Characterization And Synthesis Of Polycarbonate By Click Chemical

With the gradual deepening of people’s understanding of petroleum resources and the improvement of environmental awareness,they have gradually realized the limited nature of petroleum resources.Oil resources are non-renewable resources.When they are used up,new renewable resources are needed to replace oil resources.Petroleum-based polymers have good physicochemical properties,are ubiquitous in our daily lives,and have a wide range of applications.The output of polycarbonate is second only to that of polyamide,and polycarbonates is applied in the fields of electronics,electrical,automotive,construction,office machinery,packaging,etc.At the same time,polycarbonate is a green polymer material with good biodegradability and biocompatibility,so research on polycarbonate has always been a hot topic.For the preparation of polycarbonate,although the traditional preparation method can produce polycarbonate better,the preparation process uses toxic gas phosgene,which is not only harmful to humans,but also harmful to the environment.Therefore,new preparation strategies are needed to replace the traditional preparation methods.In this paper,based on the capture of carbon dioxide in the presence of a strong base,the polymerizable carbonate monomer is prepared,and then the polycarbonate material is prepared by thiol-ene click polymerization.The specific research contents are as follows:（1）Based on the presence of strong base,the diol monomer was used to efficiently capture the carbon dioxide in situ,and the polymerizable carbonate monomer was constructed.The structure of the monomer was identified by NMR and FTIR.The effects of reaction temperature,pressure,time,type of strong base,amount of haloalkane and the length of carbon chain of haloalkane on the reaction were studied.And the catalytic effects of different organic bases are compared.Among them,1,1,3,3-tetramethylguanidine（TMG）shows the best catalytic activity.The yield of the obtained polymerizable carbonate monomer is the highest,and the yield of the monomer decreases as the temperature increases.The yield of the cabonate monomer increase with the increase of the CO₂ pressure and the reaction time.For the halogenated alkane to be used in an amount of 3 times the mole of the hydroxyl group of the diol monomer,reducing the amount of the halogenated alkane also greatly reduces the yield of the monomer.As the alkyl chain of the halogenated alkene increases,the yield of the monomer also decreased significantly.By selecting different diol monomers,it is possible to construct diol-based carbonate polymerizable monomers having different structural characteristics,providing a versatile structure for the monomer structure.（2）Based on the structural characteristics of the polymerizable carbonate monomer,the polycarbonate material is prepared by the thiol-ene click chemistry with the dimercapto compound under ultraviolet irradiation,and the obtained polycarbonate has a moderate molecular weight and a high thermal decomposition temperature.Studies have shown that with the increase of the carbon chain of carbonate monomers,the molecular weight of polycarbonate is improved,and the thermal stability is also improved.The main reason is that the increase of the flexible chain makes it easier for the molecular chain to move in order and form crystallization,which improves the overall thermal stability of the polymer.The glass transition temperature（T_g）increases with the decrease of the carbon chain.Based on the polycarbonate-containing thioether structure,the thioether can be further oxidized to increase the glass transition temperature of the polymer,and the glass transition temperature and melting temperature（T_m）are both raised to 26 ^oC and175 ^oC,respectively.This paper provides a new strategy for the preparation of polycarbonate,and can control the structure of polycarbonate by selecting different diol monomers.It provides a new idea for high value utilization of carbon dioxide in situ capture and converts carbon dioxide into polycarbonate with higher value.