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Novel, linear, high-molecular-weight single-strand heteroaromatic polymers and copolymers containing 9H-xanthene moieties in the backbone were synthesized by metal-free superacid-catalyzed stoichiometric and nonstoichiometric step-growth polymerizations of carbonyl compounds bearing electron-withdrawing substituents with bisphenols. The electrophilic aromatic substitution reactions of ketones with phenol fragments occur exclusively in ortho-positions to the hydroxy phenol group and followed by highly efficient cyclodehydration reaction of hydroxyl-containing intermediates to give corresponding substituted 9H-xanthene-2,7-diyl polymers. The polymerizations were performed at room temperature in the Bronsted superacid trifluoromethanesulfonic acid (CF3SO3H, TFSA) and in a mixture of TFSA with methylene chloride and nitrobenzene.

Synthesis of processable, aromatic pyridine-containing polymers has always been a great challenge. Here, we report for the first time a robust, low-cost synthesis of well defined, high molecular weight, linear, wholly aromatic polymers with rigid ether-bond-free aryl backbones, where the proportion and position of pyridine moieties and spacer lengths between them in the macromolecules are fully controlled. The polymers, in nearly quantitative yields, were obtained by one-pot, room temperature, metal-free, non-stoichiometric superacid catalyzed step-polymerization of 4-acetylpyridine (and its mixtures with 2,2,2-trifluoroacetophenone) with multiring aromatic hydrocarbons: biphenyl, meta- and para-terphenyl, and para-quaterphenyl, in the mixture of trifluoromethanesulfonic acid with methylene chloride and trifluoroacetic acid. The polymers are highly soluble in most common solvents and form flexible and tough films with tensile strength in the range of 72–92 MPa. 1H and 13C NMR analyses of the synthesized polymers revealed high regio-selectivity of the polymer forming reaction affording linear structures with para-substitution in the phenylene fragments of the main chains. The molecular weights of the polymers ranged from 20 000 to 100 000 g mol−1, whereas the polydispersity is generally well below 2. The polymers exhibited also high thermostability with Tg > 400 °C, weight loss temperatures (N2, onset) ca. 485 °C, char yields of 70–75 at 800 °C and high chemical stability. Room temperature reactions of the polymers with methyl(trifluoromethylsulfonate) afford the N-methylated cationic polymers. Certain studies on the physical properties and gas separation of the polymers are highlighted.

Summary We used chemical modification to obtain new polymers that contain pyrrole units in the main chain, with electron-withdrawing groups acting as potential organic semiconductors, by means of chemical modification of the diacetylene-containing precursors. These were prepared by oxidative coupling of terminal diacetylenes or by superelectrophilic polycondensation of diphenoxydiacetylene with isatin. Diacetylenic fragments in the precursors reacted with aromatic amines that bore electron-withdrawing substituents in the presence of copper chloride, in order to yield the corresponding diphenyl-pyrrole polymers. These were then fully characterized by NMR, IR and thermal analysis. The molecular weights of the polymers were also determined by GPC. We used UV–vis spectroscopy to derive the optical band gap of the polymers. The band gap values of synthetized polymers can be modulated by modifying the position and type of substituent. Band gaps obtained in wafer form range from 1.35 to 2.8 eV; the range required for polymer semiconductors, if they are to be employed in optoelectronic devices.

Polymeric membranes are highly advantageous over their ceramic counterparts in terms of the simplicity of the manufacturing process, cost and scalability. Their main disadvantages are low stability at temperatures above 200 °C, and in organic solvents. We report for the first time porous polymeric membranes manufactured from poly(oxindolebiphenylylene) (POXI), a polymer with thermal stability as high as 500 °C in oxidative conditions. The membranes were prepared by solution casting and phase inversion by immersion in water. The asymmetric porous morphology was characterized by scanning electronic microscopy. The pristine membranes are stable in alcohols, acetone, acetonitrile and hexane, as well as in aqueous solutions with pH between 0 and 14. The membrane stability was extended for application in other organic solvents by crosslinking, using various dibromides, and the efficiency of the different crosslinkers was evaluated by thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). POXI crosslinked membranes are stable up to 329 °C in oxidative conditions and showed organic solvent resistance in polar aprotic solvents with 99% rejection of Red Direct 80 in DMF at 70 °C. With this development, the application of polymeric membranes could be extended to high temperature and harsh environments, fields currently dominated by ceramic membranes.

The synthesis and properties of novel aromatic poly- and co-polyisopthalamides bearing –OH, -tert-butyl (TERT) and 3,5-bis(trifluoromethyl) benzoyl (BTFB) groups are reported. All synthesized aramides are highly soluble in aprotic solvents, thermally stable up to 400 °C and present good film forming ability. The combination at random of -OH group with TERT or BTFB groups in copolymers CPA 1 and CPA 2 is highly effective for improving gas permeability ( P ) for all tested gases (CO 2 , O 2 , N 2 , CH 4 ) and selectivity (α) for CO 2 /CH 4 and CO 2 /N 2 . Copolymer CPA 2b containing OH and BTFB groups exhibited high gas permeability and good selectivity (P CO2 =60.17 and P CH4 =2.67, α=22.53) in comparison with analogous polyamides and some polyimides. These results are well correlated with both the increase in fractional free volume (FFV) and interchain d -spacing.

Novel fluorinated aromatic polymers were obtained by one-pot, metal-free, superacid-catalyzed step-polymerization of trifluoromethylalkyl 1(a-b) and trifluoromethylaryl (1c) ketones with p-quaterphenyl (A). The room temperature polymerizations performed in a mixture of trifluoromethanesulfonic acid (CF3SO3H, TFSA) with methylene chloride gave polymeric particles. Thermogravimetric analysis for the particles revealed insignificant weight loss below 500 °C confirming their polymeric nature. Studies of solid state NMR revealed the incorporation of p-quaterphenyl in the polymer chain. The regioselectivity of polymerizations involving p-quaterphenyl and fluoroketones has been confirmed by the preparation and NMR characterization of soluble copolymers of trifluoroacetophenone (1c) with p-terphenyl/quaterphenyl mixtures. Conformational rigidity and free volume calculations confirm polymers with medium hardness and with free volumes around 0.205–0.221 cm3/g. Scanning electron microscopy show rough surfaces with pore sizes around 20–50 nm. The H2, N2 and CO2 adsorption isotherms show that these polymers may possess intrinsic microporosity making them potential molecular sieves.

Three novel fluorinated polymers with ether-bond-free aryl backbones were obtained by one-pot, metal-free, room temperature superacid catalyzed non-stoichiometric step polymerization of 1,1,1-trifluoromethyl acetone with carbazole (CBZ), fluorene (FLN) and 9,9-dimethylfluorene (DFL). 1H and 13C NMR analyses of the polymers revealed their linear structure and high regioselectivity of the polymer forming reaction. The polymers also possess high thermostability with decomposition temperature up to 387 °C for CBZ and up to 530 °C for FLN and DFL as well as reasonable mechanical properties. The gas transport properties of six pure gases and binary gas mixture CO2/CH4 (10/90 mol%) are reported. These polymers present a good combination of permeability and selectivity up to 10 bar at 35 °C for CO2/CH4 mixed-gas feed. DFL exhibits the best pure-gas permeability and selectivity (PCO2 = 78.0, PH2 = 151.5, CO2/CH4 = 22.3 and H2/CH4 = 43.3) and mixed-gas permeability and selectivity CO2/CH4 (PCO2 = 71.3, CO2/CH4 = 23.7) at 35 °C and 2 bar with a slight decrease in selectivity at 10 bar. The highest permselectivity is obtained for FLN (CO2/CH4 = 36.7 and H2/CH4 = 88.4) with a separation performance close to the 2008 upper bound trade off.

A novel series of linear, high-molecular-weight polymers and copolymers were synthesized by one-pot, metal-free superacid-catalyzed polymerization of aliphatic 1,2-diketones (2,3-butanedione (1a), 2,3-hexadione (1b), 3,4-hexadione (1c), 2,3-butanedione monoxime (1d), pyruvic acid (1e), 1,4-dibromo-2,3-butanedione (1f), 2-bromopyruvic acid (1g), and methyl-3,3,3-trifluoropyruvate (1h) with linear, nonactivated, multiring aromatic hydrocarbons terphenyl (A), biphenyl (B), fluorene (C), and N-ethyl carbazole (D). Depending on the reaction system, the polymerizations were carried out as stoichiometric or non stoichiometric, with direct or inverse monomer addition. Copolymers were obtained by polymerization of 1,2-diketones with a mixture of aromatic hydrocarbons. In the course of the polymerization only one carbonyl group of a 1,2-diketone reacts to form C–C bonds with aromatic fragments while the other functional groups (including the second carbonyl group) are incorporated unchanged into polymer chain. The ...

This work presents the results of polymer membranes whose permeability and selectivity combination of properties can be defined through the chemical modification, in the solid state, of the repeating unit of a poly(oxindolebiphenylyene) that bears a −CH2OH group, PN–CH2OH. The chemical modifications are promoted by moderate thermal treatments (160–180 °C) and short times (

A novel series of linear, high-molecular-weight polymers and copolymers was synthesized by one-pot, metal-free superacid-catalyzed reaction of trifluoromethylalkyl (1a-1c) and trifluoromethylaryl (1d-1h) ketones with the linear, nonactivated, multiring aromatic hydrocarbons biphenyl (A), p-terphenyl (B), and p-quaterphenyl (C).The polymerizations were performed at room temperature in the Brønsted superacid trifluoromethanesulfonic acid (CF3SO3H, TFSA) and in a mixture of TFSA with methylene chloride. Polymerizations of trifluoromethyl ketones (1c, 1f-1h) bearing functional groups gave polymers with reactive lateral groups such as bromomethyl, 4-(N,N-dimethylamino)phenyl-, 3-sulfophenyl-, and 2,3,4,5,6-pentafluorophenyl. The polymers obtained were soluble in most common organic solvents and flexible transparent films could be cast from the solutions. 1H and 13C NMR analyses of the polymers synthesized revealed their linear structure with para-substitution in the phenylene fragments of the main chain. The molecular weights (Mw) of the polymers based on trifluoromethylalkyl ketones and aromatic are very high and reach 1 000 000, while the molecular weights of the polymers based on trifluoromethylaryl ketones and aromatic ranged from 30 000 to 300 000 g/mol. The polydispersity of the polymers is generally less than 2. The polymers also possess high thermostability. Mechanistic aspects of polymerization mechanism have been discussed, and a new approach for monomer design has been proposed. © 2013 American Chemical Society., Financial support from CONACYT Mexico (Grant 151842) and from DGAPA-UNAM (PAPIIT IN 104211)

A reliable and practical approach is offered for the two critical fundamental challenges that remain in step-growth polymerization: synthesis of narrow polydispersity and ultrahigh molecular weight polymers. The polymers are obtained by superacid catalyzed polyhydroxyalkylation involving two consecutive steps – slow and fast. Polymer syntheses with decrease in reactivity of intermediates lead to narrow polydispersity polymers, while nonstoichiometric reactions result in polymers of high and ultrahigh molecular weight. Linear aromatic polymers with ultra high molecular weight Mn > 1 000 000 and narrow polydispersity (Mw/Mn = 1.15–1.16) have been obtained. An unusual step-selective mechanism is suggested for the formation of these polymers.

Super acid catalysis offers the syntheses of a rich variety of similar but different polymer structures otherwise not easily attainable. By this synthetic method, a set of 22 polymers was prepared and their gas permeability coefficients for pure gases, with their associated ideal selectivity, were measured. An analysis of their selectivity and permeability combination protocol revealed that their membranes have combinations, specifically for the O 2 /N 2 , CO 2 /CH 4 and CO 2 /N 2 separations, that are in the same order of magnitude as those reported for the polysulfone and some polyimide families. For CO 2 /N 2 separations, polymers CF 3 PhSO 3 H-T and CF 3 Ph-T offer membranes with CO 2 permeability coefficients of 83 and 220 Barrer, with corresponding selectivity of 31 and 24 . In addition, by the systematic incorporation of Me, Ph, flouro atoms or CF 3 groups into their chemical structure it is possible to understand the structure/properties relationship of gas transport for this series of polymers.

A novel series of linear, high-molecular-weight polymers was synthesized by one-pot, metal-free superacid-catalyzed reaction of isatins (1a−d) with linear, nonactivated, multiring aromatic hydrocarbons: biphenyl (A), p-terphenyl (B), p-quaterphenyl (C), 2-(4-biphenylyl)-6-phenylbenzoxazole (D), 9H-fluorene (E), 9,9-dimethyl-9H-fluorene (F), 2,2′-[2,5-bis(trifluoromethyl)-1,4-phenylene]bis(9,9-dimethyl-9H-fluorene) (G), oligo-9,9-bis(2,6-ethylhexyl)-9H-fluorene (H), biphenol (I), and bi-2-napththol (J). The reactions were performed at room temperature in the Bronsted superacid trifluoromethanesulfonic acid (CF3SO3H, TFSA) and in a mixture of TFSA with methylene chloride or TFA tolerant of hydroxyl, carboxy, and cyano groups. The polymers obtained were soluble in most common organic solvents, and flexible transparent films could be cast from the solutions. 1H and 13C NMR analyses of the polymers synthesized revealed their linear structure with para-substitution in the phenylene fragments of the main chain. ...

We designed and synthesized two novel fluorene monomers of D – A – D (donor–acceptor–donor) type ( M1 and M2 ), and their two corresponding polymers ( PM1 and PM2 ) and a copolymer ( CPM ). These high molecular weight, film-forming polymers were obtained from metal-free, superacid-catalyzed reactions of the monomers with N -phenylisatin. The cubic NLO response ( χ (3) ) for these new compounds, in solid thin films, was measured through the use of third-harmonic generation (THG) Maker-Fringes technique at IR wavelengths given values of the order of 10 −12 esu from which, the corresponding second hyperpolarizabilities ( γ ) were estimated to be of the order of 10 −33 esu for monomers and 10 −31 esu for polymers. Second hyperpolarizabilities have also been estimated theoretically at B3LYP/6-31G(d) level of theory in gas phase and related with the electronic structure of the synthesized molecules.

New polysulfone (PSF) copolymers from bis(4-fluorophenyl)sulfone and based on equimolar mixtures of the rigid/compact naphthalene moiety with bulky connectors from bisphenols: tetramethyl, hexafluoro, and tetramethyl hexafluoro, respectively, were synthesized to measure significant physical properties related to the gas separation field. The flexible and transparent polymer dense films TM-NPSF, HF-NPSF and TMHF-NPSF show high glass transition temperatures Tg congruent to 230 degrees C and high decomposition temperatures To congruent to 400 degrees C (10wt.% loss, in air). Free volume cavity sizes, as determined by PALS, are in the range of 94-139 angstrom(3). Their gas permeability and selectivity combinations of properties, measured at 35 degrees C and 2 atm, are very attractive since their selectivity for the pair of gases H-2/CH4,O-2/N-2, and CO2/CH4 are higher than those for commercial PSF membranes, having similar or superior permeability coefficients for the most permeable gases H-2, O-2, and CO2. Especially important is the tetramethyl naphthalene polysulfone TM-NPSF membrane which reports selectivities for H-2/CH4, O-2/N-2 and CO2/CH4 of 122, 7.6 and 38 with corresponding permeability coefficients (in Barters) of 17 for H-2, 1.2 for O-2, and 5.2 for CO2. These results are interpreted in terms of free volume size and glass transition temperature together with the respective contribution of gas solubility and diffusivity to the overall selectivity coefficients. (C) 2009 Elsevier B.V. All rights reserved.

A novel series of linear, high-molecular-weight polymers was synthesized by one-pot, superacid-catalyzed reaction of pentafluorobenzaldehyde (PFBA) (1) with nonactivated aromatic hydrocarbons: biphenyl, diphenyl ether, p-terphenyl, 4,4′-diphenoxybenzophenone, and 1,3-bis- and 1,4-bis(4′-phenoxybenzoyl)benzenes. The reactions were performed at room temperature in the Bronsted superacid trifluoromethanesulfonic acid (CF3SO3H, TFSA) and in a mixture of TFSA with methylene chloride. The polymer-forming reaction was highly dependent upon the acidity of the reaction medium, as judged from the molecular weights of the polymers obtained. A possible reaction mechanism is suggested. The polymers obtained were soluble in the common organic solvents, and flexible transparent films could be cast from the solutions. 1H and 13C NMR analyses of the polymers synthesized revealed their linear structure. The pendent pentafluorophenyl groups react regioselectively with nucleophiles under basic conditions in polar, aprotic so...

New aromatic 3F polymers were obtained from condensations of 2,2,2-trifluoroacetophenone (1) with biphenyl (a), terphenyl (b), a mixture of biphenyl with terphenyl (ab), phenyl ether (c) and diphenoxybenzophenone (d). The reactions were performed at room temperature in the Bronsted superacid trifluoromethanesulfonic acid (TFSA) and in a mixture of TFSA with dichloromethane. The polymers show high glass transition temperatures >170 °C, excellent thermal stability (decomposition temperatures ≥475 °C) and good solubility in chlorinated solvents and strong acids. The 3F polymer structures based on biphenyl and terphenyl show attractive permeability coefficients for CO2 (∼200 Barrers) and H2 (∼120 Barrers), whereas the 3F polymers that contain ether linkages have permeability coefficients in the typical range of regular polysulfone and polycarbonate. However, in sharp contrast to polysulfone and polycarbonate families, new 3F polymers possess high chemical stability and they have advantages since their reactions, based on commercially available monomers, can be carried out in one-pot at room temperature and offer a large variety of structures not possible to prepare by other synthetic methods.

A series of novel, linear, soluble, high-molecular-weight, fluorinated aromatic polymers has been obtained for the first time using a superacid-catalyzed polyhydroxyalkylation reaction of fluorinated carbonyl-containing compounds: 1,1,1,-trifluoroacetone (1), 2,2,2-trifluoroacetophenone (2), 2,3,4,5,6,-pentafluorobenzaldehyde (3), and octafluoroacetophenone (4) with aromatic hydrocarbons such as biphenyl (a), phenyl ether (b), terphenyl (c), and 4,4'-diphenoxybenzophenone (d). These Friedel-Crafts-type aromatic electrophilic substitution reactions are performed at room temperature in trifluoromethane sulfonic acid or in its mixtures with dichloromethane. The polymers obtained are soluble in common organic solvents, and colorless transparent films could be cast from the solutions. 1 H and 13 C NMR analyses of the polymers synthesized reveal their linear, highly regular structure. The polymers also possess high thermostability.

New cardo poly(aryl ether ketone)s containing side phthalide groups and aryl ether ketones in different lengths have been synthesized and characterized in terms of their thermal, volumetric and gas transport properties to H 2 , O 2 , N 2 , CH 4 and CO 2 . The polymers show high glass transition temperature (218–420 °C), good solubility in chlorinated solvents and strong acids as well as excellent thermal stability (decomposition temperatures above 510 °C). The most permeable membrane studied shows permeability coefficients of 11 to O 2 and 72 to CO 2 , with ideal selectivity factors of 4.6 for the pair O 2 /N 2 and 25 for CO 2 /CH 4 . The results, interpreted in terms of chain rigidity and chain packing ability, show that decreasing the length of the connector moieties between the cardo groups increases the fractional free volume, the glass transition temperature and the gas permeability coefficients.

New polymers containing pyrrole units in the main chain were obtained by chemical modification of diacetylene-containing polymers, which were prepared by oxidative coupling of terminal diacetylenes or superelectrophilic polycondensation of diphenoxydiacetylene with isatin. Diacetylenic fragments in the polymers thus obtained reacted with aromatic amines in the presence of copper chloride to yield the corresponding pyrroles. The reaction between diacetylenic compounds and amines was studied to determine the proper reaction conditions for introduction of pyrrole groups into the polymer backbone. The new polymers and their model compounds were fully characterized by NMR, IR and thermal analysis.

A novel series of linear, high molecular weight polymers were synthesized by one-pot, superacid-catalyzed reaction of acenaphthenequinone (1) with aromatic hydrocarbons. The reactions were performed at room temperature in the Bronsted superacid CF3SO3H (trifluoromethanesulfonic acid, TFSA) and in a mixture of TFSA with methanesulfonic acid (MSA) and trifluoroacetic acid (TFA), which was used as both solvent and a medium for generation of electrophilic species from acenaphthenequinone. The polymer-forming reaction was found to be dependent greatly on the acidity of the reaction medium, as judged from the viscosity of the polymers obtained. Polycondensations of acenaphthenequinone with 4,4‘-diphenoxybenzophenone (f), 1,3-bis(4-phenoxybenzoyl)benzene (g), 1,4-bis(4-phenoxybenzoyl)benzene (h), 1,10-bis(4-phenoxyphenyl)decane-1,10-dione (i), 2,6-diphenoxybenzonitrile (j), 2,6-diphenoxybenzoic acid (k), and 2-(4-biphenylyl)-6-phenylbenzoxazole (l) proceeded in a reaction medium of wide range of acidity, includi...

Spontaneous ring-opening polymerization of macrocyclic aromatic thioether ketones [-1,4-SC6H4CO-C6H4-](n) (n = 3 and 4), in which the thioether linkages are para to the ketone, occurs during rapid, transient heating to 480degreesC, to afford a soluble, semi-crystalline poly(thioether ketone) of high molar mass (eta(inh) > 1.0 dL . g(-1)). Corresponding macrocyclic ether ketone, and a macrocyclic thioether ether ketone in which the thioether linkage is para to the ether rather than to the ketone, show no evidence of polymerization under analogous conditions.

Uncatalyzed, ring-opening polymerization of individual macrocyclic poly(arylene thioether ketone)s (1−4) and mixtures (5) under dynamic heating conditions has been demonstrated for the first time. High-molecular-weight, film-forming products were obtained after heating of the macrocycles up to 480 °C, with a heating rate of 10−20 °C /min. Depending on the macrocyclic structure and heat treatment conditions, the polymers obtained were amorphous or semicrystalline, soluble or slightly cross-linked. NMR analyses of the soluble polymers revealed their linear, highly regular structure. According to NMR, DSC, and TGA studies, the polymers obtained do not contain any residual macrocycles. The polymers with thio-p-arylene moieties in the main chain were thermally stabile. The catalyzed ring-opening polymerization of 5 carried out in diphenyl sulfone solution is also reported for comparison. Using quantum mechanical calculations of the ring opening of macrocycles, a reaction mechanism is suggested. Preparation of ...

Elongated crystalline particles formed as by-products during poly(arylene ether ketone) synthesis by electrophilic precipitation–polycondensation of 4,4′-diphenoxybenzophenone with terephthaloyl chloride or isophthaloyl chloride, thought previously to be polymer-whiskers, have now been identified as macrocyclic phases. Single crystal X-ray analysis of the needle-like particles formed in the reaction with terephthaloyl chloride, using the microdiffraction technique with synchrotron radiation, revealed that they consist of a macrocylic compound containing ten phenylene units, i.e. the [2+2] cyclic dimer. An analogous structure has also been demonstrated for the corresponding macrocycle derived from the reaction of 4,4′-diphenoxybenzophenone with isophthaloyl chloride. Chloroform extraction of the products of the two polycondensations dissolved the macrocyclic material (but not the linear polymer), and analysis of the extracts by MALDI-TOF mass spectrometry demonstrated the presence in both cases of homologous families of macrocyclic products. Higher yields of macrocycles were obtained under pseudo-high dilution conditions, enabling the [2+2] cyclodimers from reactions of 4,4′-diphenoxybenzophenone with both terephthaloyl and isophthaloyl chloride to be isolated as pure compounds and fully characterised.

Aromatic poly(ether−ketone)s having pendant carboxyl groups have been obtained by direct, one-pot, Friedel−Crafts copolycondensation of 4,4‘-diphenoxybenzophenone with a mixture of terephthaloyl chloride (TC) and trimellitic anhydride acid chloride (TAAC), over a wide range of TAAC/TC molar ratios, in the presence of anhydrous aluminum chloride. The syntheses were performed as precipitation−polycondensations, and the polymers were obtained in particulate form. Besides globular particles of polymer, small quantities of elongated, needlelike particles were observed when the mole ratio TAAC/TC was less than 1. Use of X-ray microdiffraction with synchrotron radiation has revealed that the needlelike material consists of a cyclic compound containing 10 phenylene units, i.e., the crystals are of a [2 + 2] macrocyclic dimer. The polymers obtained are soluble in strong acids and in mixtures of methanesulfonic acid or trifluoroacetic acid with chlorinated hydrocarbons. The molecular structures of the polymers were...

A mathematical model for the kinetics and molecular weight development of superacid catalyzed step-growth polymerization of isatin and biphenyl or terphenyl monomers is developed. By considering different reactivities among the several types of polymer molecules present in an otherwise conventional A2 + B2 step-growth polymerization system, ultrahigh molecular weights are predicted by the model for superacid catalyzed polyhydroxyalkylation reactions, a result that remains unclear in the literature since it seems to be in disagreement with the classical A2 + B2 theory. Three polymerization systems are addressed in this study: (a) polymerization of isatin and biphenyl, (b) modified isatin and biphenyl, and (c) modified isatin and terphenyl. Overall good agreement between calculated and experimental results of polymerization rate, and evolution of number- and weight-average molecular weights (Mn and Mw, respectively) is observed. However, some discrepancies for molar mass dispersity (Ð) are observed.

A detailed computational study of possible reaction paths for methanesulfonic and triflic acid mediated polyhydroxyalkylation reaction between resorcinol and trifluoracetone accompanied by cyclodehydration to give 9H-xanthene containing polymers has been carried out at M06-2X/6-311+G** level of theory. A cluster solvation model was used for the calculations. The calculations revealed that the most kinetically favorable reaction path involves the cyclodehydration occurring during the polymer forming step. In this case 9H-xanthene formation is promoted by the activated phenyl ring in Wheland intermediate assisting the aromatic nucleophilic substitution of OH group which leads to the cyclization. It has been demonstrated that the inability of methanesulfonic acid to catalyze the formation of 9H-xanthene containing polymers is due to the very high barrier of the rate limiting step of the polymer forming reaction and not the cyclodehydration process.

Aromatic poly(ether ketone ketone)s (PEKKs) of regular structure, containing 1,3- and 1,4-substituted phthalic acid units in a 1-to-1 ratio, were prepared by two methods: electrophilic and nucleophilic aromatic substitutions. Electrophilic preparations were performed as low-temperature precipitation polycondensations, and resulting polymers were obtained in the form of particles. Nucleophilic syntheses were carried out in N-cyclohexyl-pyrrolidone and diphenyl sulfone at 260°C and 290°C, respectively, in the presence of sodium and potassium carbonates. Differential scanning calorimetry (DSC) curves of the polyketones “as obtained” and “reprecipitated” revealed differences in their thermal behavior depending on the polymerization method, the synthetic route, and the reaction conditions used. The ability of samples to undergo molecular reorganization during heating, affected by polymerization conditions, is responsible for the diversity of DSC curves observed. A parallel X-ray study of the samples revealed s...

Full Paper: The thermal properties and crystal chain packing found for two series (m and p) of oligomeric compounds, with n = 5, 7, 9, and 11 phenylene units, as model compounds for aromatic polyketones are reported. While oligomers of series p contain 1-4 substituted phenylene units those of series m contain an isophthalic group (1-3 substituted phenylene) as the central aryl unit. The keto/ether mole ratio ranges from 0.5 to 0.75. It is confirmed that melting temperatures are clearly dependent on the keto/ether mole ratio as well as on the presence of the isomer defect (isophthalic ring). The keto/ether mole ratio also influences the molecular cross-section and the fusion enthalpy of crystals. Analysis of X-ray diffractograms of the powder samples reveals the presence of lamellar crystals with a thickness corresponding to the length of the linear extended molecular conformation (c axis). Molecular compounds of series p crystallize in the more stable crystal polymorph (form I), observed for aromatic polyketones, while oligomers of series m show polymorphism depending on their chain length. A partial polymeric character of the longest compounds (n = 11) of the two m and p series was found. Nevertheless, their inclusion in this structural study seems to be pertinent.

Linear polyaryl(ether ketones) containing tert-butyl pendent groups were prepared from aromatic hydrocarbons and aromatic diacid chlorides, both classes of monomers containing tert-butyl pendent groups. The polymers were prepared in high yield and high molecular weight by low-temperature precipitation polycondensation in 1,2-dichloroethane. The presence of meta-oriented moieties and bulky pendent groups played a beneficial role with regard to solubility, while the thermal transitions and thermal resistance were not greatly impaired relative to conventional all para-oriented polyaryl(ether-ketones). The current polyaryl(ether-ketones) showed glass transition temperatures in the range 170-240°C and decomposition temperatures, as measured by TGA, of about 500°C.

1,3-Bis(4-phenoxybenzoyl)benzene (1) was crystallized from the glassy state at different temperatures, T c , above the glass transition temperature (Tg = 24°C). Analysis of X-ray diffractograms and DSC thermograms revealed a new polymorphism: a one-dimensional order phase (G1) and a new crystal phase (G2). In both cases the molecules adopt a linear extended conformation. G1 appears for 30°C < T c < 35°C and its structure is like that of a smectic phase A with the molecular axis normal to the layer planes. Upon thermal treatment above 35°C G1 converts into the crystal phase G2 which shows an inproving lateral packing of the molecules upon heating. Gl and G2 show melting temperatures around 88 and 98°C, respectively. Provided that the thermal treatment of the cold crystallizing sample is done under ambient conditions, G2 converts into the most stable crystal phase 2 (T m = 130°C). Similar thermal treatments carried out inside a DSC calorimeter under dry N 2 -flow are not capable of provoking the change in the molecular conformation (from a linear extended to a V-conformation) involved in the crystal phase transition of G2 to phase 2.

SUMMARY: A high molecular weight, linear aromatic poly(ether ketone ether ketone ketone) (PEKEKK) has been synthesized by electrophilic Friedel-Crafts acylation condensation of 1,4-diphenoxybenzophenone with terephthaloyl chloride. The syntheses were performed as precipitation polycondensations, and the polyketones were obtained in particle form. The viscosity (molecular weight), shape and size of these particles were found to be strongly dependent on the reaction conditions. For low monomer concentration, highly ordered needle-like particles were also obtained. The chemical structure of the polymers obtained was confirmed by 'H and 13C NMR spectroscopy, and para-substitution in aryl fragments of the main chain was identified. Analysis of the expanded 'H NMR spectra for the ring proton resonances reveals defect mefa- and ortho-structures. The amount and isomer ratio of these defect structures depend on the monomer concentration used.

High molecular weight, linear aromatic poly(ether ketone ketone)s with different iso-/tere-isomer repeating unit ratio ( 100 0 , 50 50 , 0 100 ) have been studied by 1 H and 13 C n.m.r. spectroscopy. The polymers were obtained in particle form by precipitation electrophilic Friedel-Crafts acylation condensation of iso- and terephthaloyl chlorides with diphenyl ether, 1,4- and 1,3-bis(4-phenoxybenzoyl)benzenes. Conventional 1 H and 13 C n.m.r. spectroscopy shows para -substitution in the diphenyl ether fragments of the main chain. Analysis of the expanded 1 H n.m.r. spectra for the ring proton resonances reveals defect meta - and ortho -structures. The amount and isomer ratio of these defect structures depend on the polymer structure and preparation path. The low field of 1 H n.m.r. spectra of polyketones based on ‘small monomers’ (diphenyl ether and iso- and terephthaloyl chlorides) were found to show additional minor signals corresponding to a different type of defect structure. A possible mechanism of formation of these defect structures is discussed. © 1997 Elsevier Science Ltd.

6 pags., 8 figs., 5 tabs., In the second part of this series the influence of monomer concentration on the chemical structure and the shape and size of poly(aryl ether ketone ether ketone ketone) (PEKEKK) particles was reported. The present study of the thermal behavior and microstructure of aromatic polyketone samples in the form of particles has been carried out by means of differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD). Samples before and after reprecipitation and annealing were investigated. Similar to other polyketones, PEKEKK shows two polymorphic forms: form II, less stable, is currently observed in the samples, while the reprecipitated polymer preferentially shows form I. Form II is partially converted into form I upon short annealing treatment of the material. The semicrystalline materials show melting points and glass transition temperatures which are higher for the samples with higher molecular weight and more regular chain structure. A comparison of thermal properties of “as obtained” and “reprecipitated” samples reveals the influence of the particle architecture on the chain mobility. The latter determines the ability of polyketone chains to crystallize. Infrared dichroism was also used to characterize the arrangement of polymer chains inside the polyketone particles showing crystal habits., Grateful acknowledgment is due to DGICYT, Spain, for the support of this investigation (grant PB94-0049). M.G.Z. also thanks DGICYT for the tenure of a sabbatical grant during his research work in Madrid

Melt-phase nucleophilic ring-opening polymerisation of macrocyclic aromatic ethers and thioethers at high temperatures within the cylindrical pores of an anodic-alumina membrane, followed by dissolution of the template, enables replication of the membrane's internal pore structure and so affords high-performance aromatic polymers with well-defined fibrillar or tubular morphologies.

This report presents a general overview of non-stoichiometric step-growth polymerizations (polycondensations). Three kinds of non-stoichiometric polycondensations are defined and discussed for a(2) + b(2) monomer combinations. Depending on the kinetic scenario and on the experimental conditions, the excess of one monomer either strongly reduces or strongly enhances the average degree of polymerization (DP) relative to a stoichiometric polycondensation under identical conditions. As a result, telechelic oligomers or extremely high molar mass polymers (DPs > 1000) may be formed. Stoichiometric imbalance has in all cases the consequence that cyclization is largely suppressed in early stages of a polycondensation. Finally, non- stoichiometric "a(2) + b(n) " polycondensations are discussed.

Poly(3,3-phthalidylidene-4,4'biphenylylene) (PPB) was considered to be a polymer containing pressure-sensitive moieties as repeating units in the main chain. The effect of pressure on the properties on the properties of PPB was studied. Thin films of the undoped polymer were found to become conductive under slight pressure. The conductivity increases from 10 14 up to 10 -3 Ω -1 .cm -1 under a pressure of about 3.10 5 Pa(0,3 kg/cm 2 ). an effective method is used to visualize the pattern of conducting sites. These may be represented by channels (or domains) in the polymer film

Electroluminescence of thin films of poly(3,3-phthalidylidene-4,4′-biphenylylene) (PPB) and poly(3,3-phthalidylidene-2,7-fluorenylylene) (PPF) was studied. In both cases, electroluminescene was found to be of a threshold origin. Emission maxima and quantum efficiencies for PPB and PPF are 490 and 525 nm, 0.01 and 0.1%, respectively. The electroluminescent characteristics were found to be strongly dependent on the polymer used. Die Elektrochemilumineszenz von dunnen Poly(3,3-phthalidyliden-4,4′-biphenylylen) (PPB) und Poly(3,3-phthalidyliden-2,7-fluorenylylen)-Filmen (PPF) wurde untersucht. Es wird gezeigt, das in beiden Fallen die Elektrochemilumineszenz bei bestimmten Spannungswerten beginnt, die hoher sind als die Schwellenspannungswerte. Die Maximalemissionen sowie die Quanteneffektivitaten der Elektrochemilumineszenz fur PPB und PPF betragen 490 und 525 nm bzw. 0,01 und 0,1%. Die Chemilumineszenzparameter hangen stark vom Polymertyp ab.

The synthesis of poly(3,3-phthalidylidene-4,4′ -biphenylylene) (PPB) by precipitative Friedel-Crafts homopolycondensation of 3-(4-biphenylyl)-3-chlorophthalide was studied. The polymer-catalyst complex precipitated from the initially homogeneous reaction mixture was shown to be active and providing the growth of macromolecular chains. The polymer obtained in the form of smooth, transparent glass-like particles, depending on the reaction parameters, may have either uni- or bimodal molecular weight distribution. Molecular characteristics were not found to depend on the size of the polymer particles. “Precipitative” PPB shows improved properties and higher crystallinity in comparison with “solution” PPB. Die Synthese von Poly(3,3-phthalidyliden-4,4′-biphenylylen) (PPB) durch eine Friedel-Crafts-Fallungspolykondensation von 3-(Biphenyl-4-yl)-3-chlorphthalid wurde untersucht. Der aus der ursprunglich homogenen Reaktionsmischung ausgefallte Polymer-Katalysator-Komplex erwies sich als aktiv und forderte das Wachstum der Polymerketten. Die in Form von glatten, tranparenten, glasartigen Partikeln erhaltenen Polymeren zeigen, abhangig von den Reaktionsparametern, entweder uni- oder bimodale Molekulargewichtsverteilung. Die Polymereigenschaften sind unabhangig von der Partikelgrose. Verglichen mit aus der Losungspolymerisation erhaltenem PPB zeigt das mittels Fallungspolykondensation hergestellte PPB verbesserte Eigenschaften und hohere Kristallinitat.

Interactions of iodine with films prepared from poly(3,3′-phthalidylidene-4,4′-biphenylylene) (PPB) were studied by IR, far-IR and UV spectroscopy. The carbonyl group of the lactone cycle was found to play a main role in the complexation of iodine with PPB. Iodine incorporated into the polymer transforms into polyiodide ions ( I, n = 1 − 3). Various polyiodides, along with complexed iodine (I2comp), may exist in the polymer at a time, and can be transformed into each other, depending on ambient conditions. The process of doping is almost completely reversible. After removal of iodine from the polymer by heating, the latter restores its starting properties.

The behaviour of poly(3,3-phthalidylidene-4,4′-biphenylylene) (PPB) in acidic media was studied. In solvents with high acidity e.g. concentrated sulfuric acid, chlorosulfonic acid or PCl5, the phthalide groups of PPB were transformed into anthracen-9-one groups. Exposure time, solvent and temperature were found to affect the rearrangement of 3,3-diphenylphthalide and PPB in the presence of PCl5. The resulted polymers are soluble in common organic solvents and contain either 10-chloro-10-aryl-anthracen-9-one, or after hydrolysis, 10-hydroxy-10-arylanthracen-9-one units. Flexible and transparent polymer films were prepared by casting from the solution.

The Friedel-Crafts homopolycondensations of 3-(4-biphenyly)-3-chlorophthalide (1 a), 3-(2-fluorenyl)-3-chlorophthalide (1 b), 3-(4-phenoxyphenyl)-3-chlorophthalide (1 c), 3-(4-phenylthiophenyl)-3-chlorophthalide (1 d) were studied. The homopolycondensation of 1 a was found to give linear, fully soluble polymers. A gelation, depending on reaction parameters, can occur in the reactions of 1 b–1 d. The methylene group of 1 b was shown to be reactive in the course of synthesis, giving cross-links. Using the NMR pulsed gradient spin echo method, it was found, that degradation of macromolecular chains in the homopolycondensation of 1 c is followed by gelation. A proposed mechanism of gelation is based on the transformation of intermediate acyloxonium complexes. Similar transformations of acyl-sulfonium complexes are suggested to occur in the course of the homopolycondensation of 1 d.

4-Piperidone and 4-alkyl piperidones react selectively with aromatic hydrocarbons in a mixture of trifluoromethanesulfonic acid (TFSA) and CH(2)Cl(2) to give linear polymers, while N-(2-phenethyl)piperidone undergoes self-polymerization to yield virtually 100%-hyperbranched polymer.

Studies were made on the synthesis of halide-substituted poly(phthalidylidenearylene)s by Friedel-Crafts polycondensations of 3-aryl-3-chlorophthalides containing substituents in 4-position of the phthalide cycle. As follows from the C13 NMR spectra, those monomers can afford polymers containing two types of isomeric units substituted in 4- or 7-position. The possible routes of formation of the isomeric units are analyzed and a scheme is suggested for the monomer rearrangement in the synthetic course. The polymers containing those two types of units were shown to be highly thermostable and to contain about 30% of a crystalline phase.

Poly(oxy-1,4-phenylene carbonyl-1,4-phenylene oxy-1,4-phenylene carbonyl-2,6-naphthalene carbonyl-1,4-phenylene) or 2,6-PEKEKNK is a polymer of the poly(aryl ether ketone) family differing from PEKEKK by the presence of a naphthyl group linked at positions 2 and 6 to the two ketone groups. It is synthesized by electrophilic precipitation polycondensation of 2,6- naphthalenedicarboxylic acid chloride with 4,4’-bis-(4-phenoxy) benzophenone in the presence of aluminium chloride. The dimensions of the orthorhombic unit cell determined from an initially amorphous, stretched film are: a = 0.778 nm, b = 0.613 nm, c = 5.52 nm. In contrast with PEKEKK no signs of polymorphism were found for 2,6 PEKEKNK. Its glass transition and melting temperatures are 20 °C and 2 °C above those of PEKEKK, respectively.

The structure and thermal properties of polymers containing dibenzo-18-crown-6 ether units in the main chain linked to an aliphatic spacer of different lengths (C10-C14) is reported. X-ray diffraction patterns of all the studied samples exhibit a peak in the medium angle region, revealing the existence of a lamellar structure. Simultaneous calorimetry and small, medium (SAXS-MAXS) and wide (WAXS) X-ray measurements during cooling and subsequent heating of the samples reveal that a layer phase is formed upon cooling. In the case of the homopolymers, this phase is almost simultaneously accompanied by the appearance of some reflections in the wide angle region as an indication of lateral crystallization. However, by copolymerization, the formation of the layer phase is decoupled from lateral crystallization, being stable in a wide temperature region. © 2007 American Chemical Society., Spanish Ministry of Science and Education for the financial support of this project (Grant MAT2005-01768). DGAPA, Mexico (Project PAPIIT IN101405-3). Ramón y Cajal program of the Spanish Ministry of Science and Education

Novel, linear, soluble, high-molecular-weight, film-forming polymers and copolymers in which main-chain crown ether units alternate with aliphatic (C10-C16) units have been obtained for the first time from aromatic electrophilic substitution reactions of crown ethers by aliphatic dicarboxylic acids followed by reduction of the carbonyl groups. The crown ether unit is dibenzo-18-crown-6, dibenzo-21-crown-7, dibenzo-24-crown-8, or dibenzo-30-crown-10; the aliphatic spacer is derived from a dicarboxylic acid (sebacic, 1,12-dodecane-dicarboxylic, hexadecanedioic or 1,4-phenylenediacetic acids). The reactions were performed at 35°C in a mixture of methanesulfonic acid (MSA) with phosphorus pentoxide, 12:1 (w/w), (Eaton's reagent). The carbonyl groups in the polyketones obtained were completely reduced to methylene linkages by treatment at room temperature with triethylsilane in a mixture of trifluoroacetic acid and dichloromethane. Polymers containing in the main chain crown ethers alternating with oxyindole fragments were prepared by one-pot condensation of crown ethers with isatin in a medium of Eaton's reagent. A possible reaction mechanism is suggested. According to IR and NMR analyses, the polyacylation reactions lead to the formation of isomeric (syn/anti-substituted) crown ether units in the main chain. The polymers obtained were soluble in the common organic solvents, and flexible transparent films could be cast from the solutions. DSC and X-ray studies of the polymers with >symmetrical> crown ethers reveal the presence of the endotherms corresponding to the supramolecular assemblies. © 2006 American Chemical Society., DGAPA (project PAPIIT IN101405-3)