Transition Metal Catalyzed Copolymerization Of Propylene With Tertiary Amine Functionalized ?-olefin

As one of the most important polymers,isotactic polypropylene(i PP)has enjoyed wide application and commercial success owing to its combination of outstanding physical property,excellent chemical resistance,light weight,recyclable and especially cost-effective.Nevertheless,the lack of functionality leading to low surface properties,adhesion,and compatibility with other polymers,severely limits some high value end use of i PP materials.Therefore,introducing polar functionality into the polyolefin backbone to match the desired material properties for high-value specialty applications has attracted increasing interest.1.The stereoselective coordination copolymerizations of propylene with amino olefins bearing different protecting substituents by use of the dimethyl(pyridlamido)Hf catalyst system were described.Two methyl or ethyl groups were too small to protect the oxophilic catalytic center from getting deactivated by the tertiary amine,while two bulkier isopropyl or phenyl groups around the nitrogen played important role in both high copolymerization activity and producing high-molecular-weight,structure-controllable copolymers with high polar comonomer incorporation.Copolymerization of propylene and polar monomer yielded high tactic PP copolymer with molecular weight of 68.8×10⁵and polar comonomer incorporation up to 7.8 mol%and tacticity([mmmm]>99%).In addition,the homopolymerization of amine-based polar monomers was also studied,P[5-(N,N-diisopropyl amino)-1-pentene]and P[5-(N,N-diphenylamino)-1-pentene]were successfully obtained.2.The stereoselective coordination copolymerizations of propylene with amino functional monomer 4-(7-octen-1-yl)-N,N-diphenylaniline and 9-(10-undecenyl)-carbazole were described.A new family of functional i PPs with high molecular weight(up to 59?10⁴)and functional groups up to 13.5 mol%were obtained via the direct copolymerization using the same dimethyl(pyridylamido)Hf catalyst system with very high activity(up to 74.4?10⁵g_polymer mol Cat.^-1h^-1).These copolymers exhibit very high thermal stability(T_d>452°C)and surface properties of the all i PP copolymers were evidently improved by introducing functional amine groups,as revealed by the contact angle measurement.Besides,mechanical properties of the functional i PP copolymers could be easily tuned by the comonomer structure or incorporation to fit different application requirements.In summary,efficient syntheses of tertiary amine containing i PP copolymers via efficient direct copolymerization under mild conditions have great potential in improving i PP's properties and developing novel functional i PP materials.The thesis provides a method to study on the functional performances of these well-defined iPP polymers.