Preparation And Characterization Of The Five-membered Cyclic Carbonates And Nanocomposites

Carbon dioxide is the main greenhouse gas.With the increasing of the discharging of carbon dioxide as the main greenhouse gas,our life and the production have been affected.We all pay attention to make good use of the carbon dioxide under mild condition.In recent years,much attention has been paid to five-membered cyclic carbonates because of their extraordinarily high optical and thermal properties.In our paper, five-membered cyclic carbonates can be prepared from oxiranes and carbon dioxide under mild conditions.The prospect is extremely good to prepare some advanced materials with the five-membered cyclic carbonates in the future.In our paper,firstly,we synthesized the five-membered cyclic carbonates based on a wide variety of cyclic compounds and we also prepared the polymerization with the synthesized cyclic carbonates.Five-membered cyclic carbonates can react with diamine.So we prepare the polymers by the reaction theory.Based on the theory,we can change the Molecular weight by adjusting the ratio of the blocked compounds and also research the change of the properties.With the increasing of the ratio of the blocked compounds,the molecular weight is decreasing,and the glass transition temperature is also decreasing.The thermal decomposition is decreasing with the increasing of the ratio of the blocked compounds.In our work,we also prepared the inorganic particles/PHU nanocomposites, SiO₂/PHU,halloysite/PHU,Vermiculite/PHU and exfoliated vermiculite/PHU nanocomposites,etc.In the processing of preparing SiO₂/PHU,halloysite/PHU nanocomposites,firstly, the nanocompositewas prepared by the in situ surface-initiated polymerization of a five-membered cyclic carbonate,2,2-bi[p-(1,3-dioxolan-2-one-4-yl-methoxy)phenyl] propane(B5CC) and hexamethylene diamine,from the surfaces of the aminopropyl nanoparticle.s The thermal decomposition behavior of the polymers was evaluated by TGA. When the inorganic particles were added into the polymers,thermal decomposition behavior of the polymers was increasing,and the aggregates of the particles were better.We also prepared two kinds of vermiculites/PHU nanocomposites in our paper by intercalating and exfoliating vermiculite.Comparing with the two kinds of composites,the results of the latter is better on the thermal decomposition.The pristine vermiculites can be exfoliated by the two kinds of ways and can also dispersed well.