Preparation And Laboratory Technology Research Of The Catalyst For The Hydrogenation Of Styrene-butadiene-styrene Block Copolymers

The titanocene dichloride catalyzed hydrogenation of SBS was systematicallystudied in this thesis. The techniques for the preparation of titanocene dichloridewere well mastered. And titanocene dichloride catalyst was bulk produced. Thehydrogenation expreiment of finished produced of SBS was carried out in a limmitedcondition, such as far away from the main market and restricted by traffic factors.The conditions for the activation treatment of the finished produced of SBS was wellinvestigated. And n-BuLi was added as an initiator in the hydrogenation process. Inoptimum conditions, a similar degree of hydrogenation was obtained according withthat of the fresh SBS system. The thesis mainly consists of the five chapters asfollows:Chapter one: ReviewsThis chapter mainly reviewed the following six subsections including:(1) Thestructural characteristics of the polystyrene-polyethene-polybutadiene-polystyrene(SEBS). The excellent property of SEBS refering to SBS which was abtained bythroughtly hydrogenantion of the unsaturated double bond exsited in the molecularchain of SEBS was introduced.(2) The research significance and the application ofSEBS. The abvious advantages of SEBS, including the weather ability, the heatresistance, the compression resistance, the excellent mechanical properties as well asthe large potential application, were mainly introduced.(3) The synthesis technologiesof SBS technologies. The commonly used synthesis technologies of SBS weresummarized, and the advantage as well as disadvantages of each technology wasdissected.(4) The hydrogenation technology of SBS hydrogenation technology. Thetwo hydrogenantion methods of SBS were concluded, and the application ofmetallocene in the hydrogenation was chiefly introduced.(5) The hydrogenationmechanism of SBS. The the π-complex concerning mechanism as well as the cationicactive centers mechanism was introduced.(6) The research status of SEBS. Thedomestic and foreign research advancement of SBS was introduces, the existingproblems of SEBS research was pointed out.Chapter two: The preparation and catalytic properties of the titanocenedichloride Firstly, through a continuous twice distillation technology, the titanocenedichloride catalyst with high purity was synthesized, and its structures wascharacterized by1H-NMR spectroscopy. Secondly, the catalytic hydrogenationproperty of the synthesized catalyst was investigated through the hydrogenation of thefinished produced SBS rubber and the fresh SBS rubber. The hygrogenation resultsobtained by the synthesized catalyst and the industrial catalyst was compared. It wasfound that under the same experimental conditions, the homemade catalystperformanced better than that of the industrial catalyst; It also showed that thehydrogenation activity of the finished produced SBS rubber was low and it must beactivated before the experiment in order to improve its hydrogenation degree.Chapter three: The preparation and pretreatment research of SBSFirstly, the preparation conditions of SBS was studied, the various influencefactors on the preparation of raw SBS rubber was investigated. Secondly, theinfluence of water exsited in the solvents, the rubber’s wash methods as well as thedrying methods procedures on the hydrogenation of SBS was studied. The resultsshow that the water in the solvent, the additives and the preservatives in SBS rubber,and the drying procedures all have an effect on the improvement of the hydrogenationdegree of SBS rubber. To improve the hydrogenation degree of SBS rubber, it wasneccesary to pretreat the the finished product SBS rubber through solvent bidistrilling,impurity washing as well as vacuum drying of SBS rubber.Chapter four: Optimization of the hydrogenation conditions of SBS and thedetermination of laboratory test technologiesHigh actived SBS was prepared with the catalysis of titanocene dichloride beforethe pretrentment of SBS rubber through solvent bidistrilling, impurity washing andvacuum drying. The unactivated hydrogenation process of SBS rubber was firstlyinvestigated, the result show that only a hydrogenation degree of25.0%was obtainedin a unactivated hydrogenation process. Then, the hydrogenation conditions of SBSwere optimized, and the influence of H2pressure both in reaction and in activationprocess, the dosage of n-BuLi, the activation time, as well as the dosage of of the,were furtherly invesigated. It was show that the two main factorsactivationpretreatment and the dosage of the catalyst, had a obvious effect on the hydrogenation degree, and the pretreatment process played an important role in the hydrogenation. Itwas found that the optimum conditions for the hydrogenation of SBS are: the H2pressure for the activation process is1.5MPa, the activation time is3h, the H2pressurefor the reaction process is2.5MPa, the dosage of n-BuLi is3mL, and the amount ofcatalyst is20mL. Under this condition, the hydrogenation degree SEBS reached92.0%.Chapter five: The comparison of the catalytic hydrogenation performancebetween the homemade catalyst and the industrial catalystThe catalytic performance of the industrial catalysis from YueyangPetrochemical and the homemade catalyst for the hydrogenation of SBS wascompared under three unique conditions, including the same optimum conditions,the unactivation process, and the halving of the amount of catalyst, respectively. Theresults indicated once again that the activation process is still the key factorsinfluencing the hydrogenation degree of SBS. Under the same reaction conditions,the hydrogenation degree of85.0%was obtained by the industrial catalyst, whereas,92.0%for homemade catalyst. It suggested that the catalytic performance of thehomemade catalyst was better than that of the industrial one. The result will lay thefoundation for future industrial applications of the synthesized titanocene dichloridecatalyst.