Synthesis And Application Of Silicone-Containing CO₂-Based Polycarbonate

CO₂ is the most prevalent greenhouse gas in the atmosphere and it is one of the main waste gases emitted in modern industry.Therefore,the use of CO₂ as carbon and oxygen resources is particularly important to relieve current serious environmental problems.With the research on CO₂ utilization,it has been widely used in the preparation of chemical products such as urea,methanol,salicylic acid,and CO₂-based polycarbonate,etc.Among them,CO₂-based polycarbonate was considered as one of the most promising routes to utilize CO₂ resources,but for decades the main research in this field was focused on the preparation of highly active catalysts,the available epoxides are relatively few,the most frequently used epoxides are still propylene oxide and cyclohexene oxide.The mechanical and thermal properties of polycarbonates which prepared by these two epoxides have numerous shortcomings which limits the industrial application and promotion.So,we chose the2-（3,4-epoxycyclohexyl）trimethoxysilane which containing methoxysilane group and propylene oxide as epoxides to prepare a series of silicon containing CO₂-based polycarbonate,and explored the properties and applications of the materials after hydrolysis and condensation reaction with post-modifiable side chain methoxysilane group.1.Preparation of CO₂-based terpolymers using 2-（3,4-epoxycyclohexyl）trimethoxysilane as epoxide.A series of silicon-containing CO₂-based polycarbonates were prepared by adjusting the feeding ratio of TMSO and PO,reaction time and other conditions.The thermal,mechanical and surface properties of the copolymers were determined by differential scanning calorimetry,thermogravimetric analysis,universal testing machine and contact angle measuring instrument.The results show that the TMSO effectively enhances the thermal stability and surface properties of the polycarbonate,and the mechanical properties show a regular of increasing and then decreasing with the TMSO feed ratio increases.We also investigated the hydrolysis and condensation of methoxysilane groups under mild conditions and found that micro-crosslinked structures were formed which obviously enhanced the mechanical properties of the polycarbonate.2.The silicon-containing CO₂-based polycarbonate was used as macromolecular coupling agent for surface modification of ultrafine Ca CO₃,and then explored its application in PPC composites.This macromolecular coupling agent was grafted onto the surface of Ca CO₃ by hydrolysis and condensation of methoxysilane groups,and the successful grafting was demonstrated by thermogravimetric analysis,fourier transform infrared spectrometer and scanning electron microscope.The composites were prepared by melt blending the modified Ca CO₃ with PPC.The thermal and mechanical properties of PPC/Ca CO₃ composites were determined by universal testing machine,impact testing machine,differential scanning calorimetry and thermogravimetric analysis.The modified Ca CO₃ has excellent dispersion in the PPC matrix and enhancing the mechanical and thermal properties of PPC while effectively reducing the cost of preparing PPC composites.