Abstract
AbstractThe radical copolymerization of methyl methacrylate (MMA) and styrene (St) in the presence of various metal halides was conducted to achieve the advanced regulation of comonomer‐sequence and stereosequence in the resulting copolymers. The alternation‐regulating activities of various metal halides were determined quantitatively by the MMA content in the copolymer prepared under the specific conditions. Boron trichloride, aluminum tribromide and ethyl boron dichloride were found to have large alternation‐regulating activities, yielding the strictly alternating MMA‐St copolymers with high regulation of comonomer‐sequence. The cotacticities of the ‐MMA‐St‐ diad, the ‐St‐MMA‐St‐ triad and the‐MMA‐St‐MMA‐ triad in the alternating copolymer were determined by 1H‐ and 13C‐NMR spectroscopies. The cotacticities depend on the species and the concentrations of the metal halides, and on the polymerization temperatures. The alternating MMA‐St copolymer with the highest coheterotacticity has been prepared by using boron trichloride at − 95 °C. The mechanism of the stereosequence regulation is described in detail. Copyright © 2003 John Wiley & Sons, Ltd.
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