Global Trends for k p? Expanding the Frontier of Ester Side Chain Topography in Acrylates and Methacrylates

• Published in: Macromolecules 2013-01, Vol.46 (1), p.15-28
• Main Authors: Haehnel, Alexander P, Schneider-Baumann, Maria, Hiltebrandt, Kai U, Misske, Andrea M, Barner-Kowollik, Christopher
• Format: Article
• Language: English
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma302319z

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).