Anionic polymerization of MMA and renewable methylene butyrolactones by resorbable potassium salts

Abstract

Three resorbable potassium salts of hydride (K[H]), enolate Me2CC(OiPr)OK (K[E]), and allyl K[1,3‐(SiMe3)2C3H3] (K[A]) have been investigated for controlled anionic polymerization of methyl methacrylate (MMA) and its cyclic analogs, naturally renewable methylene butyrolactones including α‐methylene‐γ‐butyrolactone (MBL) and γ‐methyl‐α‐methylene‐γ‐butyrolactone (MMBL). When used alone at ambient temperature in toluene, these salts exhibit no (K[H]) to low (K[A]) to modest (K[E]) polymerization activity. Mixing of K[H] and Al(C6F5)3 leads to the formation of an “ate” complex, K+[HAl(C6F5)3]−, which has been structurally characterized by X‐ray diffraction; this complex has a high polymerization activity producing atactic PMMA, but addition of another equiv of Al(C6F5)3 further enhances both the rate and the efficiency of the polymerization, now producing syndiotactic PMMA with a narrow molecular weight (MW) distribution of 1.04. The K[H]/2Al(C6F5)3 system also exhibits high activity for polymerization of (M)MBL. In sharp contrast, addition of Al(C6F5)3 to K[A] shuts down the polymerization at various temperatures. The most active, controlled, and syndioselective polymerization system in this series is K[E]/2Al(C6F5)3. Accordingly, the polymerization control and kinetics of this most effective system have been examined in more detail. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Polymerizability of Exo‐methylene‐lactide toward vinyl addition and ring opening

“…In this context, the parent α ‐methylene‐ γ ‐butyrolactone (MBL), which is found naturally in tulips or produced chemically from biomass feedstocks and represents the simplest member of the naturally occurring sesquiterpene lactone family, has been a subject of intensive investigation. MBL has been polymerized using many different polymerization methods, including free radical, atom‐transfer radical, anionic, zwitterionic, group‐transfer, and coordination polymerization . These processes, regardless of the polymerization mechanism or method, produce exclusively a vinyl‐addition polymer, PMBL (Scheme ), proceeding through conjugate addition across the exo ‐methylene CC double bond without ring‐opening of the five‐membered γ ‐butyrolactone ( γ ‐BL) ring.…”

Functional Polymers and Polymeric Materials From Renewable Alpha-Unsaturated Gamma-Butyrolactones

“…The most studies of MBL derivatives describe their polymerization exclusively via vinyl addition of exo-methylene double bond without ring opening of lactone ring using various polymerization techniques, including free radical (Akkapeddi, 1979a), reversible deactivation (Mosnácek and Matyjaszewski, 2008), coordination (Miyake et al, 2010a), group transfer (Miyake et al, 2010b), or anionic polymerization (Hu et al, 2011; Figure 1).…”

α‐exomethylene lactone possessing acetal–ester linkage: Polymerization and postpolymerization modification for water‐soluble polymer

“…α‐Exomethylene lactones (EMLs) are cyclic acrylates, which afford vinyl polymers via radical, anionic, and coordination polymerization as an acrylate monomer as well as polyesters via ring‐opening polymerization (ROP) . In particular, EMLs with 5‐membered ring such as α‐methylene‐γ‐butyrolactone (MBL), α‐methylene‐β‐methyl‐γ‐butyrolactone (βMMBL), and α‐methylene‐γ‐methyl‐γ‐butyrolactone (γMMBL) are known as renewable monomers from biomass products. Moreover, since their vinyl polymers exhibit higher glass transition temperatures ( T g s) than a typical acrylic polymer, poly(methyl methacrylate) (PMMA), the polymerization of EMLs has gained much attention.…”