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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 8, Number 2
February 20, 1987 

Syntheses of Alternating Head-to-Head Copolymers of Vinyl Ketones and Vinyl Ethers, and Their Properties. Ring-Opening Polymerization of 2,3,6-Trisubstituted-3,4-dihydro-2H-pyrans
Ju-Yeon Lee, Iwhan Cho
2-Methoxy-6-methyl-3,4-dihydro-2H-pyran (1a), 2-ethoxy-3,6-dimethyl-3,4-dihydro-2H-pyran (1b), and 2-ethoxy-3-methyl-6-ethyl-3,4-dihydro-2H-pyran (1c) were prepared by (4 + 2) cycloaddition reaction from the corresponding vinyl ketones and alkyl vinyl ethers. Compounds 1a-c were ring-open polymerized by cationic catalyst to obtain alternating head-to-head (H-H) copolymers. For comparison, copolymer of head-to-tail (H-T) was also prepared by free radical copolymerization of the mixture of the corresponding monomers. The H-H copolymer exhibited some differences in its 1H NMR and IR spectra. However, significant differences were showed between the H-H and H-T copolymers in the 13C NMR spectra. Also noteworthy was that Tg value of H-H copolymer was higher than that of the corresponding H-T structure. Decomposition temperature of the H-H copolymer was lower than that of the H-T copolymer. All the H-H and H-T copolymers were soluble in common solvents.
102 - 105
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