Effect of lithium chloride on the living polymerization of tert-butyl methacrylate and polymer microstructure using monofunctional initiators
- Rt Polymer Source Inc., Pointe-Claire, Quebec (Canada)
- Imperial Oil Ltd., Sarnia, Ontario (Canada). Research Dept.
- McGill Univ., Montreal, Quebec (Canada). Dept. of Chemistry
The effect of LiCl on the anionic polymerization of tert-butyl methacrylate (tBuMA) initiated with monofunctional alkali metal-based carbanionic species was investigated at [minus]78 C in THF. The propagation rate of the polymerization process was determined by gas chromatography and by gravimetry. It was found that, in the presence of LiCl in a molar ratio of 5 with respect to the initiator, the rate constant, k[sub p], is 20 times lower than that in the absence of LiCl. The polymers and oligomers were analyzed by size exclusion chromatography (SEC) and [sup 13]C NMR spectroscopy. The polymers obtained in the absence of LiCl had broad molecular weight distributions and contained significant amounts of oligomers, while those obtained in the presence of LiCl were monodisperse, without any noticeable oligomers. [sup 13]C NMR showed that the isotactic content of the polymers increased significantly when the molar ratio of LiCl to the initiator was higher than 2. The effect of LiCl on the rate constant and on the microstructure of the polymers was attributed to complex formation between LiCl and the living polymer chains.
- OSTI ID:
- 7288128
- Journal Information:
- Macromolecules; (United States), Journal Name: Macromolecules; (United States) Vol. 27:5; ISSN MAMOBX; ISSN 0024-9297
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360602 -- Other Materials-- Structure & Phase Studies
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ACRYLATES
ALKALI METAL COMPOUNDS
CARBOXYLIC ACID SALTS
CATALYTIC EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
ESTERS
FURANS
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
KINETICS
LITHIUM CHLORIDES
LITHIUM COMPOUNDS
LITHIUM HALIDES
MICROSTRUCTURE
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANIC POLYMERS
POLYACRYLATES
POLYMERIZATION
POLYMERS
POLYVINYLS
REACTION KINETICS
TETRAHYDROFURAN