RESEARCH OF THERMAL AND THERMOMECHANICAL PROPERTIES OF COPOLYMERS BASED ON PYROMELLITE DIANHYDRIDE, 4,4'-DIAMINODIPHENYLOXIDE AND [2-(AMINOMETHYL)BICYCLO[2.2.1]HEPT-3-YL]ANILINES

The thermal and thermomechanical properties of copolyimides based on pyromellitic dianhydride, 4,4'-diaminodiphenyloxide and [2-(aminomethyl)bicyclo [2.2.1]hept-3-yl]anilines in an inert medium have been studied for the first time. It is shown that the introduction into the structure of aromatic polyimides up to 20 mol %. asymmetric vicinally substituted bicyclic diamines allows to obtain materials with increased hydrolytic stability in comparison with fully aromatic polyimides while maintaining a high level of thermomechanical characteristics.

Preparation and Carbonization of Glucose and Pyromellitic Dianhydride Crosslinked Polymers

In this work, four types of nanosponges were prepared from pyromellitic dianhydride (PMDA) and D-glucose (GLU) with different molar ratios (1.5:1, 2:1, 2.5:1 and 3:1). The obtained PMDA/GLU nanosponges were then pyrolyzed at 800 °C for 30 min under N2 gas flow. The prepared polymeric nanosponges were investigated by FTIR spectroscopy, elemental and thermogravimetric analyses to unravel the role played by the different molar ratio of the precursors in the formation of the polymer. The pyrolyzed nanosponges were investigated by means of porosity measurements, X-ray diffraction analysis, Raman spectroscopy and high-resolution transmission electron microscopy. Notably, no significant correlation of the amounts of used precursors with the porous texture and structure was evidenced. The results corroborate that PMDA and GLU can be easily combined to prepare nanosponges and that the carbon materials produced by their pyrolysis can be associated with glassy carbons with a microporous texture and relatively high surface area. Such hard carbons can be easily obtained and shrewdly used to segregate relatively small molecules and organic contaminants; in this study methylene blue adsorption was investigated.

Sulfonated Pyromellitic Dianhydride-functionalized MCM-41: A Multifunctional Hybrid Catalyst for Melting-assisted Solvent-free Synthesis of Bioactive 3,4-dihydropyrimidin-2-(1H)-ones

This study introduces a practical approach to fabricate a novel hybrid catalyst of namely sulfonated pyromellitic dianhydride-aminopropyl silane-functionalized MCM-41 (MCM-41-APS-PMDA-SO3H). Various microscopic, spectroscopic methods and techniques such as FTIR, TGA, XRD, FESEM, and EDX were used to confirm its structural characteristics. The efficiency of the new MCM-41-APS-PMDA-SO3H organosilica nanomaterials, as a heterogenous nanocatalyst, was evaluated in promoting the synthesis of biologically active 3,4-dihydropyrimidin-2-(1H)-one derivatives under solvent-free conditions. It is not only a nano-porous material for enriching reactants with high surface area provided, but also possesses great acidic sites to activate carbonyl groups. Furthermore, favored reusability of the new introduced hybrid organosilica with negligible loss of its activity, easy and quick isolation of the products are the main advantages of this procedure.

One-pot Cascade Polycondensation and Passerini Three-Component Reactions for the Synthesis of Functional Polyesters

Herein, we present a one-pot cascade reaction for the synthesis and simultaneous modification of polyesters. Pyromellitic dianhydride (PMDA) was reacted with a variety of diols to produce polyesters, meanwhile, the...