Supplementary Figures from Chemoselective Lewis pair polymerization of renewable multivinyl-functionalized <i>γ</i>-butyrolactones

2017-06-16T14:35:53Z (GMT) by Ravikumar R. Gowda Eugene Y.-X. Chen
Multivinyl-functionalized <i>γ</i>-butyrolactones, <i>γ</i>-vinyl<i>-γ</i>-methyl-<i>α</i>-methylene-<i>γ</i>-butyrolactone (<i><sub>γ</sub></i>VMMBL) and <i>γ</i>-allyl-<i>γ</i>-methyl-<i>α</i>-methylene-<i>γ</i>-butyrolactone (<i><sub>γ</sub></i>AMMBL), have been synthesized from biorenewable ethyl levulinate and effectively polymerized by Lewis pairs consisting of an organic <i>N</i>-heterocyclic carbene Lewis base and a strong organo-Lewis acid E(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub> (E = Al, B). This Lewis pair polymerization is quantitatively chemoselective, proceeds exclusively via polyaddition across the conjugated <i>α</i>-methylene double bond without participation of the <i>γ</i>-vinyl or <i>γ</i>-allyl double bond, and produces high molecular weight functionalized polymers with unimodal molecular weight distributions. The Al-based Lewis pair produces the polymer with approximately 5.5 times higher molecular weight than that by the B-based Lewis pair. The resulting vinyl-functionalized polymers are soluble in common organic solvents and stable at room temperature, and can be thermally cured into crosslinked materials.