Ambient‐temperature copper‐catalyzed atom transfer radical polymerization of methacrylates in ethylene glycol solvents

The use of ethylene glycol solvents in the room‐temperature atom transfer radical polymerization (ATRP) of various hydrophobic and hydrophilic methacrylates is demonstrated. Unlike many of the very polar solvents described in the literature for room‐temperature ATRP, these solvents have good solvency for a wide range of polymers and monomers and are cheap and relatively nontoxic. Ethylene glycols with one hydroxyl and one methoxy group, such as tri(ethylene glycol) monomethyl ether (TEGMME), provide optimal results. The polymerization of methyl methacrylate in TEGMME with CuBr/N,N,N′N′,N″‐pentamethyldiethylenetriamine as the catalyst requires the addition of CuCl₂ at the beginning of the reaction to produce well‐controlled polymerizations. This leads to polymers with predictable molecular weights and relatively narrow polydispersities. Polymerization in solvents that are fully methoxy‐capped terminate prematurely because of catalyst precipitation. The electrochemical behavior of copper complexes in selected solvents is examined to determine why these solvents provide good rates at room temperature. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1588–1598, 2005     

Synthesis and characterization of novel polyaryloxydiphenylsilane derived from 2,2′- dimethyl-biphenyl-4,4′-diol

A novel polyaryloxydiphenylsilane was synthesized successfully by solution polycondensation of 2,2′-dimethyl-biphenyl-4,4′-diol with diphenyldichlorosilane and the catalyst triethylamine in toluene at 80 °C. Polymers with a relatively high inherent viscosity and yield were obtained when the reactions were carried out in aromatic and lipophilic solvents. The novel polyaryloxydiphenylsilane was soluble in chlorinated aliphatic hydrocarbons such as methylene chloride and chloroform as well as in polar solvents such as dimethyl sulfoxide, N,N-dimethylformamide, and N,N-dimethylacetamide and also in some common organic solvents such as benzene and toluene. However, it was insoluble in both aliphatic hydrocarbons as well as in alcoholic solvents. The polyaryloxydiphenylsilane began losing weight around 400 °C under a nitrogen atmosphere, and the 10% weight-loss temperature was 473 °C. The glass-transition temperature of the polyaryloxydiphenylsilane was 102 °C. The glass transition could be lowered by the copolymerization technique with 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane as an aromatic diol comonomer. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4591–4595, 1999     

Synthesis of poly(methyl methacrylate) via ARGET ATRP and study of the effect of solvents and temperatures on its polymerization kinetics

This investigation reports the synthesis of poly(methyl methacrylate) via activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) and studies the effect of solvents and temperature on its polymerization kinetics. ARGET ATRP of methyl methacrylate (MMA) was carried out in different solvents and at different temperatures using CuBr₂ as catalyst in combination with N,N,N′,N″,N″‐pentamethyldiethylenetriamine as a ligand. Methyl 2‐chloro propionate was used as ATRP initiator and ascorbic acid was used as a reducing agent in the ARGET ATRP of MMA. The conversion was measured gravimetrically. The semilogarithmic plot of monomer conversion versus time was found to be linear, indicating that the polymerization follows first‐order kinetics. The linear polymerization kinetic plot also indicates the controlled nature of the polymerization. N,N‐Dimethylformamide (DMF), tetrahydrofuran (THF), toluene, and methyl ethyl ketone were used as solvents to study the effect on the polymerization kinetics. The effect of temperature on the kinetics of the polymerization was also studied at various temperatures. It has been observed that polymerization followed first‐order kinetics in every case. The rate of polymerization was found to be highest (k_app = 6.94 × 10⁻³ min⁻¹) at a fixed temperature when DMF was used as solvent. Activation energies for ARGET ATRP of MMA were also calculated using the Arrhenius equation.     

Synthesis and characterization of N‐benzoylated wholly aromatic polyamides from 4,4′‐oxydianilinobis(benzimidoyl) chloride and aromatic dicarboxylic acids

A novel type of polyamides, N‐benzoylated wholly aromatic polyamides, were synthesized by low‐temperature solution polycondensation of a new aromatic bis(imidoyl) chloride, 4,4′‐oxydianilinobis(benzimidoyl) chloride, with aromatic dicarboxylic acids, 4,4′‐oxydibenzoic acid and isophthalic acid. Compared with the conventional all aromatic polyamides and also N‐phenylated wholly aromatic polyamides, these N‐benzoylated aramides exhibit better solubility in organic solvents, lower glass transition temperatures and thermal stability.     

Synthesis of polyamides from active O,O′-diacyl derivatives of N-hydroxy compounds and diamines under mild conditions

Two new routes to polyamides were established, based on the polycondensation of two new typical active diesters: the active diester of N-hydroxy-5-norbornene-2,3-dicarboximide, such as N,N′-(terephthaloyldioxy)bis(5-norbornene-2,3-dicarboximide), and the active diester of 3-hydroxy-4-oxo-3,4-dihydro-1,2,3-benzotriazine, such as 3,3′-(isophthaloyldioxy)bis(4-oxo-3,4-dihydro-1,2,3-benzotriazine) with diamines. The polycondensation occurred at room temperature in solution without added catalyst. Dipolar aprotic solvents which included dimethyl sulfoxide and N-methyl-2-pyrrolidone were used as solvents for polymerization. Before polymer synthesis the aminolysis of two active monoesters was carried out as a model compound study.     

Synthesis and characterization of N-phenylated aromatic polyureas from dianilino compounds and aromatic diisocyanates

N-phenylated aromatic polyureas were synthesized by the polyaddition of dianilino compounds to aromatic diisocyanates in sym-tetrachloroethane at around 100°C. Factors that influence the reaction, such as monomer concentration, reaction solvent, catalyst, temperature, and time, were studied to optimize the conditions for the preparation of high molecular weight polymers. Compared with the analogous unsubstituted aromatic polyureas, the N-phenylated polyureas were almost amorphous and soluble in a variety of solvents and had low glass transition temperatures. Some of the polymers could be cast into transparent flexible films from chloroform solutions.     

Novel Soluble Polyimide Containing 4-tert-Butyltoluene Moiety: Synthesis and Characterization

Based on the synthesis of a rigid aromatic diamine, α,α‐bis(4‐aminophenyl)‐4‐(t‐butyl)toluene ( 1 ), a novel polyimide (PI) 3 was prepared from this diamine monomer and 4,4′‐oxydiphthalic dianhydride via a one‐step high‐temperature polycondensation. FT‐IR, ¹H NMR and elemental analysis were used to investigate the chemical structures of 1 and 3 . The results confirmed that they agreed with the proposed structures for both 1 and 3 completely. The obtained PI 3 showed excellent solubility in most common solvents such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide, N,N‐dimethylformamide, chloroform, dichloromethane and tetrahydrofuran. The resulting strong and flexible film exhibited high thermal stability with the glass transition temperature at 317°C and the temperature at 10% weight loss beyond 519°C in both air and nitrogen atmospheres. Moreover, the film also showed high optical transparency, low dielectric constant (3.13 at 1 MHz), low water absorption (0.40%) and hydrophobic character.     

Synthesis of polymaleamides by ring-opening polyaddition reaction of N,N′-disubstituted bisisomaleimides with diamines

The ring-opening polyaddition reaction of N,N′-disubstituted bisisomaleimides with various diamines in N-methyl-2-pyrrolidone at room temperature afforded polymaleamides having inherent viscosity up to 0.7 in almost quantitative yield. These polymers are a new class of homopolymaleamides and ordered alternating copolymaleamides. Almost all of the polyamides were soluble in a wide range of solvents such as dimethylsulfoxide, dimethylacetamide, m-cresol, and formic acid. They did not show any melt temperature, and began to decompose at a temperature ranging between 200 and 300°C.     

Polymerizations of some diene monomers. Preparations and polymerizations of vinyl methacrylate,allyl methacrylate,N-allylacrylamide,and N-allylmethacrylamide

Vinyl methacrylate, allyl methacrylate, N-allylacrylamide, and N-allylmethacrylamide were prepared, and these monomers were polymerized in toluene by α,α-azobisisobutyronitrile catalyst. Cyclization content of poly(vinyl methacrylate) was estimated by infrared spectroscopy to be 50–60% at low conversions, but at the high conversions, due to gelation the polymers were insoluble in the usual organic solvents. Allyl methacrylate did not produce any soluble polymer, even at a low conversion, in contrast with poly-(vinyl methacrylate). Poly-N-allylacrylamide and poly-N-allylmethacrylamide were also insoluble in common solvents. It was assumed that the polymers from monomers containing the allyl group might form crosslinks as a result of allyl resonance stabilization.     

Preparation and properties of fluorine-containing aromatic polyamides from tetrafluorophthaloyl chlorides and aromatic diamines

New fluorine-containing aromatic polyamides with inherent viscosities of 0.4–1.8 dL/g were prepared by the low temperature solution polycondensation of tetrafluoroisophthaloyl and tetrafluoroterephthaloyl chlorides with N,N′-bis(trimethylsilyl)-substituted aromatic diamines. The aromatic polyperfluoroisophthalamides were amorphous polymers with glass transition temperatures around 280°C, whereas the polyperfluoroterephthalamides were crystalline. Most of these aromatic polyamides were soluble in organic solvents, and began to decompose around 330°C in air or nitrogen atmosphere.     

Soluble fluorinated polyimides derived from 1,4‐ (4′‐aminophenoxy)‐2‐(3′‐trifluoromethylphenyl)benzene and aromatic dianhydrides

New fluorinated aromatic polyimides were prepared from 1,4‐(4′‐aminophenoxy)‐2‐(3′‐trifluoromethylphenyl)benzene and aromatic dianhydrides via the polycondensation of one‐step high‐temperature and two‐step thermal or chemical imidization methods. Experimental results indicated that some of the polyimides were soluble both in strong dipolar solvents (N‐methyl‐2‐pyrrolidone or N,N‐dimethylacetamide) and in common organic solvents such as tetrahydrofuran, CHCl₃, and acetone. The polyimides showed exceptional thermal and thermooxidative stability and good mechanical properties. No weight loss was detected before a temperature of 520 °C in nitrogen, and the glass‐transition temperatures ranged from 208 to 251 °C. Low dielectric constants (2.55–2.71 at 1 MHz), low refractive indices, and low water absorption were also observed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2404–2413, 2001     

Synthesis of polyhydrazides by ring-opening polyaddition reaction of N,N′-biisomaleimide with dihydrazine and dihydrazides

The ring-opening polyaddition reaction of N,N′-biisomaleimide with a dihydrazine and dihydrazides was carried out in polar aprotic solvents at room temperature to afford a new class of polyhydrazides having inherent viscosities in the range of 0.1–0.5 in nearly quantitative yields. Almost all of the polyhydrazides were soluble in dimethylformamide, dimethyl sulfoxide, and other polar aprotic solvents. They did not show any clear melt temperature and began to decompose at around 200–300°C.     

Oxidative Coupling Reaction of N,N‐Dialkylanilines with Cerium(IV) Ammonium Nitrate in the Solid State

Oxidative coupling reactions of N,N‐dialkylanilines with cerium(IV) ammonium nitrate can be achieved by grinding at room temperature in the absence of solvents.     

Polymerization of N-vinylcarbazole by transition metal salts

The polymerization of N-vinylcarbazole (NVC) in the presence of transition metal salts such as WCI₆, MoCI₅, TaCl₅ and NbCl₅ under different reaction conditions was studied. In general, aromatic solvents were found to be superior to aliphatic solvents in the polymerization of NVC, i. e., both conversion and molecular weight were higher in aromatic solvents. It was observed that the polymerization reaction proceeds rapidly and almost quantitatively, even at low monomer concentration (< 5 × 10^?2M) and at low catalyst to monomer mole ratio (10^?5) in aromatic solvents. The copolymerization of NVC with acenaphthylene (ACN) was also investigated in solution at room temperature. The resulting homo- and copolymer were characterized by IR, NMR, x-ray diffraction, and elemental analysis. Thermal and photophysical properties are also reported. From the spectral data, the polymerization solvent was found to have a strong influence upon the polymer stereoregularity.     

Synthesis and characterization of silicon-containing phenylated soluble aramids

New high molecular weight (inherent viscosities, 1.21–0.50 dL/g) aramids having silicon and pendant phenyl groups were synthesized by low temperature interfacial polycondensation technique involving the reaction of acid chlorides: bis(4-chlorocarbonylphenyl)dimethylsilane and bis(3-chlorocarbonylphenyl)dimethylsilane with diamines: 2,5-bis(4-aminophenyl)-3,4-diphenyl-thiophene and bis(4-aminophenyl)ether. Copolyamides were obtained by using different proportions of these diamines. All the polymers were completely soluble in organic solvents such as N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and N,N-dimethylformamide. Thermal properties were evaluated by thermogravimetry which showed no weight loss below 325°C in both air and nitrogen atmospheres.     

Synthesis and characterization of aromatic polyamides from 1,1-bis(4-aminophenyl)-2,2-diphenylethylene and aromatic diacid chlorides

Novel, soluble aromatic polyamides and copolyamides containing tetraphenylethylene units were prepared by the low temperature solution polycondensation of 1,1-bis(4-aminophenyl)-2,2-diphenylethylene and aromatic diamines with various aromatic diacid chlorides. Highmolecular-weight polyamides having inherent viscosities of 0.6–1.5 dL/g and number-average molecular weight above 21000 were obtained quantitatively. These polymers were readily soluble in various solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide (DMAc), and dimethyl sulfoxide and gave pale yellow, transparent, flexible films by casting from DMAc solution. The polymers had glass transition temperatures between 290 and 340°C, and started to lose weight around 400°C, with 10% weight loss being recorded at about 470°C in air.     

Synthesis of polyacylsulfonamide-amides by ring-opening polyaddition of N,N′-arylenedisulfonylbissuccinimides with diamines

Ring-opening polyaddition of N,N′-arylenedisulfonylbissuccinimides with both aliphatic and aromatic diamines in N-methyl-2-pyrrolidone at room temperature afforded polyacylsulfonamide-amides having inherent viscosities in the range of 0.2–0.4 in excellent yields. The polymers revealed acidic nature and were readily soluble in both polar aprotic solvents and basic media. They melted at a temperature below 200°C and began to decompose at around 250°C in nitrogen.     

Synthesis and characterization of soluble aromatic polyurea-amides from new N,N′--dimethyl-N,N′-bis(aminophenyl)ureas and aromatic dicarboxylic acid chlorides

Aromatic polyurea-amides having inherent viscosities of 0.36–0.67 dL/g were synthesized by the low temperature solution polycondensation of new N,N′-dimethyl-N,N′-bis(aminophenyl)ureas with various aromatic dicarboxylic acid chlorides. All the polymers were amorphous, and most of them were soluble in a variety of organic solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide (DMAc), m-cresol, and pyridine. Some of the polymers could be cast from the DMAc solutions into transparent and flexible films having good tensile properties. The glass transition temperatures of the polyurea-amides obtained from the bis(4-aminophenyl)-substituted ureas were 244–272°C. The temperatures of 10% weight loss under nitrogen of the polymers were in the range of 430 and 480°C. © 1995 John Wiley & Sons, Inc.     

Synthesis and characterization of soluble aromatic polyamides from 2,5-bis(4-aminophenyl)—3,4-diphenylthiophene and aromatic diacid chlorides

New soluble aromatic polyamides with inherent viscosities of 1.0–1.7 dL/g were prepared by the low temperature solution polycondensation of 2,5-bis(4-aminophenyl)—3,4-diphenylthiophene, bis(4-aminophenyl) ether, and aromatic diacid chlorides in N,N-dimethylacetamide. The polyamides and copolyamides are generally soluble in amide-type solvents. They have glass transition temperatures in the range of 280–325°C and showed no weight loss below 390°C on thermogravimetry curves in both air and nitrogen atmospheres.     

Synthesis and properties of aromatic polyureas from N,N′-bis(trimethylsilyl)-substituted aromatic diamines and aromatic diisocyanates

Silylated aromatic polyureas were synthesized by the polyaddition of N,N′-bis(trimethylsilyl)-substituted aromatic diamines to aromatic diisocyanates in various organic solvents at a temperature ranging from 30 to 100°C. Colorless and transparent films of the silylated polyureas were obtained by casting directly from these solutions in a dry nitrogen atmosphere. The silylated polyureas thermally decomposed at around 200°C and were easily desilylated with alcohol to convert to almost amorphous aromatic polyureas having inherent viscosities of 0.4–1.0 dL/g. The polyureas exhibited better solubility in organic solvents such as N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and dimethyl sulfoxide and had somewhat lower thermal decomposition temperatures (around 300°C) than the polyureas prepared by a conventional method from the parent aromatic diamines and diisocyanates.