Synthesis Of Phosphorus Diamine Monomer With Asymmetric Structure And Preparation Of Polyimide Film Materials

In this paper,the synthetic methods of 4-amino phenyl-3,5-diethyl-4-amino phenyl-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-phosphoryl ethane(ADADOPPE)have been developed.The optimal conditions were obtained by orthogonal experiments,and the optimum reaction conditions were:the reaction temperature was 130°C,the reaction time was 20h,the amount of 2,6-diethylaniline was 3 times of the molar amount of DOPO,and the amount of p-toluenesulfonic acid was 4%of the DOPO mass.The experimental yield was 60.0%under optimal conditions.The structure of ADADOPPE was characterized by FT-IR and ~1H-NHR and the melting point of the monomer was determined to be247.9°C by DSC.A seiries of AAPBO/?-BPDA/BPADA polyimide films were synthesized by two-step method with 2-(4-aminophenyl)-5-aminobenzoxazole(AAPBO)and two dianhydride monomers of BPADA and?-BPDA by different molar ratios.The viscosity of the polyamide acid was tested by DHR.The structure of the films was characterized by FT-IR,the thermal properties were tested by TMA and TG,and the solubility,water absorption and flame retardancy,mechanical properties and optical transmission performance were also tested.It was found that the viscosity of the films were high;the glass transition temperature was 247.26~290.99°C,the thermal decomposition temperature was 538.0~630.4°C,the carbon residual mass was 59.41~65.22%when the temperature rised to 800°C,the coefficient of thermal expansion was very low,which indicated that the films had good heat resistance and thermal stability;the films was substantially insoluble in conventional organic solvents;the water absorption rate was 0.22~1.44%;the limited oxygen index was 35~55%;tensile modulus was 3014.52~9765.49MPa,tensile strength was 128.80~343.93 MPa,which showed the films had excellent mechanical properties;UV maximum transmittance was 80.49~85.44%,cutoff wavelength was 377.5~430.0 nm,which indicated that the optical transmission properties of the film is good.Two series of films were prepared by copolymerization of different molar ratios of ADADOPPE and AAPBO,with dianhydride monomer BPADA or?-BPDA.It was found that the changes of the performances from the films of AAPBO/BPADA to the copolyimide films of ADADOPPE/AAPBO/BPADA after adding ADADOPPE:the viscosity of the PAAs were reduced,but within 10%of the addition amount did not affect the film forming capacity;the glass transition temperature was 231.84~244.32°C,the thermal decomposition temperature was 545.7~546.1°C,the carbon residual mass was 56.69~57.86%when the temperature rised to 800°C,the thermal stability was basically unchanged,nor the coefficient of thermal expansion;the solubility in some conventional organic solvents was improved;the water absorption rate increased,the highest was 0.62%,which indicated that the films had a very low water absorption ability;the Limited Oxygen Index was higher than 60%,which showed excellent flame retardant performance;tensile modulus was 2898.90~3244.63 MPa,tensile strength was 94.40~123.11 MPa,mechanical properties had weakened;the optical transmission performance had improved.It was also found that the changes of the performances from the films of AAPBO/?-BPDA to the copolyimide films of ADADOPPE/AAPBO/?-BPDA after adding ADADOPPE:the viscosity of the PAAs were reduced,but within 10%of the addition amount did not affect the film forming capacity;the glass transition temperature was 310.09~321.81°C,the thermal decomposition temperature was 634.9~635.1°C,the carbon residual mass was 64.38~64.60%when the temperature rised to 800°C,the thermal stability was enhanced,the coefficient of thermal expansion changed little;the solubility in some conventional organic solvents was improved;the water absorption rate changed little,which indicated that the films had a very low water absorption ability;the limited oxygen index was higher than 60%,which showed excellent flame retardant performance;tensile modulus was 6250.98~10028.56 MPa,tensile strength was 136.35~22.43 MPa,mechanical properties had weakened;the optical transmission performance had improved.