The lead p-aminobenzoic acetate (ABA(Pb)) was synthesized via ion exchange method

and then lead-ion-containing polyamide acid (PAA(Pb)) and polyimide (PI(Pb)) were prepared by a two-step polycondensation approach

starting with ABA(Pb) and 2

2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) as the diamine monomers

2

2-bis[4-(3

4-dicarlxyphenoxy)phenyl]propane dianhydride (BPADA) as the dianhydride monomer in N-methyl-2-pyrrolidinone (NMP) solvent.ABA(Pb)

PAA(Pb) and PI(Pb) are fully characterized by Fourier transform infrared (FTIR) spectroscopy

proton nuclear magnetic resonance spectroscopy (1H-NMR) and elemental analysis.X-ray diffraction analysis (XRD)

thermogravimetric analysis (TGA)

mechanical tests and -ray spectrometry are used to respectively investigate the chemical structure

thermal stability

mechanical property and radiation-proof property of PI(Pb) materials.Compared with pure polyimide material (PI) and PI-Pb(NO3)2 material which is prepared by physically mixing with equal amount of lead element

PI(Pb) material possesses the highest radiation shielding rate and lowest half-value thickness toward radioactive 60Co and 137Cs sources.It demonstrates that PI(Pb) material exhibits the best -ray radiation-proof property.The key reason is that the lead ions are chemically bonded into the polyimide main chain of PI(Pb)

which can achieve a high dispersion of lead ions distributed in the matrix.As a result

an increased probability of -ray interacting with lead atoms helps improve the radiation-proof property of PI(Pb) material.In conclusion

PI(Pb) material not only exhibits a good thermal stability and a good mechanical property

but also has the best -ray radiation-proof property

and thus becomes a promising light weight -ray radiation-proof material.