Alternating π‐conjugated copolymer of dithiafulvene with 2,2′‐bipyridyl units

A π‐conjugated polymer containing a dithiafulvene unit and a bipyridyl unit was prepared by cycloaddition polymerization of aldothioketene derived from 5,5′‐diethynyl‐2,2′‐bipyridine. Ultraviolet–visible (UV–vis) absorption spectra showed that the π‐conjugation system of the polymer expanded more effectively than that of a benzene analogue of poly(dithiafulvene) obtained from 1,4‐diethynylbenzene. Cyclic voltammetry measurements indicated that the dithiafulvene–bipyridyl polymer was a weaker electron‐donor polymer than the benzene analogue. These results supported the idea that the incorporation of the electron‐accepting bipyridyl moiety into conjugated poly(dithiafulvene) induced an intramolecular charge‐transfer (CT) effect between the units. Treatment of the dithiafulvene–bipyridyl polymer with bis(2,2′‐bipyridyl)dichlororuthenium (II) [Ru(bpy)₂Cl₂] afforded a ruthenium–polymer complex. A cyclic voltammogram of the complex showed broad redox peaks, which indicated electronic interaction between the dithiafulvene and tris(bipyridyl) ruthenium complex. The dithiafulvene–bipyridyl polymer formed CT complexes with 7,7,8,8‐tetracycanoquinodimethane (TCNQ) in dimethyl sulfoxide. The UV–vis absorption indicated that the resulting CT complex contained anion radical of TCNQ and partially charge‐transferred TCNQ. The polymer showed an unusually high electrical conductivity of 3.1 × 10^?4 S/cm in its nondoped state due to the effective donor–acceptor interaction between the bipyridine unit and the dithiafulvene unit. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4083–4090, 2001     

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

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, ¹H NMR, and ¹³C 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 synthesized 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 α,β‐unsaturated ketone moiety in the main chain dimerises through 2π + 2π cycloaddition reaction to form a cyclobutane derivative and leads to crosslinking. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Synthesis of π‐conjugated poly(dithiafulvene) by cycloaddition polymerization of aldothioketene from a bis(1,2,3‐thiadiazole) monomer

A π‐conjugated poly(dithiafulvene) ( 2 ) was obtained by the cycloaddition polymerization of aldothioketene with its alkynethiol tautomer derived from 1,4‐bis(1,2,3‐thiadiazolyl‐4‐yl)benzene ( 1 ) in a 94% yield. To a mixure of 1 and dimethyl sulfoxide (DMSO)/ethanol (5/1, v/v), KOH was added. After stirring the mixture overnight, piperidine was added to quench the terminal thioketenes. The reaction mixture was then poured into water to obtain the product. The cycloaddition polymerization of aldothioketene derived from 1 with its alkynethiol tautomer was studied under various conditions in several solvent systems. The structure of the polymer was supported by the ¹H NMR and ¹³C NMR spectra. The number‐average degree of polymerization (DP) of 2 was 8, estimated from the ¹H NMR analysis. Optical properties and electrochemical analysis of 2 were also studied. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5872–5876, 2004     

Synthesis and characterization of aromatic cyclolinear phosphazene polyetherketones containing bis‐Spiro‐substituted cyclotriphosphazene unit

A novel monomer, 2,2‐bis‐(4′‐fluorobenzoylphenoxy)‐4,4,6,6‐bis[spiro‐(2′,2″‐dioxy‐1′, 1′‐biphenylyl)] cyclotriphosphazene, was synthesized and polymerized with 4,4′‐difluorobenzophenone as a comonomer and 4,4′‐isopropylidenediphenol or 4,4′‐(hexafluoroisopropylidene) diphenol in N,N‐dimethylacetamide at 162 °C for 4 h to give two series of aromatic cyclolinear phosphazene polyetherketones containing bis‐spiro‐substituted cyclotriphosphazene groups. The structure of the monomer was confirmed by ¹H, ¹³C, and ³¹P NMR. The effect of the incorporation of the bis‐spiro‐substituted cyclotriphosphazene group on the thermal properties of these polymers was investigated by DSC and thermogravimetric analysis. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2993–2997, 2001     

Hydrogen‐bonded thermotropic liquid‐crystalline polyester–amides from bis(hydroxy alkamido)aranes: Synthesis and properties

Hydrogen‐bonded aromatic–aliphatic polyester–amides (PEAs) were prepared by solution/melt polycondensation of aromatic–aliphatic amidodiols 1,4‐bis(4‐hydroxybutyramide)benzene (BHBB), 1,4‐bis(5‐hydroxy pentamide)benzene, 1,4‐bis(6‐hydroxyhexamide)benzene, 1,4‐bis(4‐hydroxybutyramidexylene), 1,4‐bis(5‐hydroxypentamidexylene, 1,4‐bis(4‐hydroxybutyramide)benzene, and 1,4‐bis(6‐hydroxyhexamidexylene) with terephthaloyl chloride/dimethyl terephthalate. Aromatic–aliphatic amido diols were prepared by the aminolysis of γ‐butyrolactone, δ‐valerolactone, and ?‐caprolactone with aromatic diamines such as paraphenylene diamine and paraxylene diamine. The monomers and polymers were characterized by chemical analysis (hydroxyl value and elemental analysis), Fourier transform infrared spectroscopy, ¹H NMR, and ¹³C NMR. The thermal‐ and phase‐transition behaviors of the polymers were investigated by differential scanning calorimetry in combination with hot‐stage optical microscopy. Crystallinity of polymers was examined with wide‐angle X‐ray diffraction. The polymers exhibited liquid crystallinity with layered structures formed by self‐organization of the hetero intermolecular hydrogen‐bonded networks indicating smectic phases except for PEAs prepared from BHBB. The hydrogen atom of the phenyl‐substituent group forces the neighboring carbonyl groups out of plane of the rings preventing formation of layered structures in the case of BHBB. The PEAs retained intermolecular hydrogen bonding even in the mesomorphic state, and variations in the hydrogen‐bonded lamellae/micelles might be responsible for the variations from one smectic to another texture. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 335–346, 2003     

Poly‐Schiff bases. V. Synthesis and characterization of novel soluble fluorine‐containing polyether azomethines

A new dialdehyde monomer, 4,4′‐(hexafluoroisopropylidine) bis(p‐phenoxy) benzaldehyde, was prepared; it led to a number of novel poly‐Schiff bases in reactions with different diamines, such as 4,4′‐diaminidiphenyl ether, 4,4′‐(isopropylidine) bis(p‐phenoxy) dianiline, 4,4′‐(hexafluoroisopropylidine) bis(p‐phenoxy) dianiline, and benzidine. The polymers were characterized with viscosity measurements, nitrogen analyses, and IR and ¹H NMR spectroscopy. These poly‐Schiff bases showed good thermal stability up to 491 °C for 10% weight loss in thermogravimetric analysis under air and high glass‐transition temperatures up to 215 °C in differential scanning calorimetry. These polymers were soluble in a wide range of organic solvents, such as CHCl₃, dimethylformamide (DMF), dimethyl sulfoxide, and 1‐methyl‐2‐pyrrolidon (NMP), and were insoluble in toluene and acetone. Thin films of these polymers cast from DMF exhibited tensile strengths up to 38 MPa. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 383–388, 2001     

Synthesis,characterization, and degradation of poly(anhydride‐co‐amide)s and their blends with polylactide

In attempt to improve the properties of polyanhydrides based on aliphatic anhydrides, we synthesized novel polyanhydrides containing amide groups in the main chains. In this work, N,N′‐bis(L ‐alanine)‐sebacoylamide (BSAM) was prepared from natural amino acid and sebacic acid (SA) and characterized by IR and ¹H NMR. In addition, polymers of PBSAM, P[1,6‐bis(P‐carboxyphenoxy) hexane (CPH)‐BSAM], and P(CPH‐SA), blends of P(CPH‐SA)/polylactide (PLA), P(CPH‐BSAM)/PLA were also prepared and characterized by IR, gel permeation chromatography, and differential scanning calorimetry. The hydrolytic degradation of polyanhydrides and their blends with PLA (number‐average molecular weight = 2.90 × 10⁵) was evaluated in 0.1 M phosphate buffer pH 7.4 at 37 °C. The results indicate that the existence of amide, aromatic, and ester bonds in the main chain of polymers slows down the degradation rate, and the tendency becomes clearer with the increasing amount of them, and the copolymers and their blends with PLA possess excellent physical and mechanical properties. These can make them more widely used in drug delivery and nerve regeneration. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4311–4317, 2004     

Pt‐catalyzed chemical modification of α,ω‐bis(hydrido)polydimethylsiloxanes and copoly(methylhydridosiloxane/dimethylsiloxane) with vinylheptaphenylcyclotetrasiloxane

Pt‐catalyzed hydrosilylation between vinylheptaphenylcyclotetrasiloxane and a series of α,ω‐bis(hydrido)polydimethylsiloxanes and copoly(methylhydridosiloxane/dimethylsiloxane) was used to prepare chemically modified materials. These modified polymers were characterized by IR, UV, and ¹H, ¹³C, and ²⁹Si NMR spectroscopy and gel permeation chromatography (GPC). The molecular weights, determined by GPC, UV, and NMR end‐group analysis, showed the anticipated increases. The thermal properties of the polymers were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The crystallinity, determined by DSC, was either reduced or completely eliminated for the modified polymers. The thermal stabilities, measured in both air and nitrogen by TGA, were slightly higher than the thermal stability of α,ω‐bis(trimethylsiloxy)polydimethylsiloxane. Significantly increased bulk viscosities were observed for all the modified polymers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3007‐3017, 2005     

Regioselective and stereoselective alternating copolymerization of carbon monoxide with functional olefins

Enantioselective, alternating copolymerizations of carbon monoxide with ω‐undecylenic acid, ethyl acrylate, and butyl acrylate were carried out for the first time with a palladium catalyst modified by 1,4:3,6‐dianhydro‐2,5‐dideoxy‐2,5‐bis(diphenylphosphino)‐L ‐iditol. Optical rotation, elemental analysis, and ¹H NMR,¹³C NMR, and IR spectra showed that the copolymers were optically active, isotactic, alternating poly(1,4‐ketone) or poly(spiroketal) structures. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2027–2036, 2001     

Oxidation polymerization of a charge‐transfer complex of 2,6‐bis(2‐thienyl)‐1,4‐dithiafulvene with 7,7,8,8‐tetracyanoquinodimethane

A π‐conjugated poly(α‐dithienylen‐dithiafulvene) ( 2 ) was obtained by the oxidation polymerization of 2,6‐bis(2‐thienyl)‐1,4‐dithiafulvene ( 1 ) as a dithiafulvene monomer derived from 4‐(2‐thienyl)‐1,2,3‐thiadiazole. When a solution of 1 in CHCl₃ was added to a stirred solution of FeCl₃ in CHCl₃, only the low‐molecular‐weight product 2 was obtained. The mixture was stirred for 15 h with an N₂ flow. The polymerization at higher temperatures resulted in polymers with large insoluble fractions. A higher molecular weight polymer was obtained by the oxidation polymerization of a charge‐transfer complex of 1 with 7,7,8,8‐tetracyanoquinodimethane (compound 3 ). In contrast to 2 , polymer 4 was readily soluble in dimethyl sulfoxide, dimethylformamide, and acetone and partially soluble in tetrahydrofuran and methanol and had a larger molecular weight (peak top molecular weight = 37,000). The conductivity of polymer 4 was 3 orders of magnitude larger than that of polymer 2 . © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6592–6598, 2005     

Novel thermotropic liquid crystalline‐cum‐photocrosslinkable polyvanillylidene alkyl/arylphosphate esters

A new class of linear unsaturated polyphosphate esters based on divanillylidene cyclohexanone possessing liquid crystalline‐cum‐photocrosslinkable properties have been synthesized from 2,6‐bis[n‐hydroxyalkyloxy(vanillylidene)]cyclohexanone [n = 6,8,10] with various alkyl/aryl phosphorodichloridates in chloroform at ambient temperature. The resultant polymers were characterized by intrinsic viscosity, FT‐IR, ¹H, ¹³C, and ³¹P‐NMR spectroscopy. All the polymers showed anisotropic behavior under hot stage optical polarized microscope (HOPM). The liquid crystalline textures of the polymers became more transparent with increasing spacer length. The thermal behavior of the polymers was studied by thermogravimetric analysis and differential scanning calorimetry. The T_g, T_m, and T_i of the polymers decreased with increasing flexible methylene chain. The photocrosslinking property of the polymer was investigated by UV light/UV spectroscopy; the crosslinking proceeds via 2π‐2π cycloaddition reactions of the divanillylidene exocyclic double bond of the polymer backbone. The pendant alkyloxy containing polymers show faster crosslinking than the pendant phenyloxy containing polymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5215–5226, 2004     

Cobalt(III)-catalyzed cycloaddition polymerization of diynes with nitriles: Synthesis of polymers containing pyridine moieties in the main chain

The synthesis of pyridine-containing polymers was carried out by the cycloaddition of diynes with nitriles in the presence of organocobalt complexes as catalysts. As a model experiment, the pyridine-formation reaction of monofunctional acetylenes with nitriles was reexamined in detail in the presence of organocobalt catalysts, from which the combination of terminal aliphatic acetylenes and aromatic nitriles was proved to be suitable for the specific pyridine-formation process. On the basis of this result, the polymerization of terminal aliphatic diynes with aromatic nitriles was carried out in the presence of the cobalt catalyst (10 mol %) to give polymers containing substituted pyridine moieties in the main chain in high yields. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1979–1986, 1999     

Hyperbranched Poly(aryleneethynylene)s: Synthesis,Thermal Stability and Optical Properties

Summary: Alkyne copolycyclomerizations of aromatic diynes 2,7‐bis(4‐ethynylphenylethynyl)‐9,9‐dihexylfluorene ( I ) and 1,4‐bis(4‐ethynylphenylethynyl)benzene ( II ) with an aliphatic monoyne 1‐dodecyne ( A ) were effected by CpCo(CO)₂ hv in THF, producing hyperbranched poly(aryleneethynylene)s ( 1 and 2 ) of high molecular weights ( up to 4.4 × 10⁴ Da) in high isolation yields (up to 97%). The polymers possessed outstanding thermal stability and emitted strong deep blue light of ≈400 nm when their solutions were photoexcited. The polymers effectively limited the light of a 532 nm laser, with the performance of 2 being better than that of C₆₀, a well‐known optical limiter, under similar linear transmittance.

The structure of hyperbranched poly(aryleneethynylene).     

Synthesis and properties of novel phosphorus‐containing thermotropic liquid crystalline copoly(ester imide)s

A series of novel phosphorus‐containing polyesterimides were prepared from diols—a mixture of a new aromatic phosphorus‐containing bisphenol, namely 1,4‐bis[N‐(4‐hydroxyphenyl)phthalimidyl‐5‐carboxylate]‐2‐(6‐oxido‐6H‐dibenz<c,e><1,2>oxaphosphorin‐6‐yl)‐naphtalene, with aliphatic diols such as 1,3‐propanediol, 1,4‐butanediol, 1,5‐pentanediol, 1,6‐hexanediol, and 1,12‐dodecanediol—and an aromatic diacid chloride containing two preformed ester groups, namely terephthaloyl‐bis‐(4‐oxibenzoyl‐chloride), via high‐temperature polycondensation in o‐dichlorobenzene. The structures of monomers and polymers were verified by means of Fourier transform infrared (FTIR) spectroscopy and ¹H NMR spectroscopy. The molar ratio of aromatic bisphenol to aliphatic diol was varied to generate a series of copolyesterimides with tailored physicochemical properties, structure–properties relationships being established. The effect of the phosphorus content on the thermal properties and the flame retardancy was evaluated by means of thermogravimetric analysis (TGA), TGA–FTIR, and scanning electron microscopy. The polymers were stable up to 340 °C showing a 5% weight loss in the range of 340–395 °C and a 10% weight loss in the range of 370–415 °C. The char yields at 700 °C were in the range of 13.6–38% increasing with the content of phosphorus‐containing bisphenol. The effect of the aliphatic content on the liquid crystalline behavior was investigated by polarized light microscopy, differential scanning calorimetry, and X‐ray diffraction. The transition temperatures from crystal to liquid crystalline melt were in the range of 209–308 °C. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Synthesis and hydrolytic degradation of stereoregular aromatic poly(ester amide)s derived from D‐xylose

Stereoregular poly(ester amide)s (PEAs) were prepared by the polycondensation method using naturally occurring D ‐xylose and aromatic diacids as the starting materials. The polymers were characterized by elemental analysis, GPC, IR, and ¹H‐ and ¹³C NMR spectroscopies. Thermal and X‐ray diffraction studies revealed them to be mainly amorphous. The polymers are hydrophilic and their degradation studies were carried out at 37 and 80 °C in buffered salt solution at pH 8. The degradation study was monitored by mass loss, GPC, IR, and NMR spectroscopies. The hydrolytic degradation of these PEAs occurred rapidly by hydrolysis of the ester functions to a final compound, which maintained the amide functions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Preparation of linear and hyperbranched fluorinated poly(aryl ether‐thioether) through para‐fluoro‐thiol click reaction

The para‐fluoro‐thiol “click” reaction (PFTCR) was utilized to prepare linear and hyperbranched fluorinated poly (aryl ether‐thioether). For this purpose, 1,2‐bis(perfluorophenoxy)ethane was prepared and reacted with 1,6‐hexandithiol and trimethylolpropane tris(3‐mercaptopropionate), respectively. While hyperbranched polymers were prepared using 0.5 M concentrations of starting materials at room temperature, the linear polymer syntheses were performed at different reaction temperatures and concentrations. The resulting polymers were mainly characterized by NMR measurements and a very distinct fluorine signals regarding meta‐ and ortho‐ positions in the ¹⁹F NMR were found for both polymer topologies. In addition to NMR analyses, both linear and hyperbranched polymers were further characterized by using Fourier transform infrared spectroscopy (FT‐IR), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1853–1859     

Optical and electronic properties of fluorene‐based copolymers and their sensory applications

A series of novel, fluorene‐based conjugated copolymers, poly[(9,9‐bis{propenyl}‐9H‐fluorene)‐co‐(9,9‐dihexyl‐9H‐fluorene)] ( P1 ), poly[(9,9‐bis{carboxymethylsulfonyl‐propyl}fluorenyl‐2,7‐diyl)‐co‐(9,9‐dihexyl‐9H‐fluorene)] ( P2 ) and poly[(9,9‐dihexylfluorene)‐co‐alt‐(9,9‐bis‐(6‐azidohexyl)fluorene)] ( P3 ), are synthesized by Suzuki coupling reactions and their electrochemical properties, in the form of films, are investigated using cyclic voltammetry. The results reveal that the polymer films exhibit electrochromic properties with a pseudo‐reversible redox behavior; transparent in the neutral state and dark violet in the oxidized state. Among the three polymers, P2 possesses the shortest response time and the highest coloration efficiency value. These polymers emit blue light with a band gap value of around 2.9 eV and have high fluorescent quantum yields. Their metal ion sensory abilities are also investigated by titrating them with a number of different transition metal ions; all of these polymers exhibit a higher selectivity toward Fe³⁺ ions than the other ions tested with Stern–Volmer constants of 4.41 × 10⁶M^?1, 3.28 × 10⁷M^?1, 1.25 × 10⁶M^?1, and 6.56 × 10⁶M^?1 for P1 , P2 , water soluble version of P2 ( P2S ) and P3 , respectively. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Preparation and properties of novel polyimides derived from 4‐aryl‐2,6 bis(4‐amino phenyl)pyridine

To prepare novel polyimides with enhanced thermal stability and high solubility in common organic solvents, diamine monomers, 4‐aryl‐2,6 bis‐(4‐amino phenyl)pyridine, were introduced. The diamines were reacted with three different conventional aromatic dianhydrides including pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, and hexafluoroisopropylidene‐2,2‐bis(phthalic‐dianhydride) (6FDA) in dimethylacetamide solvent to obtain the corresponding polyimides via the polyamic acid precursors and chemical imidization. The monomers and polymers were characterized by Fourier transform infrared spectroscopy, ¹H NMR, mass spectroscopy, and elemental analysis; and the best condition of polymerization and imidization were obtained via the study of model compound. The polyimides showed little or no weight loss by thermogravimetric analysis up to 500 °C, and those derived from 6FDA exhibited good solubility in various polar solvents. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3826–3831, 2001     

Iron(II)‐ and Cobalt(II) Complexes with Tridentate Bis(imino)pyridine Nitrogen Ligands Bearing Chiral Bulky Aliphatic and Aromatic Substituents: Crystal Structure of [CoCl2{2, 6‐bis[R‐(+)‐(bornylimino)methyl]pyridine}]

Iron(II) and cobalt(II) complexes ( 7 ‐ 15 ) based on new aldimine 2, 6‐bis[(imino)methyl]pyridine ( 1 , 2 , 4 , 6 ) and ketimine (2, 6‐bis[(imino)ethyl]pyridine ( 3 , 5 ) ligands with bulky chiral aliphatic or aromatic terminal groups have been prepared and characterized by ¹H NMR, ¹³C NMR, IR‐, mass spectroscopy (EI), and elemental analysis. The complex [CoCl₂(BBoMP)]·¹/₂ CHCl₃ ( 13 ) (BBoMP: 2, 6‐bis{(R‐(+)‐(bornylimino)‐methyl}pyridine) crystallizes in monoclinic space group P2₁ with cell dimensions: a = 7.6603(11) Å, b = 28.3153(14) Å, c = 13.537(2) Å, V = 2908.1(6) ų, Z = 4. The coordination sphere around Co is distorted trigonal bipyramidal.     

Synthesis and crosslinking of vinyl‐terminated biphenyl and naphthalene liquid‐crystalline poly(epichlorohydrin) derivatives: Effect of nonmesogenic nonvinylic units on the mesogenic properties

Two series of vinyl‐terminated side‐chain liquid‐crystalline polyethers containing ethylene oxide or glycidyl aromatic carboxylates as spacers were synthesized. The mesogenic cores were 4,4′‐biphenyl or 2,6‐naphthalene moieties. The polymers were synthesized by chemically modifying poly(epichlorohydrin) or poly(epichlorohydrin)‐poly(ethylene oxide) with the corresponding mesogenic carboxylic acids or with mixtures of these acids and the nonmesogenic non‐crosslinkable analogous 4‐biphenyl‐ and 2‐naphthalenecarboxylic acids. In most cases the degree of modification achieved was higher than 90%. The polymers were characterized by chlorine analysis, IR, and ¹H and ¹³C NMR spectroscopies; viscosimetry; size exclusion chromatography; multi‐angle laser light scattering; and thermogravimetric analysis. The liquid‐crystal behavior, shown by most polymers, was examined by differential scanning calorimetry, polarized optical microscopy (POM), and X‐ray diffraction on mechanically oriented samples. The crosslinking of most polymers was done by peroxide‐type initiators that led to liquid‐crystal thermosets or elastomers. The freezing of the mesophase organization on the crosslinked materials was confirmed by POM and X‐ray diffraction. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3893–3908, 2002