Synthesis And Properties Of Silane-functionalized Polythioethers Via Thior-yne Click Reaction

In the field of polymer chemistry,one key research topic is developing chemical reactions which are rapid,efficient,mild,simple and easy to handle.Click reactions have all these advantages.Although the concept of click reaction has only been introduced for more than ten years,it has shown great potent and practical value in many scientific research fields due to its advantages of high reaction rate,excellent chemical selectivity,mild reaction conditions,simple experimental steps,high chemical reaction yield and so on.As a kind of click reactions,thiol-yne reaction also has these advantages and has played an important role in many applications such as surface modification,polymer synthesis and post-functionalization,and coating and gel synthesis.Polythioether,as an important functional material,has many excellent physical and chemical properties,such as superior chemical stability,thermal stability,corrosion resistance and mechanical properties.It has been widely used in many fields,such as medical materials,energy storage materials,optical devices,anti-corrosion equipment and so on.The introduction of silyl groups to polythioether molecules will produce functional polymers with novel properties.However,it is difficult to introduce silyl groups into polythioether molecules by conventional synthesis methods.To meet this challenge,we aim to develop thiol-yne reaction for the synthesis of silicon-containing polythioether.In this paper,we designed and synthesized silane modified polythioethers based on thiol-yne click reaction,and studied their properties and application.The main research contents are as follows:1.A series of polythioethers with silyl groups were successfully synthesized by thiol-yne click reaction of different dithiols with alkynylsilanes.Their structures were characterized by NMR and FT-IR spectra.The properties of the products were characterized with fluorescence,GPC,TGA,and DSC.It was found that these polythioethers with silyl groups emit strong blue fluorescence,therefore they can be used in blue light emitting materials.This part of work will provide synthetic strategy to synthesis polythioethers with silyl groups.2.To demonstrate the unique effect of silyl groups on the properties of polythioehter,a series of polythioethers with tert-butyl groups were synthesized by thiol-yne click reaction at room temperature.Their structures were characterized by NMR and FT-IR,and their properties were investigated with fluorescence,GPC,TGA,and DSC.In contrast to polythioethers with silyl groups,this series of polymers don't have any fluorescence.This phenomenon is due to the unique S?Si coordination bond in former polymers,which acts as unconventional chromophore.Moreover,compared with polythioether with tert-butyl groups,the introduction of trimethylsilyl groups can effectively lower the glass transition temperature and improve the refractive index of the polymer materials.These conclusions can provide important theoretical basis for the design of new polymer materials with low Tg or high refractive index.3.Based on the coordination of polythioether P3 with copper ions,polymer networks with different metal proportions were prepared.UV and EDS anlysis demonstrated the successful coordination between polythioether and copper ion.Their thermophysical properties were tested with TGA and DSC.Especially through DSC test,it was found that the thermophysical properties of polymer coordination network can be effectively controlled by adjusting the proportion of metal salts.The part of work lays a theoretical and experimental foundation for the development of new supramolecular plastics and elastomers.