Exploration of Ammonia Resistance of Copoly(phthalazinone biphenyl ether sulfone)and Polyetherimide
To investigate the ammonia resistance of copoly(phthalazinone biphenyl ether sulfone)(PPBES)and polyetherimide(PEI),the effects of ammonia solution and ammonia gas on the chemical structures,mechanical properties and intrinsic viscosities of PPBES and PEI were investigated by Fourier transform infrared spectrometer,universal material testing machine and Ubbelohde viscometer.The results show that the imide ring degradation of PEI occurs in ammonia solution and ammonia gas.After soaked in ammonia solution,the mechanical properties and intrinsic viscosity of PEI reduce,and the homogeneous membrane even breaks.After 30 d in ammonia gas,PEI degrades from a solid homogeneous membrane to a viscous liquid with poor ammonia resistance.However,the chemical structures of PPBES in ammonia solution and ammonia gas do not change significantly.After soaked in ammonia solution,the elongation at break of PPBES decreases from 15.8%to 13.6%,the tensile strength decreases from 71.6 MPa to 68.5 MPa,and the intrinsic viscosity decreases from 0.70 dL/g to 0.55 dL/g,but the decline is less than PEI.The intrinsic viscosities of PPBES before and after being placed in ammonia for 30 and 60 d are 0.70-0.73 dL/g,showing no significant change,and the tensile strength decreases from 71.6 MPa to 66.5 MPa,the elongation at break increases from 15.8%to 20.3%.Compared with PEI,PPBES has better ammonia resistance.
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