Studies On The Mothodology Of Living Anionic Polymerization Using High Vacuum Technique

Living anionic polymerization is the most effective method to synthesize polymers with molecular weight, structure and molecular weight distribution under control. In recently years, the living anionic polymerization method is widely used for the synthesis of a series of novel polymers with complicated structures and broad application prospects. The corresponding experiments are strictly demanded free of oxygen and moisture for the high activity of carbanions. High vacuum technique, could make the reaction system closed and remove the impurities completely, is the essential experimental technique for the theoretical methodologic studies on living anionic polymerization. In this thesis, self designed high vacuum technique was constructed and corresponding anionic methodological researches were carried out.First, the self designed high vacuum technique was developed and constructed. Based on the long term practice, some key operation methods and apparatuses using in the operation of high vacuum technique were modified to make the reaction experiments safe and easy. A novel method that complicated apparatuses could be constructed by glass blowing of separated units of the apparatuses was developed and widely applied in living anionic polymerization reaction. The purification of agents with low boiling-point used for reactions, such as butadiene and epoxyethane, under high vacuum conditions was modified, which was more convenient and effective. The purification of agents with high boiling-point, such as 4-vinylphenyldimethylsilane (VPDMS) and the derivatives of DPE, was developed. The synthetic operation and apparatuses were modified, which made the reaction safe and effective. The apparatuses of synthesis of dilithium initiator and copolymers were modified and developed. A novel apparatus for quantified iterative titration reaction was developed. Based on theses modifications and design, anionic methodological researches were carried out.Second, the synthetic method of hydro-carbon soluble dilithium initiator was modified based on the self designed high vacuum technique. The dilithium initiator was synthesized by one step with the 0.5% excess of sec-BuLi, which made the reaction more facilitated and best use of MPEB. The functionality of dilithium initiator synthesized was 1.98. The polybutadienes with molecular weight and microstructure under control were obtained while the synthesized dilithium as initiator. Furthermore, the methodology of synthesis of hydro-carbon soluble dilithium initiator was constructed based on the self designed high vacuum technique.Third, the novel quantified iterative titration apparatus was used for synthesis of cyclic polybutadienes. The cyclic coupling reaction was done with synchronous titration under high dilution situations with synthesized dilithium initiator and MPEB and BDMCSE as coupling agents. The mechanism of cyclic reactions was investigated and the cyclic polybutadienes were obtained with BDMCSE as coupling agent. The methodology of synthesis of cyclic polymers was constructed based on the self designed high vacuum technique. Furthermore, the synthetic method is the base of studies on polymers with complicated topological structure.At the end, based on the self designed high vacuum technique, a novel functionalized thermoplastic elastomer F-SBS (PVPDMS-b-PBd-b-PVPDMS) copolymers were synthesized with the synthesized dilithium initiator at first time. After the living polybutadienes were obtained, the copolymerization was done in the apparatus for the synthesis of copolymers. A novel functionalized thermoplastic elastomer F-SBS with silyl-hydride groups was synthesized. The F-SBS block copolymers were characterized by1H-NMR, GPC and DSC and the structures were confirmed. The results showed that Mn was 88 kg/mol, Mw/Mn was 1.10, the glass transition temperatures were-86℃and 85℃, respectively. The silyl-hydride groups in polymers could prepare novel functionalized polymers by hydrosilylation reactions. Furthermore, the method of synthesis of multi-block copolymers was constructed base on the self designed high vacuum technique.