluoroisopropyl itaconate (EFiPI) was performed. The polymerization of EFiPI initiated with dimethyl 2,2′-azobisisobutyrate (MAIB) was investigated kinetically in benzene. The polymerization rate (Rp) was expressed by Rp = k[MAIB]0.5[EFiPI]2.0 at 50°C. The overall activation energy of the polymerization was calculated to be a low value of 57.38 kJ/mol. Rate constants of propagation (kp) and termination (kt) were estimated under different polymerization conditions, using the ESR-determined concentrations of the propagating polymer radical. The increase in kp value (3.3-6.0 L/mol s) and the decrease in kt value (0.94-3.7 × 105 L/mol s) with monomer concentration are mainly responsible for the high dependence of Rp on the monomer concentration. Activation energies of initiation (Ei), propagation (Ep), and termination (Et) were also determined: Ei = 130.7 kJ/mol, Ep = 18.0 kJ/mol, Et = 57.4 kJ/mol. The large apparent activation energy of termination is a main origin of low overall activation energy of the polymerization. Thermal behavior of the resulting poly(EFiPI) was investigated by differential scanning calorimetry (DSC) and dynamic thermogravimetry (TG). Copolymerization of EFiPI (M1) with St (M2) was also examined at 50°C in benzene. The following copolymerization parameters were obtained according to the curve-fitting method: r1 = 0.05, r2 = 0.46, Q = 0.46, e = +1.14. Using these results, the rate constants of cross propagations in the copolymerization were estimated. © 1995 John Wiley & Sons, Inc.
Additional Material:
15 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pola.1995.080330506
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