Synthesis of novel reactive polymers by allylboration polymerization

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Novel boron-containing polymers were obtained by polyaddition between dicyano compounds and allylboranes such as triallylborane, trimethallylborane, and allyldialkylboranes.When polymerization between triallylborane and isophthalonitrile was carried out in bulk at 0ﾟC,the reaction mixture became homogeneous liquid within several minutes. After the reaction for 1 day, a glassy polymer was obtained. The molecular weight of the resulting polymer was estimated by GPC,from which M_n and M_w were found to be 14,000 and 25,700, respectively. The structure of the polymer was confirmed by ^1H-, ^<11>B-NMR,and IR analyzes. The air- as well as thermal stabilities of the obtained polymers were examined. Most part of the resulting boron-containing polymers became insoluble upon the storage even under the inert atmosphere. By heating the polymer around 140ﾟC,an irreversible chemical reaction (i.e., further allylboration reaction) took place and the polymer became insoluble accompanying its structura … More l change. Similarly to the polymers prepared by hydroboration polymerization of dicyano monomers, these polymers gave some residue after pyrolysis.Allylboration polymerization was also examined with trimethallylborane. When polymerizations of alpha, omega-dicyanoalkanes were carried out in bulk at ambient temperature, the allylboration reactions were completed instantly, but the molecular weights of the resulting polymers increased very slowly. The siow rate of polymerization in comparison with that of triallylborane was responsible for the slow dimerization of sterically hindered iminoboranes. In the case of aromatic dicyano monomers such as isophthalonitrile, the reaction with triallyborane produced oligomers as a results of the insufficient dimerization that could be clearly followed by its IR measurement. The structures of the obtained polymers were confirmed by their spectroscopic measurements. The boron-containing polymers from trimethallylborane were found to be somewhat stable in comparison with those obtained from triallylborane. Less