Cotelomers of 4-vinylpyridine (VP) and methyl acrylate (MA) prepared in a telogen of 1-dodecanethiol (LSH) or 1-dodecanol (LOH) were characterized. Ls-VP-MA accounting for 6.110.9 of the degree of polymerization (
Pn) was a brown viscous liquid. The ratio of LSH to monomers (VP+MA) in the feed (β) was proportional to 1/
Pn. A plot of MA to VP (α)
vs. the chain-transfer constant (
Cs) gave a straight line from which the following formula (1) was derived.
1/
Pn= {4.6×10
-1/ (1+α) +8.4×10
-2} β+2.5α×10
-3+7.6×10
-2 (1)
The monomer composition of Ls-VP-MA was not effected by β, and the reactivity ratios of
rVP and
rMA calculated using the Fineman-Ross equations were 1.9 and 0.25, respectively. Lo-VP-MA prepared at 70°C was a yellow precipitate and 85211 of
Pn, and that prepared at 175°C was a brown precipitate and 1244 of
Pn. An approximately linear relationship was found between β and 1/
Pn and the following equation was consequently derived.
1/P
n= {5.3×10
-3/ (1+α) +7.8×10
-4} β+4.5α×10
-3-5.0×10
-3 (2)
The monomer-cotelomer composition curve for Lo-VP-MA was similar to that of Ls-VP-MA. The reactivity ratios of
rVP and
rMA were 2.1 and 0.23, respectively. The reciprocal of P
n of Ls-VP-St (styrene) and Lo-VP-VAc (vinyl acetate) increased with β, and their reactivity ratios were essentially the same as those for the copolymerization of VP-St or VP-VAc.
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