頁籤選單縮合
題名 | Synthesis of Poly (2,3-Dimethyl-1,3-Butadiene) and its Hydrogenation Using a Metallocene/N-Butyllithium Catalyst System= |
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作者 | Chiang,Won-li; Hsieh,Henry Chi-chen; Tsiang,Raymond Chien-chao; |
期刊 | Journal of Polymer Research |
出版日期 | 19981000 |
卷期 | 5:4 1998.10[民87.10] |
頁次 | 頁227-232 |
分類號 | 346.84 |
語文 | eng |
關鍵詞 | Anionic; Polymerization; Hydrogenation; Head-to-head; 2,3-dimethyl-1; 3-butadiene; Polypropylene; |
英文摘要 | Poly(2,3-Dimethyl-1,3-butadiene) (PDMB) with varying contents of 1,4- and 1,2-structures has been anionically synthesized using either n-butyllithium or sec-butyllithium as an initiator. The addition of tetrahydrofuran could enhance the rate of synthesis and effect the microstructure. The T�o was higher for PDMB with a lower content of 1,2-structure, and the Tg was lower. This PDMB was then hydrogenated with a nickelocene/n-butyllithium catalyst system leading to the formation of HPDMB. The trans 1,4-structure unit was more difficult to hydrogenate due to its steric hindrance. Repetitive hydrogenation was necessary in order to achieve a high degree of hydrogenation. The hydrogenated PDMB is an amorphous elastomeric material. The Tg's were found to decrease with an iccrease in the degree of hydrogenation, concurrent with a gradual disappearance of the T�o's. Since a HPDMS with a low content of 1,2-structure resembles a head-to- head polypropylene, our data suggest that the Tg of an atactic head-to-head polypropylene lie between-30 and-35℃. |
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