Synthesis, characterization, and curing of unsaturated polyamides derived from 2,6‐di(4‐carboxystyryl)pyridine and 2,6‐bis(4‐carboxybenzylidene) cyclohexanone

Abstract

SYNOPSISTwo new series of heat-curable polyamides were prepared utilizing the unsaturated dicarboxylic acids 2,6-di (4-carboxystyry1)pyridine (DCSP ) and 2,6-bis (4-carboxybenzylidene)cyclohexanone (BCBC) as starting materials. They were prepared from the condensation of 4-carboxybenzaldehyde with a half molar amount of 2,6-dimethylpyridine or cyclohexanone, respectively. The dicarboxylic acids reacted with various aromatic diamines, utilizing triphenyl phosphite and pyridine as condensing agents, to yield polyamides. In addition, two model diamides were prepared by condensing the dicarboxylic acids with aniline. Characterization of starting materials, polyamides, and model compounds was accomplished by IR and 'H-NMR spectroscopy. The curing behavior of polyamides was investigated by DTA. Upon heat-curing, the unsaturated polyamides were crosslinked through their olefinic bonds to afford insoluble, heat-resistant resins. The thermal stability of the resins was evaluated by TGA and isothermal gravimetric analysis (IGA) . The cured resins were stable up to 310-322°C in N2 or air and afforded anaerobic char yield of 57-69% a t 800°C.

Polyamides containing olefinic bonds

“…'H-NMR spectra were obtained using a Varian T-60A spectrometer at 60 MHz. Chemical shifts ( 6 ) are given in ppm with tetramethylsilane as an internal standard. The inherent viscosities of polyamides were determined for solutions of 0.5 g/ 100 mL in H p S 0 4 98% or N,N-dimethylformamide (DMF) at 30°C using an Ubbelohde suspended level viscometer.…”

New Fluorescent Crosslinked Aromatic Polyamides Containing Thiopheneand Furane in Their Backbone

“…The cyano groups enable the synthesis of heat-resistant cross-linkable polymers with high thermal stability (up to 370 ºC). Others polymers that can be crosslinked are those containing vinyl bonds in the main chain 11,[15][16][17] . Polymers containing crosslinkable functional groups are interesting since they have practical applications in optoelectronics 18 .…”

Development of anticorrosive two pack polyurethane coatings based on modified fatty amide of Azadirachta indica Juss oil cured at room temperature – a sustainable resource

“…Piperazine is a cyclic compound containing N atom in its cyclic ring and which has widely been used as a condensing agent in the preparation of polyamides. 36,37 Corrosion of metal surfaces is now the major issue all over the globe; one of the challenges is how to eliminate or reduce the corrosion of metals. The nitrogen atom present in the piperazine molecule contains a lone pair of electrons, which introduces hydrophilicity in the coatings that can enhance adhesion of the coating against the hydrophilic substrates (metals) and can also be used as a corrosion inhibitor for iron and steel.…”