Synthesis of Well-Defined Novel Reactive Block Polymers
Containing a Poly(1,4-divinylbenzene) Segment by Living Anionic Polymerization
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Abstract
In
order to synthesize a variety of block polymers having poly(1,4-divinylbenzene)
(PDVB) segments, the living anionic block polymerizations of DVB with
styrene, 2-vinylpyridine (2VP), <i>tert</i>-butyl methacrylate
(<sup>t</sup>BMA), methyl methacrylate (MMA), <i>N</i>-(4-vinylbenzylidene)cyclohexylamine
(<b>1</b>), 2-(4′-vinylphenyl)-4,4-dimethyl-2-oxazoline
(<b>2</b>), or 2,6-di-<i>tert</i>-butyl-4-methylphenyl
4-vinylbenzoate (<b>3</b>) were conducted in THF at −78
°C with the anionic initiator bearing K<sup>+</sup> in the presence
of a 10-fold excess of potassium <i>tert</i>-butoxide. With
the sequential addition of DVB and each of these monomers, the following
block polymers having PDVB segments were successfully synthesized:
PS-<i>b</i>-PDVB, P2VP-<i>b</i>-PDVB, PDVB-<i>b</i>-P2VP, PDVB-<i>b</i>-P<sup>t</sup>BMA, PDVB-<i>b</i>-P(<b>1</b>), PDVB-<i>b</i>-P(<b>2</b>), PDVB-<i>b</i>-P(<b>3</b>), PS-<i>b</i>-PDVB-<i>b</i>-P<sup>t</sup>BMA, PS-<i>b</i>-P2VP-<i>b</i>-PDVB-<i>b</i>-P<sup>t</sup>BMA, and PS-<i>b</i>-PDVB-<i>b</i>-P2VP-<i>b</i>-P<sup>t</sup>BMA. The resulting polymers are all novel block polymers with
well-defined structures (predictable molecular weights and compositions
and narrow molecular weight distributions) and possess reactive PDVB
segments capable of undergoing several postreactions. Based on the
results of such sequential block polymerizations, the anionic random
copolymerization of DVB and 2VP, the polymerizability with (C<sub>4</sub>H<sub>9</sub>)<sub>2</sub>Mg, and some other addition reactions,
it was found that the comparable reactivity of the chain-end anions
follows the sequence of PS<sup>–</sup> > PDVB<sup>–</sup> > P2VP<sup>–</sup> > P<sup>t</sup>BMA<sup>–</sup>.
Accordingly, the reactivity of the corresponding monomers increases
as follows: styrene < DVB < 2VP < <sup>t</sup>BMA
