Organosoluble and transparent polyimides derived from alicyclic dianhydride and aromatic diamines

Soluble and processable thermoplastic hybrid polyimides containing POSS in main chains

The combination of 3,13-bis(3-aminopropyl)-double-decker-shaped-silsesquioxane and a fluorinated dianhydride produces a flexible polyimide with a low Tg, high heat resistance, and excellent solvent solubility. The fluorinated dianhydride loosened the interchain packing to suppress CT interactions, leading to the formation of a colorless polyimide.

Optical, thermal and gas separation properties of acetate-containing copoly(ether-imide)s based on 6FDA and fluorenyl diamines

The diamine, 9,9-bis[4-(4-amino-3-hydroxylphenoxy)phenyl]fluorene (BAHPPF) was synthesized by the modified two-step method. Then, a series of acetate-containing copoly(ether-imide)s were prepared by the copolymerization of BAHPPF, 9,9-bis(4-aminophenyl)fluorene (BAF) and 2,2′-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) followed by chemical imidization. The structures and properties of the BAHPPF and copoly(ether-imide)s were characterized by nuclear magnetic resonance spectrometer (NMR), Fourier transform infrared spectrometer (FTIR), X-ray diffractometer (XRD), differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA), ultraviolet-visible spectrophotometer (UV-VIS), and tensile testing. Single gas permeation performances of these copoly(ether-imide)s were also studied for five representative gases of interest including H2, O2, N2, CO2, and CH4. The experimental results showed that the copoly(ether-imide)s showed excellent optical properties with high light transmittance above 80.2% at 450 nm. The glass transition temperature of these copolymers were higher than 333°C. Their tensile strength and Young’s module also increased, and the elongation decreased with the decrease of BAHPPF. High gas permeabilities of copoly(ether-imide)s were obtained, and the ideal selectivity of CO2/CH4 was improved due to the introduction of acetate group and flexible ether linkage. These copoly(ether-imide)s could be applied to the field of optics and gas separation.

Synthesis and properties of transparent polyimides derived from 1,4-cyclohexylene bis(trimellitate anhydride)

A series of polyimides (PIs) derived from 1,4-cyclohexylene bis(trimellitate anhydride) (TACH) was synthesized by conventional two-step method with chemical imidization. The resulting PIs had glass transition temperatures ( Tgs) in the range of 188–240°C and exhibited good mechanical properties with tensile strengths of 50.0–90.2 MPa, tensile moduli of 2.2–3.9 GPa, and elongations at break of 2.9–5.8%. These PI films showed high optical transparency with cut-off wavelengths of 345–369 nm and high transmittance at 500 nm with more than 84%. Compared with PIs derived from 1,4-bis(3,4-dicarboxyphenoxy)cyclohexane dianhydride, the TACH-based PIs showed higher Tg, better solubility, and competitive transparency.

Colorless polyimides derived from 2R,5R,7S,10S-naphthanetetracarboxylic dianhydride

Colorless polyimides with excellent thermal and mechanical properties were developed from 2R,5R,7S,10S-naphthanetetracarboxylic dianhydride, and their properties were systematically compared with those based on 1S,2R,4S,5R-cyclohexanetetracarboxylic dianhydride.

Synthesis of organosoluble and transparent phenolphthalein-based cardo poly(ether sulfone imide)s via aromatic nucleophilic substitution polymerization

A series of cardo poly(ether sulfone imide)s (PESI-C) containing bulky phthalide groups were prepared via aromatic nucleophilic substitution reaction of phenolphthalein with 4,4′-difluorodiphenyl sulfone and 4,4′-bis(4-fluorophthalimido)diphenyl ether (BFPI). The glass transition temperatures and 5% weight loss temperatures in nitrogen of the resulting PESI-C increased from 258°C to 278°C and from 468°C to 495°C with increasing the content of imide moiety in the polymer chain, respectively. These PESI-C films were transparent and essentially colorless and exhibited good mechanical properties with tensile strengths of 91–124 MPa, elongations at break of 6.9–12.8%, and tensile moduli of 2.2–2.8 GPa, respectively. It is noted that the tensile strengths, elongations at break, and tensile moduli of PESI-C also increased with increasing the content of BFPI in the copolymerization, indicating that the properties could be adjusted by controlling the ratio of BFPI and 4,4′-difluorodiphenyl sulfone.

Monodispersed ultramicroporous semi-cycloaliphatic polyimides for the highly efficient adsorption of CO2, H2and organic vapors

Monodispersed ultramicroporous semi-cycloaliphatic polyimides (sPIs) were synthesizedviasolution polycondensation and possess high uptakes for CO₂, H₂, aromatic and aliphatic vapors, exhibiting potential in gas storage and the recovery of toxic organic vapors.

Synthesis and properties of transparent polyimides derived from trans-1,4-bis(2,3-dicarboxyphenoxy)cyclohexane dianhydride

A series of transparent polyimides was prepared from trans-1,4-bis(2,3-dicarboxyphenoxy)cyclohexane dianhydride (trans-3,3′-CHDPA) with various aromatic diamines via one-step solution polycondensation.

Synthesis and characterization of transparent polyimides derived from ester-containing dianhydrides with different electron affinities

Transparent polyimides derived from ester-containing dianhydrides with different electron affinities were synthesis and the different properties caused by different ester linkages were well investigated.

High organosolubility of novel asymmetric polyimides-containing benzimidazole rings

Two tetramethyl-substituted diphenylmethane diamines, α,α-bis(4-amino-3,5-dimethylphenyl) phenylmethane (BADP) and 3,3′,5,5′-tetramethyl-4,4′-diaminodiphenylmethane (TMDA), were synthesized. Two series of novel soluble polyimides (PIs) with high glass transition temperature ( Tg) were derived from 3,3′4,4′-benzophenone tetracarboxylic dianhydride with 6,4′-diamino-2-phenylbenzimidazole and BADP (or TMDA) via one-pot synthesis using anhydrous N-methyl-2-pyrrolidone as a solvent. Precipitation or gelation does not occur during polymerization and imidization, and the resulting products dissolve well in polar aprotic solvents and phenolic solvents. The two series of PI films have good transparency in the visible light region, with a cutoff wavelength at 365 nm and higher than 50% of the transmittance at 450 nm. Tgs are in the range of 381–431°C, and 10% weight loss in nitrogen occurs above 530°C in all cases. Upon increasing BADP (or TMDA) moieties content, the Tg values decrease, whereas the thermal stability tends to increase. Moreover, the PIs-containing TMDA units have a higher thermal stability than those containing BADP units.

Effect of unsymmetrical spiro dianhydride structure on properties of fully aliphatic polyimides

Structure-property relationship was studied for fully aliphatic polyimides containing alicyclic dianhydride and diamine units. Rel-(1′R,3S,5′S)-spiro[furan-3(2H),6′-[3]oxabicyclo[3.2.1]octane]-2,2′,4′,5(4H)-tetrone (DAn) was used as an unsymmetrical spiro dianhydride, and 1,2,3,4-cyclopentanetetracarboxylic dianhydride (CPDA) and bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BOCA) were used as symmetrical non-spiro dianhydrides. 4,4′-Methylenebis(2-methylcyclohexylamine) (MMCA) and 5-amino-1,3,3-trimethylcyclohexanemethylamine (AMCH) were N-silylated, and reacted with the dianhydrides to prepare the fully alicyclic polyimides. The formation of the polyimides was confirmed by Fourier transform infrared spectroscopy. DAn-based polyimides showed higher solubility than the polyimides derived from CPDA or BOCA. This was explained based on the results of wide-angle X-ray diffraction (WAXD) analysis of the polyimides. The WAXD study showed that DAn-based polyimides have greater full width at half maximum (FWHM) and d-spacing values than the other polyimides. This indicates that DAn-containing polyimides have lower intermolecular order, decreased intermolecular interaction, and less close chain packing compared to the other polyimides. It is considered that the morphology of DAn polyimides is attributable to the unsymmetrical spiro structure of DAn that leads to bulkiness, irregularity, and non-linearity of the polyimide chains. Decomposition temperatures of the polyimides were investigated by thermogravimetric analysis (TGA) and UV-visible spectroscopy was performed to evaluate the optical transparency of the polyimides.

Pendent Polyimides using Mellitic Acid Dianhydride. IV. Effect of Increased Zirconium-Pendent Group Content on Polymer Properties

For co-polyimides (PIs) of mellitic acid dianhydride, 1,3-aminophenoxybenzene and 4,4′-oxydiphthalic anhydride, Zr-pendent group content could be increased to 50% (mol) improving atomic oxygen (AO) resistance while retaining good film properties. Spectral data are consistent with expected structures. Intrinsic viscosities of 0.54—0.60 dL g—1 and average molecular weights of 111 000—122 000 g mol— 1 estimated from gel permeation chromatography confirm the polymeric nature of co-polyamic acid precursors. Nuclear magnetic resonance integrations and amounts of thermogravimetric analysis residue verify pendent group concentrations. Increasing Zr-pendent group concentration from 10 to 50% (mol) caused glass transition temperatures to increase (198—245 °C), decomposition temperatures to decrease (518—455 °C), and the number of film layers able to be fabricated prior to crack formation to decrease (10 to 8). These numbers of layers were much higher than those for other PIs with comparable Zr-pendent group concentrations. Increased pendent group concentration caused the amount of protective oxide layer formed upon AO exposure to increase.

Synthesis and Characterization of Novel Polyimides Containing Anthracene Moiety

A new type of anthracene containing diamine monomer bis (4-amino 3,5 dimethyl phenyl) anthra methane was prepared by adopting a new procedure starting from 9-anthraldehyde and 2,6-dimethyl aniline. The diamine was reacted with a number of aromatic dianhydrides to form polyimides via a two step polycondensation method involving the formation of poly (amic acid) as the first step and the thermal imidization as the second step. During thermal imidization the temperature was increased stepwise leading to the formation of the polyimide in good yield. Films were made from the prepared poly (amic acid). The Tg values of the polyimides were found to be in the range of 265–294°C, the T10 values were in the range of 396–492°C indicating better thermal stability. They were readily soluble in DMAc, DMF, DMSO, THF, CHCl3, m-cresol and pyridine. The tensile properties of the polyimide films are in the range of 66.2–92.3 MPa ensuring good mechanical properties.