The Synthesis And Application Of The Fluorine-containg Polyimide

In this paper, a series of fluorine-containing monomer were prepared by using hexafluoropropylene oxide to incorporate fluorine atom into the monolithic structure. Based on this monomers different fluorine-containing polyimide polymers were synthesized and characterized the structure and performance.Based on hexafluoropropylene oxide as material, hydrogen fluoride as catalyst, hexafluoroacetone(HFA) was prepared. The effect of catalyst, reaction temperature and reaction time on the HFA conversion were also studied, and the best synthetic conditions of HFA were obtained. As follows:hexafluoropropylene oxide110g, catalyst100g, reaction temperature100℃,and reaction time about15h.Based on HFA and o-xylene as material,2,2-Bis(3,4-Dimethylphenyl)hexafluoropropane was prepared in the high pressure resistant and corrosion resisting agitated reactor. Then2,2-Bis(3,4-Dimethylphenyl)hexafluoropropane was oxidized by using potassium permangan-ate under alkaline conditions to obtain2,2-Bis(3,4-dicarboxyphenyl)hexafluoro propane, then dehydration, Vacuum distillation and other steps to obtain2,2-Bis(3,4-anhydrodicarboxy phenyl)hexafluoropropane. The structure of2,2-Bis(3,4-Dimethylphenyl)hexafluoropropane,2,2-Bis(3,4-dicarboxyphenyl)hexafluoropropane and2,2-Bis(3,4-anhydrodicarboxyphenyl)-hexafluoropropane were confirmed by means of IR spectroscopy,19F NMR spectroscopy and1H NMR spectroscopy. And then use the liquid chromatography test the purity of the2,2-Bis(3,4-anhydrodicarboxyphenyl) hexafluoropropane.Based on HFA and benzene as material, hexafluoro-2,2-diphenylpropane was prepared. Then nitrified to obtain2,2-bis(3-nitro phenyl)hexafluoropropane and the polyimide monomer of2,2-bis(3-Aminophenyl) hexafluoropropane was obtained in the presence of FeCLa/C and hydrazine monohydrate. The structure of hexafluoro-2,2-diphenylpropane,2,2-bis(3-nitro phenyl)hexafluoropropane and2,2-bis(3-Aminophenyl)hexafluoropropane were confirmed by means of IR spectroscopy,19F NMR spectroscopy and1H NMR spectroscopy. And then use the liquid chromatography test the purity of the2,2-bis(3-Aminophenyl)hexafluoropropane.Based on different diamine monomers and pyromellitic dianhydride as material, different Polyamide acid was prepared in the solvent of DMAc. The different diamine monomers as follows:1,2-diaminobenzene, m-Phenylenediamine, p-Phenylenediamine,4,4`-diaminodiphenyl ether and other diamine monomers.The effect of Charging method, monomer ratio,reaction temperature and reaction time on the molecular weight of the Polyamide acid were also studied, and the best synthetic conditions of the high molecular weight of the Polyamide acid were obtained. As follows:diamine monomer add first, sDMAc as solvent,the monomer ratio as1.02:1, reaction temperature10℃,and reaction time about6h.Based on2,2-Bis(3,4-anhydrodicarboxyphenyl)hexafluoropropane, p-Phenylenediamine and2,2-bis(3-Aminophenyl)hexafluoropropane as material, hexafluoro fluorine-containing polyimide polymers and bishexafluoro fluorine-containing polyimide polymers was prepared in solution. The glass transfer temperature and thermal property of fluorine-containing polyimide polymers were characterized by Differential Scanning Caborimetry (DSC) and Thermogravimetry (TG), respectively.