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以四氢呋喃为极性添加剂,工业二乙烯基苯(DVB)为偶联剂,用阴离子聚合方法合成了星型聚丁二烯。用气相色谱法测定了聚丁二烯鋰与工业DVB四种单体(p-DVB,m-DVB,m-EVB,p-EVB)的偶联共聚速率,同时测定了反应活化能。结果表明:工业DVB四种单体的反应速率都比在纯环己烷中快,其中p-DVB和m-DVB的反应速率增加尤为明显;反应活化能分别为29.3,30.1,43.5和44.5kJ/mol,均比在纯环己烷中有大幅度地下降。改变THF/Li配比,p-DVB和m-DVB的反应速率随THF/Li增加而提高,而m-EVB和p-EVB的反应速率随THF/Li增加均出现极值。少量THF可加速偶联速率,当THF/Li=6时,在2～3分钟内可使偶联效率提高到90%。
The star polybutadiene was synthesized by the anionic polymerization method using tetrahydrofuran as the polar additive and industrial divinylbenzene (DVB) as the coupling agent. The coupling copolymerization rate of polybutadiene lithium and industrial DVB four monomers (p-DVB, m-DVB, m-EVB and p-EVB) was measured by gas chromatography. The results show that the reaction rate of industrial DVB four monomers is faster than that of pure cyclohexane, and the reaction rate of p-DVB and m-DVB increases more obviously. The reaction activation energies are 29.3, 30.1, 43.5 and 44.5 kJ / mol, than in pure cyclohexane have dropped significantly. The reaction rate of p-DVB and m-DVB increased with the increase of THF / Li, while the reaction rate of m-EVB and p-EVB all increased with the increase of THF / Li. A small amount of THF accelerates the coupling rate. When THF / Li = 6, the coupling efficiency can be increased to 90% within 2 ~ 3 minutes.