No Apparent Correlation of k sub(p) with Steric Hindrance for Branched Acrylates

• Published in: Macromolecular chemistry and physics Vol. 216; no. 14; pp. 1573 - 1582
• Main Authors: Kockler, Katrin B, Haehnel, Alexander P, Fleischhaker, Friederike, Schneider-Baumann, Maria, Misske, Andrea M, Barner-Kowollik, Christopher
• Format: Journal Article
• Language: English
• Published: 01.07.2015
• Subjects: Acrylates; Branched; Chromatography; Coefficients; Esters; Monomers; Pulsed lasers; Trends
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.201500140

The Arrhenius parameters of the propagation rate coefficient, k sub(p), are determined via the pulsed laser polymerization-size exclusion chromatography (PLP-SEC) method for five branched acrylates (tert-butyl (tBA), isobornyl (iBoA), benzyl (BnA), 2-ethylhexyl (EHA), and 2-propylheptyl acrylate (PHA)) in 1 m solution in butyl acetate (BuAc) to complete the series, published by Haehnel et al. in 2014, of branched acrylates (isononyl (INA-A), tridecyl (TDA-A and TDN-A), heptadecyl (C17A), and henicosyl acrylate (C21A)) in solution that do not show a trend in k sub(p). Furthermore, the propagation rate coefficients of the branched acrylates in 1 m solution are critically compared with the branched acrylates in bulk as well as branched methacrylates. A summary of the trends and family-type behavior for the linear and branched (meth)acrylates as well as methacrylates with cyclic ester side chains is provided. For the branched acrylates in 1 m solution, no clear trends of the propagation rate coefficients, k sub(p), or Arrhenius parameters A and E sub(A) are detectable and-in contrast to the corresponding methacrylates-there is no family-type behavior observed in solution as well as in bulk. A series of branched acrylates in solution is investigated for trends and family-type behavior of their propagation rate coefficients and Arrhenius parameters. The data in solution are compared to previously published data of branched acrylates in bulk and branched methacrylates accompanied by an encompassing synopsis of the so-far reported trends among acrylic and methacrylic monomers.