Copolymerization of Ethylene and 4-Penten-1-ol Using an Aryl Sulfonate Phosphine Palladium Catalyst

Our goal was to investigate the copolymerization of ethylene with 4-penten-1-ol using an aryl sulfonate phosphine catalyst. In addition to several polymerizations of ethylene, used as control runs, more than a dozen copolymerizations were conducted at reasonable yields. As a main variable in these runs, we changed the comonomer concentration (ca. 0.10 to 2.82 mol/L). However, also the influence of polymerization time (1 h versus 21 hours runs), temperature (80 versus 95 oC), and catalyst concentration (160 μmol/L versus 820 μmol/L) was determined. Activities for all the runs were determined. For the first time, the 13C NMR spectra of the copolymers were analyzed and all peak assignments made. In addition, 1H NMR spectra were completely analyzed. Based on these spectra, the comonomer contents in the copolymers could be determined. The reactivity ratios for ethylene and 4-penten-1-ol were determined using the methods of Fineman-Ross and Kelen-Tüdŏs. Molecular weight properties measured by GPC are reported, as well as DSC-based melting temperatures. Some TGA measurements were conducted to determine the heat stability and purities of the copolymers. Finally the nature of the mechanism of the polymerization, coordinative as expected or radical, has been also discussed