화학공학소재연구정보센터
Journal of Polymer Science Part A: Polymer Chemistry, Vol.47, No.23, 6641-6654, 2009
Propagation Rate Coefficients of Isobornyl Acrylate, tert-Butyl Acrylate and 1-Ethoxyethyl Acrylate: A High Frequency PLP-SEC Study
Pulsed laser polymerization (PLP) coupled to size exclusion chromatography (SEC) is considered to be the most accurate and reliable technique for the determination of absolute propagation rate coefficients, k(p), Herein, kp data as a function of temperature were determined via PLP-SEC for three acrylate monomers that are of particular synthetic interest (e.g., for the generation of amphiphilic block copolymers). The high-T-g monomer isobornyl acrylate (iBoA) as well as the precursor monomers for the synthesis of hydrophilic poly(acrylic acid), tert-butyl acrylate (tBuA), and 1-ethoxyethyl acrylate (EEA) were investigated with respect to their propagation rate coefficient in a wide temperature range. By application of a 500 Hz laser repetition rate, data could be obtained up to a temperature of 80 degrees C. To arrive at absolute values for k(p), the Mark-Houmink parameters of the polymers have been determined via on-line light scattering and viscosimetry measurements. These read: K = 5.00 x 10(5) dL g(-1), a = 0.75 (piBoA), K = 19.7 x 10(5) dL g(-1), a = 0.66 (ptBA) and K = 1.53 x 10(5) dL g(-1), a = 0.85 (pEEA). The bulky iBoA monomer shows the lowest propagation rate coefficient among the three monomers, while EEA is the fastest. The activation energies and Arrhenius factors read: (iBoA): log(A/L mol(-1) s(-1)) = 7.05 and E-A = 17.0 kJ mol(-1); (tBuA): log(A/L mol(-1) s(-1)) = 7.28 and E-A = 17.5 kJ mol(-1) and (EEA): log(A/L mol(-1) s(-1)) = 6.80 and E-A = 13.8 kJ mol(-1). (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6641-6654, 2009