Soluble polystyrenes with pyrrole pendant groups and their electroactive properties

Summary Four soluble styrenic polymers containing 3-substituted pendant pyrrole rings with ester or amide arm spacer were synthesized. Their electroactive characteristics were investigated by cyclic voltammetry. The chemical oxidation was accomplished by adding FeCl₃ into a solution of styrenic polymers dissolved in 1:1 mixture of dimethylformamide (DMF) and acetonitrile (ACN). The electrical conductivities of the chemically oxidized black powder of the styrenic polymers were in the range of 10^-1010^-9 S/cm.     

Polyphenylquinoxalines containing pendant phenylethynyl groups: Preliminary mechanical properties

Polyphenylquinoxalines (PPQ's) containing various amounts of crosslinkable pendant phenylethynyl groups were prepared from the reaction of 3,3′,4,4′-tetraaminodiphenyl ether, 4,4′-oxydibenzil, and 4,4′-oxybis(4″-phenylethynylbenzil). The distribution of the pendant phenylethynyl groups along the polymer chain was varied in an attempt to alter the properties of the polymers. Preliminary film, adhesive, and laminate properties of PPQ void of pendant crosslinkable groups and containing pendant phenylethynyl groups were determined. The thermally induced reaction of the phenylethynyl group crosslinked the polymer which resulted in better dimensional stability at elevated temperatures.     

Plasticizer properties of some acrylonitrile-eleostearate adducts and their hydrogenated derivatives

Summary The addition products obtained by the Diels-Alder reaction of acrylonitrile with the methyl, ethyl, and butyl eleostearates have been prepared in good yields and purified by means of high-vacuum distillation. It has been possible to saturate preferentially by hydrogenation both the cyclic and exocyclic double bonds of the acrylonitrile adducts without material reduction of the nitrile group. Also the acrylonitrile adduct of tung oil has been prepared. All these adducts have been intercompared with DOP and evaluated as primary plasticizers for vinyl chloride-vinyl acetate copolymer. These products, with the exception of the nonhydrogenated ethyl and butyl derivatives, were found to be satisfactory as primary plasticizers. The results obtained indicate that hydrogenation greatly improves the compatibility of the adducts without changing their other plasticizing characteristics appreciably. The outstanding characteristic of all the adducts is their high plasticizing efficiency, as reflected by their low modulus at 100% elongation. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Preparation and thermal properties of acrylic polymers with pendant spirobislactone groups

A series of acrylic terpolymers containing varying concentrations of crosslinkable glycidyl, spirobislactone, and hydroxyl pendant groups was prepared by radical chain polymerization. The glass-transition temperatures and weight average molecular weights of the terpolymers span broad ranges and can be independently selected by control of monomer composition. Cross-linking at 210°C was monitored by infrared spectroscopy. The rate and extent of reaction of spirobislactone groups were found to be greater than those for glycidyl groups. The activation energies of the spirobislactone and glycidyl reactions in the range between 160 and 210°C were calculated by Arrhenius treatment of the curing kinetics and found to be 31.0 ± 1.1 kJ mol^?1 and 59.1 ± 1.2 kJ mol^?1, respectively. The double ring opening reaction of the spirobislactone groups has no effect on the volume of the cross-linked polymers. © 1994 John Wiley & Sons, Inc.     

Dynamic mechanical properties of some nylons and their blends

The dynamic mechanical properties of nylons 6, 11, 12, 66, 610, 612, and 666 are compared. The spectra are very similar with peaks in the loss curves at about ?120, ?40, and 85°C. The similarity suggests that attempts to determine whether the nylons could in fact be incompatible when blended might not be successful. Calculations based in turn on calculated cohesive energy densities and interaction parameters also suggest that only nylon, 6 and 66 would be compatible. By using the nature of the major loss peak at the glassy transition which is high and narrow for nylons 11 and 12 and broader and shorter for nylons 6, 66, and 666, it is possible to deduce that nylons 6 and 12 are somewhat incompatible but that the other combinations are most likely dynamically compatible.     

Preparation and properties of ester or cyano group substituted ring-opening polymers and their hydrogenated derivatives

Ester or cyano substituted tetracyclo [4.4.0.1^2,5.1^7,10]dodec-3-enes (1) were synthesized and their metathesis ring-opening polymerization was examined. The tungsten-based ternary catalyst system polymerized them very well. The polymers showed high glass transition temperatures (T_g) and no evidence of crystallization (e.g., the T_g of the polymer derived from 8-methyl-8-methoxycarbonyl substituted monomer (1a) was 207°C, and colorless transparent films could be casted from the solution of the polymer). The stability of these high T_g polymers were too unstable, so practical thermal molding methods could not be applied to them. The hydrogenation of these polymers with a palladium catalyst decreased T_g and greatly increased thermal stability. The physical and thermal properties of the hydrogenated polymers were thoroughly investigated. Monomer 1 was successfully copolymerized with other cyclic olefins. The resultant copolymers were hydrogenated, giving thermally stable polymers. In all cases examined in this study, a decrease of T_g by hydrogenation was about 35°C, regardless of the monomer structure. These results indicate that the main-chain mobility is the major contribution to the decrease of T_g. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 367–375, 1997     

Preparation of polymers with pendant quinonoid groups and their photocrosslinking with visible light irradiation

Photosensitive polymers with pendant quinonoid groups were prepared by the reaction of p-(benzoquinon-2-ylthio) acetic acid (QTAA) or p-(p-benzoquinon-2-ylthio)benzoic acid (QTBA) with hydroxyethyl methacrylate-methyl methacrylate copolymer. The polymers showed a strong π-π^* absorption band at around 410 nm and were efficiently crosslinked by visible light irradiation. Somewhat higher photosensitivity of QTAA-bound polymer compared with that of QTBA-bound polymer suggested some contribution of intramolecular hydrogen abstraction of QTAA to the photocrosslinking.     

Synthesis and properties of polynorbornenes bearing oligomeric siloxane pendant groups

The ring-opening metathesis polymerization (ROMP) of norbornene derivatives 1-5 bearing oligomeric siloxane pendant groups was carried out with Grubbs 1st and 2nd generation, and Grubbs-Hoveyda ruthenium (Ru) catalysts. Monomer 1 gave high-molecular-weight polymers (M_n ca. 27?000-180?000) in high yields (80-100%). Monomers 2-5 also polymerized with Ru carbene catalysts to give high-molecular-weight polymers (M_n ca. 34?000-240?000) in high yields (66-100%). The onset temperatures of weight loss (T₀) of the polymers were 180-250 °C. The glass transition temperatures (T_gs) of poly(1) and poly(2) bearing branched siloxane linkages were near or higher than room temperature (27 and 101 °C). Meanwhile, the T_gs of poly(3)-poly(5) bearing linear siloxane linkages were much lower (−115 to −23 °C), and decreased with increasing length of the siloxane linkages. Poly(1) and poly(2) were hydrogenated completely, which was confirmed by ¹H NMR spectroscopy. The free-standing membranes of poly(1) and poly(2) showed high gas permeability; especially poly(2) is the most permeable to various gases among ROMP-polynorbornene derivatives reported so far.     

Synthesis and properties of a modified unsaturated polyester resin with phosphorus-containing pendant groups

A novel modified-unsaturated polyester resin (M-UPR) with phosphorus-containing pendant groups was successfully prepared by employing a bifunctional acid, 2-[10-(9,10-dihydro-9-oxa-10-phosphaphenantrene-10-oxide-10-yl)]-maleic acid (DOPO-MA) as monomer. Characterization of DOPO-MA and M-UPR was performed using element analysis, ¹H-NMR, or FT-IR. The curing of M-UPR was measured by differential scanning calorimetry, and the optimal cure temperature was calculated with DSC curves at different heating rates. The thermal stability was investigated with thermogravimetric analysis and comparative FT-IR analysis for char residue before and after heating. The flame-retardant property was determined by limiting oxygen index measurements and UL94 flammability meter. The viscoelastic property was measured with dynamic mechanical analysis. Owing to the incorporation of the rigid structure of pendant phosphorus groups, both thermal stability and flame retardancy of the resultant M-UPR have been improved.     

Synthesis and properties of poly(phenylacetylene)s with pendant imino groups

Summary Polymerization of phenylacetylenes containing imino groups with a variety of transition metal catalysts was investigated. The monomers employed were N-(4-ethynylbenzylidene)aniline (1), N-(3-ethynylbenzylidene)aniline (2), N-(4-ethynylbenzylidene)-2,6-diisopropylaniline (3), N-(4-ethynylbenzylidene)-4-hexylaniline (4), N-(4-ethynylbenzylidene)butylamine (5), and N-(4-ethynylbenzylidene)octylamine (6). All of the monomers smoothly polymerized with [(nbd)RhCl]₂-Et₃N to give polymers in excellent yields, whereas no polymerization took place with W, Mo, and Fe catalysts. The produced polymers were orange to red solids and soluble in common organic solvents except for poly(1). UV-vis spectra of the polymers indicated that the main chains possess a similar degree of conjugation to that of poly(phenylacetylene). However, the stability of polymer backbone toward oxidative cleavage in solution remarkably improved, which is contributed by the electron-withdrawing character of imino groups. Received: 24 August 1999/Accepted: 29 September 1999     

Synthesis and properties of poly ether nitrile sulfone copolymers with pendant methyl groups

Poly ether nitrile and poly ether nitrile sulfone copolymers with pendant methyl groups were prepared by the nucleophilic substitution reaction of 2,6′‐dichlorobenzonitrile with methyl hydroquinone and with varying mole proportions of methyl hydroquinone and 4,4′dihydroxydiphenylsulfone using N‐methyl pyrrolidone as solvent in the presence of anhydrous K₂CO₃. The polymers were characterized by different physicochemical techniques. Copolymer composition was determined using FTIR technique. Thermogravimetric data reveals that all the polymers were stable up to 420°C with a char yield above 40% at 900°C in N₂ atmosphere. The glass transition temperature was found to increase and the activation energy and inherent viscosities were found to decrease with increase in concentration of the 4,4′‐dihydroxydiphenylsulfone units in the polymer. Trimerization reactions are found to be favorable with increase in concentration of methyl hydroquinone units in the polymer. Crystallinity of the polymer was also studied using wide angle X‐ray diffraction. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1303–1309, 2006     

Sulfonated polynaphthalimides with benzimidazole pendant groups

A series of new polyimides bearing simultaneously sulfonic acid groups and benzimidazole rings in different proportions have been synthesised by one pot high temperature polycondensation. The composition of the copolymers, as well as the distribution of the ionic sites along the polymer chain, has been changed systematically in order to study their relation with polymer properties. The incorporation of sulfonic side groups in the structure improves the solubility in polar organic solvents. In turn, the presence of sulfonic acid moieties impairs thermal resistance. Membranes based on the synthesised polyimides were prepared by solution casting and their water uptake as well as proton conductivity were determined.     

Novel ionenes with allyl pendant groups

Summary Novel ionenes with allyl pendant groups have been synthesized by condensation of N,N'- bisallylpiperazine with organic dihalides such as 1,4-dichlorobutane, 1,6-dibromohexane and 1,4-dichloromethylbenzene. The polymers are readily soluble in water and have low molecular weights. The structure of the ionenes has been identified by spectroscopic techniques. The concentrated aqueous solutions of the resulting ionenes can be crosslinked by t-butylhydroperoxide as a radical initiator to give transparent hydrogels. The ionenes also act as an crosslinking agent in copolymerization with high concentrations of acrylic acid in the presence of K₂S₂O₈ as a radical initiator in water at 65°C. Received: 29 July 1999/Revised version: 28 October 1999/Accepted: 28 October 1999     

Surface-modified kevlar fiber-reinforced ionomer: Dynamic mechanical properties and their interpretation

A quasi-three-dimensional model was applied to the composite of ionomer and isotropically oriented discontinuous poly(p-phenylene terephthalamide) (PPTA) fibers having the surface modified by carboxymethyl groups in order to predict the Young's modulus from the properties of the constituent materials over a wide temperature range. The model in which the modified PPTA fibers are dispersed in ionomer matrix in a three-dimensional network is composed of series and parallel models. A good agreement between calculated and experimental values was eventually obtained. For comparision, the complex modulus of the composite was also evaluated by application of the Halpin-Tsai equation modified by Nielsen. The calculated values agreed with the observed values below 240 K, whereas the calculated values above 260 K were significantly lower than the observed moduli.     

New polyelectrolytes by ring-opening metathesis polymerization of norbornene derivatives with imidazolium functionalized oligo-alkylether pendant groups

Novel monomers are reported that are derived from norbornene functionalized with oligoethyleneoxy groups that carry imidazolium salts. These monomers were polymerized via ruthenium-catalyzed ring-opening metathesis polymerization in a variety of solvents, including ionic liquids, at different temperatures to give novel low T_g polymers. These polymers are expected to act as new polymer electrolytes.     

Fluorene oligomer with tetrathiafulvalenes as pendant groups: synthesis,electrochemical and spectroscopic properties

An oligomeric fluorene with pendant TTF units (OFT) was synthesized by the Yamamoto coupling reaction using Ni(COD)₂ as catalyst. The fluorescence spectra of fluorene-TTF (3a) and OFT displayed weak fluorescence intensity because of the photoinduced electron transfer (PET) interaction and energy transfer between the TTF and fluorene, while the fluorescence intensity would enhance significantly after chemical oxidation. The absorption spectra and cyclic voltammetry (CV) showed that an intramolecular interaction existed between the TTF and fluorene moieties in OFT, while in 3a such interaction could not be observed, due to the chain propagation of the fluorene backbone and an enhanced internal charge transfer interaction between the two electroactive moieties. Moreover, the conductivity showed that the doped OFT possessed a higher conductivity (1.4 × 10⁻³ S cm⁻¹) than the doped 3a (9.8 × 10⁻⁵ S cm⁻¹). These results demonstrated that OFT was a good candidate of fluorescence switches and conducting materials.     

Structural effects of pendant groups on thermal and electrical properties of polyimides

Two series of aromatic polyimides containing various‐sized alkyl side groups were synthesized by thermal imidization of the poly(amic acid)s prepared from the polyaddition of benzophenonetetracarboxylic dianhydride and hexafluoro‐isopropylidene bis(phthalic anhydride) with 4,4′‐methylenedianiline, 4,4′‐methylene‐bis(2,6‐dimethylaniline), 4,4′‐methylene‐bis(2,6‐diethylaniline), and 4,4′‐methylene‐bis(2,6‐diisopropylaniline). The extent to which alkyl substitutes affect the thermal properties of polyimides was examined by differential scanning calorimetry, thermomechanical analyzer, and thermogravimetric analysis techniques. The analytical results demonstrated that the incorporation of alkyl moieties causes a moderate increase in the coefficient of thermal expansion and a slight decrease in thermal stability. Notably, all polymers had a decomposition temperature exceeding 500°C. The glass transition temperature increases markedly when hydrogen atoms at ortho positions on aniline rings are replaced with methyl groups, but decreases with growing alkyl side group size. The dielectric measurements show that the polymer possessing a large alkyl side group would have the lower dielectric value. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4672–4678, 2006     

Synthesis and properties of poly(ether nitrile sulfone) copolymers with pendant methyl groups

Poly(ether nitrile) and poly(ether nitrile sulfone) copolymers with pendant methyl groups were prepared by the nucleophilic substitution reaction of 2,6′‐dichlorobenzonitrile with methyl hydroquinone and with varying mole proportions of methyl hydroquinone and 4,4′‐dihydroxydiphenylsulfone using N‐methyl pyrrolidone as a solvent in the presence of anhydrous K₂CO₃. The polymers were characterized by different physicochemical techniques. Copolymer composition was determined using the FTIR technique. Thermogravimetric data revealed that all polymers were stable up to 420°C with a char yield above 40% at 900°C in a nitrogen atmosphere. The glass‐transition temperature increased and the activation energy and inherent viscosities decreased with an increase in the concentration of the 4,4′‐dihydroxydiphenylsulfone units in the polymer. Trimerization reactions were favorable with an increase in the concentration of methyl hydroquinone units in the polymer. The crystallinity of the polymer was also studied using wide‐angle X‐ray diffraction. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1987–1994, 2005     

Synthesis of new polyesters with methacrylate pendant groups

Summary A catalytic process for synthesis of new polyesters with methacrylate pendant groups is presented. Thus, zinc succinate catalyzed reaction of succinic anhydride with glycidyl methacrylate (GMA) in dimethoxyethane gives linear oligoesters with low molecular weights (1380-2400 Da). The polyester formation takes place via simultaneous ring opening of the cyclic anhydride and oxirane units. GMA component can be partially replaced with cyclohexeneoxide to obtain polyesters with methacrylate pendant groups in various percentages. Nearly colorless waxy polymers are obtained in excellent yields (69–97%) within 48–60 h. at 90 °C. In the study structure of the polymers have been elucidated by conventional spectroscopic techniques and photo-crosslinking of ability of their thin films have been tested by monitoring intensity of methacrylate double bonds, using IR-spectrometry methodology.