| In the field of polymer materials,poly-1-butene is known as 'Plastic Gold' for its excellent physical properties.However,due to the failure to develop qualified polymerization catalyst that meets industrial requirements,China hasn't been fully achieve independent industrial production of poly-1-butene.At present,during the preparation of Ziegler-Natta catalyst,MgCl2,Mg?OEt?2,and grignard reagent,which are sensitive to water and oxygen,are mainly used as magnesium source.This leads to several problems,such as high cost and complex process,making it difficult for industrialization.Aiming at this problem,a new type of Ziegler-Natta catalyst was successfully prepared with water-soluble magnesium acetate as its megnesium source and Si/Mg as its carrier.In this paper,the effects of various variables on 1-butene polymerization were investigated,including megnisium dosage,reaction temperature,co-catalyst dosage,type and amount of internal-and external eletron donor and also hydrogen addtion.From the experimental data,when magnesium content is 15wt%,Al/Ti molar ratio is 30 and reaction temperature is 30?,the catalyst exhibits its optimal performance,i.e.76.9 gPB?gcat?-1 h-1,with 9,9-bis?methoxymethyl?fluorene?BMMF?as its internal electron donor and three isobutyl aluminum as co-catalyst.However,with triethylaluminium?TEA?as co-catalyst,it showed poor activity,only 30.1 gPB?gcat?-1 h-1.When dicyclopentyldimethoxysilane?D-donor?was used as external electron donor and Si/Ti molar ratio was 4,the isotactic index of polymerizaion products reached its maximum value 97.8%.Meanwhile,this new catalyst shows good hydrogen transfer performance,which can reduce the molecular weight of the polymer significantly.Keeping megnisium content is 15wt%and using internal electron donor as variables,catalyst system with diisobutyl phthalate?DIBP?as internal electron donor,and catalyst system without internal electron donor both showed lower polymerization activity and isotacticy index than BMMF system. |
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