6533b835fe1ef96bd129f3eb
RESEARCH PRODUCT
Anionic Polymerization of Alkyl (Meth)acrylates Using Metal-Free Initiators: Effect of Ion Pairing on Initiation Equilibria
Swaminathan SivaramDurairaj BaskaranAxel H. E. MüllerThieo E. Hogen-eschS. Chakrapanisubject
chemistry.chemical_classificationPolymers and PlasticsOrganic ChemistrySolution polymerizationPolymerInorganic Chemistrychemistry.chemical_compoundAnionic addition polymerizationchemistryPolymerizationPolymer chemistryMaterials ChemistryHofmann eliminationCounterionMethyl methacrylateAlkyldescription
Metal-free anionic polymerizations of alkyl (meth)acrylates using tetrabutylammonium salts of diethylphenylmalonate, fluorene, and 9-ethylfluorene as initiators were performed in THF at 30 °C. A poor control of molecular weights, inconsistent initiator efficiencies, and broad or bimodal molecular weight distributions were obtained. The effect of counterion nature was studied from the polymerization of methyl methacrylate using the 1,1-diphenylhexyl anion with tetrabutylammonium, tetramethyldiethylguanidinium, and lithium as counterions under otherwise identical conditions. Metal-free initiators resulted in incomplete initiation which is attributed to the fact that the initiation is an equilibrium reaction. In conjunction with possible side reactions such as Hofmann elimination and transfer reactions, this leads to broad and bimodal molecular weight distributions of the resulting polymers.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1999-04-15 | Macromolecules |