The Synthesis Of Block And Star Polymers Based On Trans-1,4-Polyisoprene

Trans-1,4-polyisoprene(TPI)has excellent performance of high hardness and high tensile strength,mainly used in medical functional materials and golf cladding layer.The sulfide products used as tire material,shows outstanding dynamic mechanical properties,which fits the development of the green tire requirements.It is difficult to process and blend with other rubbers since the crystallization of TPI at room temperature,which makes its industrial application be restricted in the tire industry.In this paper,TPI with stable Mooney viscosity and narrow molecular weight distribution was compounded by regulating and controlling the external electron donor in bulk polymerization.On this basis to end group functionalization,we obtained the single-ended telechelic TPI,and the block polymers and star polymers was prepared in the end.Firstly,on the basis of load titanium catalyst system,we chose different external electron donor to explore the relationship between the external electron donor and the morphology,Mooney viscosity,molecular weight,molecular weight distribution,productivity of TPI,the results show that choosing triethylamine as external electron donor we got the TPI with stable Mooney viscosity and narrow molecular weight distribution in bulk polymerization.The double carbonyl TPI(CTTPI)as an object of terminated-functionalized,the aldol condensation of ethylene glycol with terminal aldehyde of CTTPI generated shrinkage ether keys in the presence of p-toluene sulfonic acid,in this way,the protection of aldehyde was achieved,then the reduction hydroxylation with NaBH4 of ketone of subsequent product was achieved,the single-ended hydroxyl TPI(TPI-OH)was obtained in the end.Selective reductive amination of terminated aldehyde of CTTPI was achieved by the use of NaBH(OAc)3 and acetic acid,the single-ended amino TPI(TPI-NH2)was obtained in the presence of ammonium acetate in the end.The ATRP macromolecular initiators TPI-Br were successfully synthesized through the amidation reaction between single terminated-amino of TPI-NH2 and 2-bromoisobutyryl bromide.Then TPI-Br as initiator,reacting with styrene.A series of double block copolymers 1,4-polyisoprene-block-polystyrene(TPI-b-PS)were prepared.The TPI-Br as initiator,divinyl benzene(DVB)as crosslinking agent,TPI star polymer was prepared in “arm first”method.The naphthalene potassium as catalyst,three block polymers polyethylene oxide-block-1,4-polyisoprene-block-polyethylene oxide(PEO-b-TPI-b-PEO)were prepared by the reaction of HTTPI(HO-TPI-OH)and oxirane.