Cationic polymerization of dienes VII. New electron donors in the polymerization of 1,3-pentadiene initiated by aluminum trichloride in non-polar solvent

The aim of this research was to investigate new bulky electron donors (EDs) generating hindered active species in the cationic polymerization of 1,3-pentadiene initiated by AlCl3 in pentane, in order to avoid or strongly reduce the reaction between the active species and the double bonds of the polymer which are responsible for side reactions. At room temperature, the polymerization in the presence of new ED, such as OPh2, N(PhBr)3, NPh3 and SPh2, allowed to obtain higher conversions and lower insoluble fractions than without electron donor. The formation of a complex ED/AlCl3 was shown for each electron donor. However, in the case of NPh3 and SPh2, variations of the polymer microstructure demonstrated an interaction between active species and these EDs. Similar results were obtained at lower temperature (−10 °C). The beneficial effect of the presence of electron donors such as NPh3 and SPh2 demonstrated the validity of the concept of sterically hindered active species, but the polymerization was still uncontrolled.