Optimization Of Synthetic Processes For Polyphosphazene Derivatives Containing Reactive Groups And Its Functional Research

Polyphosphazenes are novel organic-inorganic hybrid material containing alternative single and double bonds between phosphorus and nitrogen in the main chain and outer chlorines atoms.The desired organic groups can be introduced into polydichlorophosphazenes through the nucleophilic substitution of chlorine atoms and incoming groups.A variety of corresponding reactive groups can also be designed according to the desired application.Therefore,polyphosphazenes can form a variety of polymers through organic synthesis.Due to the diversity of substituent groups,the polyphosphazene materials have variable properties.Combining the characteristics of phosphorus and nitrogen in the polyphosphazene backbone,the polyphosphazene materials showed excellent flame retardant and thermal properties.Herein,we designed three reactive groups such as carboxyl,amino,and aldehyde to introduce into polyphosphazenes.Polybis(4-ester-phenoxy)phosphazene(PBEPP),polybis(4-carboxyphenoxy)phosphazene(PBCPP),poly(esterphenoxy/phenoxy)-phosphazene(PEPPP),poly(carboxylphenoxy/phenoxy)phosphazene(PCPPP),polybis(4-nitro-phenoxy)phosphazene(PBNPP),poly(nitrophenoxy/phenoxy)-phosphazene(PNPPP),poly(aminophenoxy/phenoxy)phosphazene(PAPPP)and poly(aldehydephenoxy/trifluoroethoxy)phosphazene(PAP TP)were successfully synthesized.Various polyphosphazene derivatives containing amino groups were prepared by varying the proportion of amino groups.The structures and properties were verified by NMR spectrometer(NMR),infrared spectrometer(ATIR),thermogravimetric analyzer(TGA)and other characterization methods.Heteroatoms(P,N,O)doped carbon materials can be synthesized by polyphosphazenes.The resultant materials could enhance the performance of pseudocapacitors.It is also well established that such carbon materials promised a variety of holes.These holes are more conducive for the transmission of ions in the channel and improve the double layer capacitance.Polybis(4-carboxyphenoxy)phosphazene reacted with diphenylmethane diisocyanate(MDI)and further carbonized to prepare porous carbon materials.The morphologies and structures were studied by XRD,Raman,SEM,XPS and other characterization methods.The electrochemical performances were investigated by cyclic voltammetry(CV),galvanostatic charge-discharge(GC)and other electrochemical performance tests.Polyphosphazene containing carboxyl group can be used to modify the epoxy resins and improve their thermal and flame-retardant properties.We used polybis(4-carboxyphenoxy)phosphazene and poly(carboxyphenoxy/phenoxy)phosphazene respectively as curing agents to modify epoxy resins.Also,polybis(4-carboxyphenoxy)phosphazenes and diaminodiphenylmethane(DDM)as composite curing agents to modify the epoxy resins.The resultant modified resigns showed improved thermal stability and flame-retardant properties.