Synthesis and spectral, thermal, and photocrosslinking studies of poly(benzylidene phosphoramide ester)s

Abstract

A new class of poly ( benzylidene phosphoramide ester ) s containing a photoreactive benzylidene chromophore in the main chain were synthesized from bis(4-hydroxy-3-methoxy benzylidene)acetone with various substituted N-aryl phosphoramidic dichlorides by an interfacial polycondensation technique. The synthesized polymers were characterized by inherent viscosity, IR, and 1 H-, 13 C-, and 31 P-NMR spectroscopy. The molecular weights of these polymers were determined by gel permeation chromatography. These polymers were studied for their thermal stability and photochemical properties. Thermal properties were evaluated by thermogravimetric analysis and differential scanning calorimetry. It was found that halogen-containing polymers show a higher thermal stability than that of nonhalogenated polymers. The photocrosslinking property of these polymers was studied by ultraviolet spectroscopy. The photoreactive benzylidene chromophore in the main chain dimerizes via 2p / 2p cycloaddition reaction to form a cyclobutane derivative and leads to crosslinking.

Synthesis, spectral, and thermal characterization of photosensitive poly(ether–ester)s containing α,β‐unsaturated ketone moieties in the main chain derived from 2,6‐bis[4‐(3‐hydroxypropyloxy)‐3‐methoxybenzylidene]cyclohexanone

“…There has been much research on the synthesis of thermotropic polyesters1–3 and on a wide variety of systems, each with unique thermal and physical properties. Thermotropic polyesters with photosensitive groups find wide applications in photoresists to make integrated circuits, printing plates, photocurable coatings, photorecorders photoconductors, energy‐exchange materials, photosensitizers for organic synthesis, and liquid‐crystal displays 4. Photosensitivity, solubility, and thermal stability are the prime requirements for the use of these polymers in this field 5.…”

“…Thermotropic polyesters with photosensitive groups find wide applications in photoresists to make integrated circuits, printing plates, photocurable coatings, photorecorders photoconductors, energyexchange materials, photosensitizers for organic synthesis, and liquid-crystal displays. 4 Photosensitivity, solubility, and thermal stability are the prime requirements for the use of these polymers in this field. 5 Among them, some aliphatic and wholly aromatic thermotropic polyesters generally have high crystalto-isotropic transitions [melting temperatures (T m 's)]…”

Spectral, thermal, and photoreactivity studies on epoxy resin containing benzylidene units in the main chain

“…1 H NMR (DMSO‐d 6 ): 6.7 ppm (m, 6H, aromatic), 3.7 ppm (s, 6H, OCH 3 ), 9.6 ppm (s, 2H, OH), 7.2–7.7 ppm (d, 4H, CHCH). UV–vis λ max (C 2 H 5 OH): 353 nm (CC) 12…”

Synthesis and properties of phosphorus-containing polyesters derived from 2-(6-oxido-6H-dibenz?c,e??1,2?oxaphosphorin-6-yl)-1,4- hydroxyethoxy phenylene

“…Phosphorus-containing polymers are well recognized for their flame-retardant properties, and they are increasingly gaining popularity over their halogen counterparts, as they generally give off nontoxic combustion products. Some authors [1][2][3][4][5][6][7][8][9] have developed many flame-retardant phosphorus-containing polymers that exhibit excellent flame-retarding property with the LOI well above 40; 1-5 however, their degradation temperatures are low, ranging from 180 to 300°C. This may be due to the polymers having a OϭP-O bond in the main chain.…”