Cobalt Complexes Bearing Midified CNTs Grafted Novel Schiff Base Ligands:Synthesis,Structures And Catalytic Behavior For PS Polymerization

The preparation of novel polymeric materials using the after transition-metal catalyst is a very important research subject in the field of polymer chemistry.If can realize the "living"/controlled polymerization,the polymer with narrow molecular weight(MW)distribution and clear structure can be prepared.Moreover,the structure and properties of the prepared polymer will be distinct different if the catalyst has the nano structure.In the present study,the kind of catalysts have increased gradually,the research of which have also gradually deepened.Based on the above ideology,referring to a number of literatures,the Schiff base catalyst with good catalytic activity chosed,the unique structure of multi-walled carbon nanotubes have choosed to support nano materials and the monomer of polymerization is selected styrene with the vinyl structure.So the design philosophy of the paper is to discussed the Styrene polymerization with CMRP.Through the new method,new ligands—p-aminophenol shrinkage acenaphthene quinone Schiff bases,as shown in figure A,were synthesized,and characterized by means of IR,elemental analysis etc..Then the prepared shrinkage acenaphthene quinone Schiff base p-aminophenol cobalt(?)has been grafted with modified carbon nanotube surface,to synthetize the new catalysts with nano structure,as shown in figure B.Based on free radical polymerization mechanism with the media of Cobalt compounds,the complexes of newly synthesised choosed as catalyst,toluene as solvent,AIBN as initiator,for solution polymerization of styrene,to explore free radical polymerization of styrene controlled/"activce" properties and the polymerization behavior in different conditions.The new composition of modified carbon nanotubes grafted p-aminophenol shrinkage acenaphthene quinone Schiff base cobalt(?)choosed as catalyst,toluene as solvent,AIBN as initiator,to study free radical polymerization of styrene with CMRP.According to the analysis of the GPC data of polystyrene,except the control group,MW distribution of the prepared styrene polymer is mainly below 1.5,it is showed that the catalysts have noticeable catalytic activity and controllability to polymerization of styrene,which is to say experiment has achieved the "living"/controlled polymerization.When the reaction temperature increased,the polymer yield increasing significantly,the number average MW raising obviously,and the molecular weight distribution becoming wider,the reaction trend not controllable.But when the temperature kept same,the longer the reaction time,the higher the polymer yield,the bigger the number average molecular weight,the narrower the molecular weight distribution,and the reaction changed to a controlled direction.When other conditions being equal,increasing the amount of catalyst,the conversion rate firstly increasng and then decreasing,the MW distribution gradually decreasing,the MW did not change significantly,it is indicated that this kind of catalyst have significant agglomeration effect,and catalytic effect is the most obvious only in a certain proportion.The solubility of catalyst still remained to be improved;in four different catalyzed styrene polymerization by after transition-metal,the activityof nickel was the highest,and the largest molecular weight obtained by the catalyzed polymer,but with wide molecular weight distribution.The catalytic activity of cobalt is similar to iron,which the copper is worst.