New Polymerizations Based On Green Monomers And Triple-bond Monomers

The rich and abundant natural resources offer diverse material foundations for the development of polymer science.It is significant and challenging to use renewable resources as green monomers to construct functional polymers.Among various renewable monomers,carbon dioxide(CO₂)and water(H₂O),as abundant,cheap and nontoxic green monomers,have attracted much attention.Triple-bond building blocks show versatile properties owing to their electronically unsaturated structures.Polymers prepared from triple-bond building blocks have electronically unsaturated bonds or aromatic rings in their backbones,which behave fascinating photoelectric properties.These polymers have broad application prospects in the field of optoelectronics.From the viewpoint of green chemistry,combining abundant and renewable green monomers with chemically active triple bond building blocks to prepare new functional polymers has been one of the research goals of our group.In this thesis,we focus on the development of new polymerizations based on green monomers(CO₂ and H₂O)and triple-bond building blocks(isocyanides and alkynes)towards a series of new functional polymers and exploration of the properties of polymers.The detailed research contents are as follows:First,the monomers of bis(2-iodoaniline)s were prepared for the first time and a new polymerization of CO₂,isocyanides and 2-iodoanilines under atmospheric pressure was successfully established.A series of heterocyclic polymers containing benzoyleneurea were obtained under mild conditions.Thanks to the formed amide groups in the heterocyclic units in the main-chains,the resultant polymers could self-assemble into spheres with sizes between200 and 1000 nm.The polymerization has good functional group tolerance.The polymers containing tetraphenylethylene(TPE)units show the unique aggregation-enhanced emission(AEE)features,which could be used to visualize the self-assembly process and morphologies under UV irradiation,and serve as fluorescence probes to selectively and sensitively detect Au³⁺ions.In addition,single crystal structures of model compounds containing cis-and trans-TPE units illustrated that the corresponding polymers exhibited different behaviors in AEE properties,self-assembly and limit of detection for Au³⁺ions due to the different intermolecular hydrogen bonding interactions.Second,we developed an efficient polymerization of CO₂,2-alkynylanilines and aryl iodides.The polymerization was facilely carried out under atmospheric CO₂ and fused-heterocyclic polymers containing quinolinedione with high molecular weights(M_w up to240300)and well-defined structures were generated in high yields(up to 95%).The in-situ FT-IR could monitor the concentration of carbonyl group on the newly formed heterocyclic ring,which further confirmed the reaction kinetics.The prepared fused-heterocyclic polymers possess good solubility,thermostability and film-forming ability.The films show good transparency,high refractive index and low dispersion.Furthermore,the intermolecular hydrogen bonding interactions of the amide groups in the fused-heterocyclic units made them self-assemble.Different self-assembly morphologies could be obtained by varying solvents and sample preparation methods.This work establishes a new strategy for the preparation of polymers with high refractive index from CO₂.The films of polymers have potential applications in the field of optical lenses.Finally,we chose H₂O,which is more abundant,cheap and non-toxic natural resource,as the green monomer,and developed an efficient polymerization of H₂O,terminal alkynes and isocyanides,which provided a series of poly(alkynamide)s with high molecular weights(M_wup to 161500)in high yields.The prepared poly(alkynamide)s show good solubility and thermal stability.By systematically studying the reaction conditions of this polymerization,we found that when the amount of water added was 10 equiv.of terminal alkynes monomers,the better polymerization result could be obtained.The in-situ FT-IR could be used to monitor the change of carbonyl group in the amide structure during the reaction,which revealed dynamic process of this polymerization reaction and suggested that the polymerization took place smoothly.The amide groups in the structures of polymers endow them with self-assembly.Polymers showed different assembled behaviors via different solvents and sample preparation methods.This is a new method to construct poly(alkynamide)s directly from terminal alkynes and H₂O under mild conditions.