Novel Semi Crystalline, Soluble and Magnetic Poly(imide-ether)/Zeolite Nanocomposites: Synthesis, Characterization and Computational Study

Abstract

In this research new magnetic and semi crystalline poly(imide-ether)/zeolite nanocomposites were successfully fabricated via solution intercalation technique. For this purpose, novel functional diamine monomer, 4-(bis (4-(4-aminophenoxy)-2,5-dimethylphenyl) methyl)-N,N-dimethylbenzenamine (5), containing flexible ether, methyl and dimethylamino groups was successfully synthesized via three step reactions. The synthesized diamine (5), was used to prepare related soluble aromatic poly(imide-ether) (PIE) as a source of polymeric matrix by reaction with benzophenone-3,3′,4,4′-tetracarboxylic dianhydride. The synthesized PIE was assessed by Fourier transform infrared and nuclear magnetic resonance (¹H-NMR) techniques. The synthesized PIE revealed good solubility in dipolar aprotic solvents at room temperature. The molecular geometry and electronic properties of PIE units in the ground state by DFT and B₃LYP method with 6-31G (d) as basis set were studied. Due to incorporation of N,N-dimethyl amino group as an electron donor on the benzene ring in the structure of PIE, the highest occupied molecular orbitals (HOMO) are localized mainly on N,N-dimethyl aniline. The calculated energy values of HOMO and LUMO were − 5.48 and − 3.02 eV, respectively. Also, the HOMO–LUMO gap value of the studied PIE is − 2.06 eV which show PIE units having a small energy gap and are known as soft molecule. Nanozeolites ZSM-5 which synthesized from hydrothermal treatment was magnetized via chemical co-precipitation and used for preparation of new poly(imide-ether)/zeolite nanocomposites (PIEN 3% and PIEN 5%). The nanostructure and different properties of the nanocomposites were examined using transmission electron microscope, X-ray diffraction (XRD), ultraviolet–visible, gravimetric analysis (TGA), derivative of thermogravimetric, differential scanning calorimetry and vibrating sample magnetometer. The results of XRD studies illustrated that novel synthesized PIE and their nanocomposites exhibited a semi crystallinly pattern in X-ray diffraction analysis. The crystalline morphology of samples might be because of chain packaging of PIE and good intermolecular interaction of polymer chains due to presence of N,N-dimethylamine. In examining the optical properties, it has been observed that by increasing the concentration of the nanoparticle, PIEN 3% and PIEN 5% nanocomposites show decrease in wavelength and have a blue shift of 14 and 24 nm, respectively compared to pure PIE. Also, the PIEN nanocomposites under applied magnetic field exhibited the hysteretic loops of the superparamagnetic nature. Results of TGA measurement have shown that addition of MNZ-Fe₃O₄@ZSM-5 in PIE matrix increased the thermal stability, compared to the neat PIE. With increasing the content of MNZ-Fe₃O₄@ZSM-5 to 5 wt% due to agglomeration of nanoparticles T₁₀% decreased slightly. The glass transition temperatures (T_g) of the PIE and their nanocomposites were about 240–255 °C. Briefly, the PIE and their nanocomposites showed high thermal stability while their solubility was improved. These properties will be useful for processing and new applications of poly(imide-ether).