| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2000: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
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| Research Abstract |
Electron spin resonance (ESR) spectroscopy is a very useful tool to investigate fundamental processes in radical polymerization systems, because information on structures, concentrations, and dynamics of paramagnetic species can be directly obtained from ESR measurements. However, ESR spectroscopy was considered to be difficult to acquire kinetic data owing to the experimental limitation. Fortunately, we found that well-resolved ESR spectra of the propagating radicals of vinyl and diene compounds could be observed by a conventional CW-ESR spectrometer. Accordingly, kp values for the polymerization of vinyl or diene compounds were estimated on the basis of experimental results obtained from ESR measurement, and compared the obtained k_p values and kinetic parameters with those estimated by PLP method.
Propagation rate constants (k_p) for the free radical polymerization of n-butyl methacrylate (nBMA) in toluene solution were measured by ESR spectroscopy in the temperature range from-30 to 90 ℃. The Arrhenius parameters A and E_a were estimated to be (3.40±0.4) x 10^6 M^<-1> s^<-1> and (22.0±1.0) kJ/mol, respectively., which were in fair agreement the corresponding data obtained from the pulsed laser polymerization (PLP). Reestimation of kp values for vinyl monomers was performed by ESR spectroscopy. Moreover, Well-resolved electron spin resonance (ESR) spectra of propagating radicals in radical polymerizations of vinyl chloride have been detected for the first time under irradiation.
The value of k_p for the radical polymerization of vinyl chloride was also estimated by ESR spectroscopy. Value of k_p for vinyl chloride was (5400±1500) M^<-1> s^<-1> at 25℃, which is in agreement with one of those obtained by the rotating sector method.
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