Random Copolymerization of Cyclohexene Oxide and Phthalic Anhydride Synergistically Catalyzed by Heterodinuclear Metal Complex
The ring-opening copolymerization of epoxides and cyclic anhydrides constitutes a straightforward route for synthesizing polyesters.The resultant copolymers are mainly obtained with alternating structures,which might limit their application situations due to their low toughness caused by the high density of ester group.It has been demonstrated that the incorporation of ether segments into the mainchain of polyesters is an efficient strategy to tune the thermal and mechanical properties of polyesters,which is greatly limited by the lack of efficient catalyst.In response to these issues,this study proposed to achieve the random copolymerization of cyclohexene oxide(CHO)and phthalic anhydride(PA)to prepare poly(ether-ester)s via the hetero-bimetallic synergistic catalysis strategy.A series of heterodinuclear Al-K complex has been designed for catalyzing the copolymerization of CHO and PA.The structures of the resultant copolymers are confirmed as poly(ether-ester)s using nuclear magnetic resonance spectroscopy and electrospray ionization mass spectrometry.The exploration of the polymerization process further revealed the randomly structure of obtained poly(ether-ester)s,that is,ester and ether segments were randomly distributed in the polymer mainchain.Systemic studies on the effects of ligand structure,metal ions,reaction temperature and catalyst concentration on the copolymerization were explored,indicating that it is the synergistic cooperation between two metal centers that results in the formation of random copolymers.In addition,thermal property characterization of resultant copolymers indicates that the incorporation of polyether segments into polyester could effectively tune their glass transition temperatures,thus enriching the application of polyester materials.
Poly(ester-ether)sHeterodinuclear metal complexRing-opening copolymerizationRandom copolymer
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