Study Of SSBR Initiated By Lithiumamide

In this paper, a new kind of lithiumamide initiator used to initiate copolymerization of Butadiene(Bd) and Styrene(St) is synthesized, and the process is monitored by means of gas chromatograph. The result of 13C-NMR shows that the amine is incorporated at the end of the polymer initiated by lithiumamide, which proves that N-Li is indeed the site of initiation.Considering the sensitivity of amine in anionic polymerization, the homopolymerization and copolymerization of Bd and St initiated by lithiohexamethyleneimine(LHMI) and lithiopyrrolidinide(LPY) are studied. Lithiumamide can initiate polymerization of Bd quickly, but can not initiate polymerization of St. After adding little Bd, St can be initiated by lithiumamide. When TMEDA/Li <2, the number of reactive species does not change obviously, and with the increase of TMEDA/Li, the homopolymerization rate of Bd increases; the homopolymerization rate of St increases and approaches maximum when TMEDA/Li is around 0.5 then decreases; the copolymerization rate of Bd and St increases and approaches maximum when TMEDA/Li is around 1.0 then decreases; with the increase of TMEDA the 1,2-content and the styrene content increase. When TMEDA/Li>2, with the increase of TMEDA/Li, the homopolymerization and copolymerization rate does not change obviously; the homopolymerization of Bd decreases in high temperature; with the increase of TMEDA the 1,2-content does not change obviously. With the increase of polymerization temperature, the polymerization rate increases; at high temperature and TMEDA/Li the polymerization rate decreases contrarily. With the increase of polymerization temperature, the 1,2-content decreases. The comparison between copolymer of Bd and St and homopolymer of Bd shows the introduction of St leads to decrease of 1,2-content in copolymer of Bd and St. The monomer reactivity ratios are calculated by KT mothed, and results show that with the increase of TMEDA/Li rad decreases and ra increases. The copolymer composition is simulated through copolymer composition equation and the copolymerization rate is calculated by Runge-Kutta method, lithiumamide has no obvious effect on polymerization rate, 1,2-contentand reactivity ratios.Hexamethyleneimine(HMI) has strong chain-transfer ability, and can be used to adjust molecular weight and molecular weight distribution, by using LHMI/HMI system, the amine is incorporated at the end of each polymer chain. But the polymer chain terminated by HMI has only one functional group.DMA result shows that in LHMI system the tan 8 value at O'C is similar to that in butyllithium system and the tan 5 value at 60 is smaller than that in butyllithium system, which means the butadiene-styrene rubber initiated by LHMI has lower hysteresis loss value.