Synthesis of homologous monomers and polymers of carbazole, phenothiazine and dibenzazepine

Gipstein, Edward; Hewett, William A.; Need, Omar U.

doi:10.1002/pol.1970.150081121

Cited by 32 publications

(14 citation statements)

References 8 publications

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“…Photocrosslinkable polymers are currently attracting significant attention in a wide area of applications such as photoresists to make integrated circuits, printing plates, printing inks, photocurable coatings and energy exchange systems, because of their excellent curing characteristics, thermal stability and chemical resistance 1–3. Photocrosslinkable liquid crystalline polymers find applications in anisotropic network systems like LC elastomers and LC thermosets, information storage devices, and thin films with a controlled orientation of functional groups, which are of interest in microelectronics and optoelectronics 4.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, thermal, and photocrosslinking studies of thermotropic liquid crystalline poly(benzylidene‐ether)esters containing α,β‐unsaturated ketone moiety in the main chain

Muthusamy

Krishnasamy

Murugavel

2013

J. Polym. Sci. A Polym. Chem.

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A series of poly(benzylidene-ether)esters containing a photoreactive benzylidene chromophore in the main chain were synthesized from 2,6-bis(4-hydroxy-3-methoxybenzylidene)cyclohexanone (BHMBCH) with various aliphatic and aromatic diacid chlorides by an interfacial polycondensation technique. The intrinsic viscosity of the synthesized homo and copolymers determined by Ubbelohde viscometer was found to be 0.12 to 0.17 dL/g. The molecular structure of the monomer and polymers was confirmed by FT-IR, 1 H NMR, and 13 C NMR spectral analyses. These polymers were studied for their thermal stability and photochemical properties. Thermal properties were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It was found that the polymers were stable up to 280 C and start degrading thereafter. Increase in acid methylene spacer length decreased the thermal stability. The self-extinguishing property of the synthe-sized polymers was studied by calculating the limiting oxygen index (LOI) value using a Van Krevelen's equation. The influence of the length of methylene spacer on phase transition was investigated using DSC and odd-even effect has been observed. Hot-stage optical polarizing microscopic (HOPM) study showed that most of the polymers exhibited birefringence and opalescence properties. The photolysis of liquid crystalline poly(benzylidene-ether)esters revealed that a,b-unsaturated ketone moiety in the main chain dimerises through 2p þ 2p cycloaddition reaction to form a cyclobutane derivative and leads to crosslinking.

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Section: Introductionmentioning

confidence: 99%

Synthesis, thermal, and photocrosslinking studies of thermotropic liquid crystalline poly(benzylidene‐ether)esters containing α,β‐unsaturated ketone moiety in the main chain

Muthusamy

Krishnasamy

Murugavel

2013

J. Polym. Sci. A Polym. Chem.

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“…4 VMPT was isolated by column chromatography on silica and then purified by recrystallization from chloroform-methanol. Soft pale yellow needles were obtained (24 % yield).…”

Section: Methodsmentioning

confidence: 99%

Photoresponsive Polymers. Photostimulated Viscosity Change of Poly(3-vinyl-10-methylphenothiazine) in 1,2-Dichloroethane in the Presence of Carbon Tetrachloride

Kungwatchakun

Hayashi

Irie

1988

Polym J

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ABSTRACT:The solution viscosity of poly(3-vinyl-10-methylphenothiazine) in 1,2-dichloroethane was found to decrease by as much as 50% on exposure to u1traviolet light (J > 290 nm) in the presence of carbon tetrachloride. The reduced viscosity again returned to the initial value by the addition of reductants, such as sodium dithionite. Absorption and ESR measurements of the solution suggested the formation of radical cations of pendant methylphenothiazine (MPT) groups by the interaction of the photoexcited MPT with carbon tetrachloride. Aggregation of ion-pairs of the cations and chloride ions due to dipole-dipole interactions is considered to be the driving force of the chain contraction. The addition of sodium dithionite reduces the radical cations to neutral forms and the chain again returns to the initial random conformation. KEY WORDS PhotoresponsivePolymers / Poly(3-vinyl-10-methylphenothiazine) / Radical Cation / Photoviscosity Effect / By incorporating a small amount of photoionizable chromophores into polymers, we have shown that the polymer chain conformation changes reversibly by photoirradiation.1 Poly(N,N-dimethylacrylamide) having pendant triphenylmethane leucohydroxide groups expands the conformation on exposure to ultraviolet light. The expanded conformation returns to the initial random conformation in the dark. The leucohydroxide chromophores dissociate into unstable ionpairs upon ultraviolet irradiation with production of colored triphenylmethyl cations along the polymer chain and in the dark the cations recombine with the counter ions.Phenothiazine and its derivatives are well known to undergo electrochemical oxidation to produce a radical cation in polar solvents. 2 The electrochemical properties of polymers with pendant MPT groups have been extensively studied by Morishima et al. 3 To produce stable ions, which do not disappear in the dark, in pendant groups upon photoirradiation, we prepared poly(3-vinyll O-methylphenothiazine) (1, polyVMPT), and examined the photoresponsive behavior.Photochemical oxidation of phenothiazine is reported to produce a neutral radical in ethanol by splitting off a hydrogen from nitrogen. 2 • When the mobile hydrogen is substituted by a methyl group, the MPT radical cation, instead of the neutral radical, is expected to be produced by photoirradiation in the presence of electron acceptors. Solvents were distilled twice before use. PolymerizationPolyVMPT was obtained by the radical polymerization of VMPT using AIBN as initiator in tetrahydrofuran (THF) at 60°C. The polymer was purified by reprecipitation with dry acetone from THF solution. The molecular-weight of the polymer was estimated to be 3.2 x 10 4 with a gel-permeation chromatography (Toyo-Soda HLC-802) by comparison with standard polystyrenes. MeasurementsPhotoirradiation was carried out with a Xe lamp (Ushio 15w). The light passed through a cut-off filter (Toshiba UV29, A>290nm) was used. y-Irradiation was carried out with 6°C o (dose rate 1 Mrad/h). Conformational change of the polymer was followe...

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“…These photosensitive polymers are widely used in photolithography, printing materials, photocurable coatings, photoconductors, liquid crystalline materials and non-linear optical material. [1][2][3][4][5][6] Photolithography technology has made significant contributions to the microelectronics device industry. [7] The photocrosslinking reactions of polymeric photoresists are the main tool for photolithography technology.…”

Section: Introductionmentioning

confidence: 99%

“…Polymers containing pendant chalcone group (―CO―CHCH―) undergo crosslinking by irradiation with UV light and are used as photoresists. These photosensitive polymers are widely used in photolithography, printing materials, photocurable coatings, photoconductors, liquid crystalline materials and non‐linear optical material . Photolithography technology has made significant contributions to the microelectronics device industry .…”

Section: Introductionmentioning

confidence: 99%

Studies on photocrosslinking and flame‐retardant properties of chalcone‐based polyacrylamides

Boopathy

Subramanian

2015

Polymers for Advanced Techs

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A photocrosslinkable polycyclic chalcone-based acrylamide has been synthesized by Claisen-Schmidt condensation reaction and then polymerized via free radical polymerization technique using azobisisobutyronitrile (AIBN) as an initiator. The resulting polymers have been characterized by FT-IR, 1 H-NMR and 13 C-NMR analytic techniques. The molecular weights of the polymers were determined by gel permeation chromatography. The thermal properties of synthesized polymers were characterized by TGA analysis, and the obtained results show good thermal and thermo-oxidative stability which is required for a negative photo resist. The high flame-retardant properties are calculated from limiting oxygen index (LOI) values and are found to be 36.9 and 32.0 for naphthyl and anthryl chalcone-based polymers, respectively. The experimentally determined LOI values of polymers (PMNPA and PAPA) are 34.3 and 30.2, respectively, and the values are closer to theoretically found LOI values. However, the cone calorimetry of flame-retardant PMNPA only showed a slight decrease in peak of heat release rate (PHRR) and total heat release (THR) compared to PAPA but the ignition time (TTI) of PMNPA is slightly higher than PAPA. The photocrosslinking properties of the polymers were investigated by UV spectroscopy technique and were found that with the increase in number of aromatic rings, the rate of crosslinking decreases. Thus polyacrylamides are useful in photolithography technology as well as flame-retardant property in electrical appliances.

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Synthesis of homologous monomers and polymers of carbazole, phenothiazine and dibenzazepine

Cited by 32 publications

References 8 publications

Synthesis, thermal, and photocrosslinking studies of thermotropic liquid crystalline poly(benzylidene‐ether)esters containing α,β‐unsaturated ketone moiety in the main chain

Synthesis, thermal, and photocrosslinking studies of thermotropic liquid crystalline poly(benzylidene‐ether)esters containing α,β‐unsaturated ketone moiety in the main chain

Photoresponsive Polymers. Photostimulated Viscosity Change of Poly(3-vinyl-10-methylphenothiazine) in 1,2-Dichloroethane in the Presence of Carbon Tetrachloride

Studies on photocrosslinking and flame‐retardant properties of chalcone‐based polyacrylamides

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