Synthesis and characterization of new soluble polyimides based on pyridine unit with flexible linkages

Abstract

A series of new polyimides were synthesized by condensation of pyridine-bridged novel diamine monomers, bis(4-aminobenzoyloxy-3,5-dimethyl phenyl)-3 0 -pyridyl methane and 2,6-bis(2-amino-3-pyridyloxy)pyridine, with various aromatic anhydrides. The monomers and precursors were characterized by elemental analysis, Fourier transform infrared (FTIR), proton nuclear magnetic resonance ( 1 H NMR), and carbon-13 nuclear magnetic resonance ( 13 C NMR) spectroscopic techniques. The structure of the polymers were characterized by FTIR and 1 H-NMR spectroscopy, and the physical properties of the polymers, including the glass transition temperature (in the range of 199-319 C), thermal and thermooxidative stability (10% weight loss temperature is in the range of 375-539 C in air and 403-542 C in nitrogen atmospheres), the char yield in the range of 37.91-56.65% at 800 C, solubility, solution viscosity (0.81-1.81), molecular weight data, optical properties, crystallinity, mechanical properties like tensile strength (86-102 MPa), elongation at break (12.5-16.5%), tensile modulus (1.2-1.8 GPa), and moisture absorption were also studied.

Influence of graphene oxide on thermal, electrical, and morphological properties of new achiral polyimide

“…These polymers have high glass transition temperatures ( T g s) or high melting temperatures ( T m ) and limited solubility in organic solvents which restricts the extended commercial application. Research has been carried out worldwide to overcome these issues by incorporating flexible linkages, asymmetric centres and aliphatic groups . Among these methods introducing aliphatic chain containing monomers in the polymer chains is an effective way to convert polymeric materials to stable forms for improving their solubility which overcomes the processing difficulty.…”

Synthesis and characterization of flexible/stretchable polyimide having long/bulky aryl pendent group and polyimide/silicon dioxide nanocomposites.

“…The aromatic protons appear in the range 110–160 ppm. The resonances at 160.9, 36.2, and 54.3 ppms may be assigned CH = N carbon, methylene group and the –CH group, respectively .…”

“…The bulky poly aryl groups like naphthalene and anthracene caused elevated T g and good thermal and mechanical properties with better solubility in the organic solvents . Our already reported works show that if the polymer chain includes hetero aromatic rings like pyridine , triazole , quinoline , in the main chain, thermal stability will be very high. Inclusion of long and bulky multiple alkyl side chains impart extra solubility, toughness, flexibility, and good elongation even above 200%, that is, elastomeric properties in the polyimides but with inferior thermal and mechanical properties .…”

Nanocomposites of a new organosoluble polyetherimide and epoxide‐functionalized magnetite for removal of Co(II) Ions: Kinetic and thermodynamic investigations

“…Introduction of flexible ether and ester linkages between the aromatic rings of the main chain is an effective way to make polymers more tractable . These modifications lower glass transition temperature ( T g ) by increasing the molecular mobility with lower energy of internal rotation and consequently they provide enhanced solubility and processability . Another problem which hinders the development of PIs is dianhydrides, as the key components in the synthesis of PIs.…”