Synthesis and Hydrogenation of 1,2-1,4-1,2-Stereotriblock Polybutadienes and the Study of Their Properties |
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Authors: | Hongquan Xie Liren Ma |
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Affiliation: | Hubei Research Institute of Chemistry , Wuhan, People' Republic of China |
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Abstract: | The effects of various polar modifiers, their concentration, and the polymerization temperature on the microstructure of poly-butadiene obtained during anionic polymerization using lithium α-methyl naphthalene as the bifunctional initiator were studied. 1,2-1,4-1,2-Stereotriblock polybutadiene was synthesized by polymerization in cyclohexane to a certain conversion and polymerization was completed in the presence of diethylene glycol dimethyl ether. The microstructure of the stereotriblock copolymer was characterized by IR and 1H-NMR. GPC showed that the stereo-block polybutadiene has a narrow MWD. Two Tg's of the copolymer with higher molecular weight exist, as shown by dynamic mechanical test. The stereotriblock copolymer was hydrogenated using cobalt 2-ethyl hexanoate and triisobutyl aluminum as the catalyst. The hydrogenated product was shown to be a (butene-1-ethylene-butene-1) triblock copolymer which consists of more than 30% crystallinity and exhibits the behavior of a thermoplastic elastomer. The relationship between stress-strain properties arid the contents of the blocks was also studied. |
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