The Arrhenius parameters of the propagation rate coefficient for two linear methacrylates, two branched methacrylates, and two branched acrylates are determined via the pulsed laser polymerization–size exclusion chromatography (PLP-SEC) method. The Mark–Houwink–Kuhn–Sakurada parameters of these polymers are additionally determined via multidetector SEC of narrowly distributed polymer samples obtained through fractionation, allowing for a correct SEC calibration in the PLP-SEC experiment. The data obtained for stearyl methacrylate (SMA, A = 3.45 (−1.17 to +4.46) × 106 L·mol–1·s–1; E a = 21.49 (−1.59 to +1.90) kJ·mol–1) and behenyl methacrylate (BeMA, A = 2.51 (−0.80 to +3.06) × 106 L·mol–1·s–1; E a = 20.52 (−1.43 to +1.85) kJ·mol–1) underpin the trend of increasing k p with increasing ester side chain length. Propylheptyl methacrylate (PHMA, A = 2.83 (−0.82 to 3.15) × 106 L·mol–1·s–1; E a = 21.72 (−1.20 to +1.64) kJ·mol–1) and heptadecanyl methacrylate (C17MA, A = 2.04 (−0.66 to +1.71) × 106 L·mol–1·s–1; E a = 20.72 (−1.42 to +1.38) kJ·mol–1) can be described as a family of branched methacrylates jointly with isodecyl methacrylate and ethylhexyl methacrylate (both published previously), resulting in joint Arrhenius parameters of A = 2.39 (−0.51 to +0.84) × 106 L·mol–1·s–1 and E a = 21.16 (−0.78 to +0.76) kJ·mol–1. In addition, the corresponding branched acrylates are studied applying high-frequency PLP at a 500 Hz laser repetition rate, resulting in Arrhenius parameters of A = 1.05 (−0.42 to +2.81) × 107 L·mol–1·s–1 and E a = 16.41 (−1.99 to +2.42) kJ·mol–1 for propylheptyl acrylate (PHA) and A = 8.15 (−2.83 to +10.3) × 106 L·mol–1·s–1 and E a = 14.66 (−1.49 to +1.66) kJ·mol–1 for heptadecanyl acrylate (C17A).

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, kp. 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‐Tg 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 °C. To arrive at absolute values for kp, the Mark‐Houwink parameters of the polymers have been determined via on‐line light scattering and viscosimetry measurements. These read: K = 5.00 × 105 dL g−1, a = 0.75 (piBoA), K = 19.7 × 105 dL g−1, a = 0.66 (ptBA) and K = 1.53 × 105 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 EA = 17.0 kJ mol−1; (tBuA): log(A/L mol−1 s−1) = 7.28 and EA = 17.5 kJ mol−1 and (EEA): log(A/L mol−1 s−1) = 6.80 and EA = 13.8 kJ mol−1. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6641–6654, 2009

The Arrhenius parameters of the propagation rate coefficient, k p, are determined via the IUPAC recommended pulsed laser polymerization–size exclusion chromatography (PLP-SEC) method for two linear alkyl acrylates (stearyl and behenyl acrylate), four branched alkyl acrylates (isononyl (INA-A), tridecyl (TDN-A and TDA-A), and henicosyl acrylate (C21A)), and two branched alkyl methacrylates (tridecyl methacrylates (TDN-MA and TDA-MA)) in bulk. Furthermore, the above stated acrylates and heptadecyl acrylate (C17A) were studied in 1 M solution in butyl acetate (BuAc). On the basis of such a wide data basis in combination with the already literature known data of relatives of the herein investigated monomers, we are able to identify and extend global trends and family type behavior for the propagation rate coefficients of a wide array of alkyl (meth)acrylates. In order to ensure a valid SEC evaluation, the polymer specific Mark–Houwnik–Kuhn–Sakurada (MHKS) parameters are determined for each of the polymers, via multidetector SEC analysis (multi angle laser light scattering (MALLS) in combination with differential viscosimetry (Visco) and refractive index (RI)) of narrowly distributed polymer samples obtained via fraction with a preparative SEC column. By employing further physicochemical polymer specific data (e.g., glass transition temperatures (T g)), we provide a hypothesis for the reported trends and family type behaviors: (i) the steady increase of k p with increasing ester side chain length for linear alkyl (meth)acrylates may be explained by a decreasing concentration of the polar ester moieties, resulting in a decreasing stabilization of the attacking radical in the transition state of the propagation reaction, and (ii) the family type behavior of the branched alkyl methacrylates can be understood by considering steric and entropic influences. For the branched alkyl acrylates, no clear trend is detectable, and a family type behavior is clearly not observed in contrast to the corresponding methacrylates.

The radical propagation rate coefficients, k p , of methyl acrylate (MA) and 2-ethylhexyl acrylate (EHA) have been determined in bulk via high frequency (500 Hz) pulsed laser polymerization coupled to size exclusion chromatography (PLP-SEC) up to elevated temperatures (20 e T/°C e 80). Prior to the analysis of the generated polymeric material, an investigation into the branching behavior of the generated polymers has been undertaken, employing the concept of local dispersity, D(V e ). In addition, the Mark-Houwkink-Kuhn-Sakurada parameters for both poly(MA) and polyEHA were determined at each studied reaction temperature. The temperature averaged values read (K = 10.2 Â 10 -5 dL g -1 ; R = 0.741) and (K=9.85 Â 10 -5 dL g -1 ; R = 0.719) for poly(MA) and polyEHA, respectively. The local dispersity data indicate that branching in polyEHA may be considerably more prevalent than in poly(MA), as with increasing temperature polymer microinhomogeneities are observed. Consequently, the Arrhenius parameters for k p of EHA are beset with a larger error than those of MA. The activation parameters in the temperature range between 20 and 80 °Cread:E A MA = 18.5 (þ0.8 to -0.9) kJ 3 mol -1 and A MA =2.5 (þ1.2 to -0.6) Â 10 7 L 3 mol -1 3 s -1 ; E A EHA =15.8 (þ1.6 to -1.4) kJ 3 mol -1 and A EHA =9.1 (þ10.1 to -2.9) Â 10 6 L 3 mol -1 3 s -1 .

Propagation rate coefficients are provided—for the first time—for an entire class of urethane moieties containing acrylates, which display an extremely high propagation rate.