Preparation And Study Of Polyimide-Crown Ether Composite Films With Nanoparticles

Recently,polyimide complex films interlocked with crown ether(PI[CE])was proved to possess improved strength and toughness.However,the thermal stability was deteriorated as the films exhibited reduced 5% weight loss temperature(Tdec)and glass transition temperature(Tg),but higher coefficient of thermal expansion(CTE)value,which limited the further application of this material.The above problems could be sucessfully ameliorated by the incorporation of inorgainic nanofillers.Based on this,montmorillonite and graphene oxide were introduced into the above matrix to prepare nanoparticle/PI[CE] nanocomposite films,respectively.And their effects on the performances of the films were investigated.1.Organically modified montmorillonite(OMMT)was introduced into PI[CE] matrix via solution blending method to obtain OMMT/PI[CE] nanocomposite films.The results revealed that OMMT/PI[CE] nanocomposite films had better thermal stability compared with PI[CE] complex.When the loadings of OMMT reached 3 wt%,Tdec and Tg value of the film increased from 539.2°C and 335.0°C of PI[CE] to 549.8°C and 358.2°C,respectively,and CTE value decreased from 51.1 ppm/K to 17.9 ppm/K.Meanwhile,the nanocomposite films showed outstanding reinforcement in mechanical performances.The Young's modulus and tensile strength of OMMT-3/PI[CE] increased from 3.17 GPa and 103.8 MPa of PI[CE] to 3.65 GPa and 124.5 MPa,respectively.And its elongation at break and toughness increased from 21.9% and 18.8 MJ/m3 to 29.8% and 30.8 MJ/m3,respectively.2.Well-dispersed polyvinylpyrrolidone modified graphene oxide solution(PGO)was introduced into PI[CE] matrix via solution blending method to obtain PGO/PI[CE] nanocomposite films.The results revealed that PGO/PI[CE] nanocomposite films had better thermal stability compared with PI[CE] complex.When the loadings of PGO reached 0.3 wt%,10% weight loss temperature(Td10%)and Tg value of the film increased from 568.5°C and 335.0°C of PI[CE] to 581.2°C and 347.5°C,respectively,and CTE value decreased from 51.1 ppm/K to 30.5 ppm/K.Meanwhile,the nanocomposite films showed remarkable reinforcement in mechanical performances.The Young's modulus and tensile strength of PGO-3/PI[CE] increased from 3.17 GPa and 103.8 MPa of PI[CE] to 3.77 GPa and 136.8 MPa,respectively.And its elongation at break and toughness increased from 21.9% and 18.8 MJ/m3 to 49.0% and 53.5 MJ/m3,with an outstanding enhancement of 124% and 184%,respectively.3.To sum up,two kinds of nanocomposite films revealed improved overall perforamnces compared with PI[CE] complex.And OMMT had more significant amelioration effect on thermal performances on the nanocomposite films,while PGO contributed more to the mechanical properties.