Development Of New Catalytic System And New Reaction For Alkyne-based Polymerization

New and powerful polymerization reactions have provided abundant polymeric materials.Developing new alkyne-based polymerizations,especially the Cu?I?-catalyzed alkyne-azide click polymerizations has been a hot research topic because from these polymerization,polymeric materials with new structures and advanced functions will be generated.However,the conventional Cu?I?catalysts for the alkyne-azide click polymerization can be used for only once,which are not green and sustainable.Hence developing new catalysts that are capable of being recycled and reused became very important.The emergence of Cu nanoparticles and supported Cu?I?catalysts,not only provides an innovative idea for the separation and recovering of catalysts for alkyne-azide click polymerization,but also could lower the copper residual in the polymeric products.Moreover,to enrich the family of alkyne-based polymerization,it is also important to develop new powerful polymerization reaction.Alone this line,this thesis reports following innovatinve works.First,Cu nanoparticles were prepared according to literatures and were first used for catalyzing the alkyne-azide click polymerization.Under the optimized reaction conditions,the Cu nanoparticles catalyzed alkyne-azide click polymerization could generate,1,4-regioregular polytriazoles with weight-average molecular weight up to 154000 g/mol in high yields.Moreover,the Cu nanoparticles can be recycled and reused for 11 times.Second,we prepared a Cu?I?containing magnetic catalyst for the alkyne-azide click polymerization.On magnetic nanoparticles Fe₃O₄/SiO₂ surface,Cu₂O nanoparticles were immobilized by in situ reduction of Cu?II?,forming Fe₃O₄/SiO₂/Cu₂O nanoparticles.Such magnetic nanoparticles could be used for catalyzing the click polymerization,yielding1,4-regioregular polytriazoles with weight-average molecular weight up to 132600 g/mol in the yields up to 89%.After polymerization,the magnetic nano catalyst can be separated from the reaction solution by a magnet,which greatly simplifies the experimental operation.These recycled Fe₃O₄/SiO₂/Cu₂O nanoparticles can be reused for as many as 12 times.Moreover,he copper residuals in the resultant polymers are much lower than those catalyzed by convetional Cu?I?catalysts.Third,based on the atom transfer radical addition?ATRA?reaction of alkyne by activated helogen,an aromatic alkyne-based ATRA polymerization was developed,and the polymer with weight-average molecular weight up to 17900 g/mol can be produced in a yield of 94%.According to the structural characterization results,newly formed polymer comprised mainly by the E-isomers.Thus,this polymerization is also stereoselective.Forth,to utilize the localized surface plasmon resonance?LSPR?photothermal effect for mediating the click polymerization of activated alkyne and azide,SiO₂ encapsulated Au nanorods?AuNRs?were synthesized.The resultant AuNRs/SiO₂ can be dispersed in organic solvents,and realized the catalyzing of the click polymerization of activated alkyne and azide under the irradiation of 808 nm laser light.Polytriazoles with weight-average molecular weights up to of 66500 g/mol can be produced in yields up to 84%.The ratio of 1,4-and1,5-regioregular triazole isomers in the polymers were deduced to be as high as 85.5%,exhibiting a good selectivity.Moreover,these results are quite similar with those of metal-free alkyne-azide click polymerization initiated by the heating.But the method in this work is theoretically controllable spacially and is expected to be broadly applied in diverse areas.