Solid-State Polymerization of 4-(4-Dimethylaminophenyl)-urazole with Diisocyanates

In the present study, the solid-state thermal polymerization of 4-(4-dimethylaminophenyl)-1,2,4-triazolidine-3,5-dione (DAPTD) with diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate and toluylene-2,4-diisocyanate as a new method for synthesis of polyureas are described. The influence of reaction parameters, such as presence of catalyst in the starting material and ratio of DAPTD to diisocyanate were investigated. Polycondensation was successfully preceded without any solvent, which is used in conventional method. The resulting polyureas were obtained in high yields with inherent viscosities ranging from 0.14 to 0.25 dL/g. This method was also compared with two other polycondensation methods for the polymerization reactions which were reported before: conventional solution method and a method using tetrabutylammonium bromide as a molten ionic liquid media.     

Step-Growth Polymerization of 4-(1-Naphthyl)-1,2,4-triazolidine-3,5-dione with Diisocyanates

Summary We have synthesized 4-(1-naphthyl)-1,2,4-triazolidine-3,5-dione (4-NTD) in high yield and purity from 1-naphthyl isocyanate and used it as a new monomer for polymer synthesis. A series of novel naphthalene-containing polyureas have been successfully prepared from 4-NTD with hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI) and toluene-2,4-diisocyanate (TDI) in N,N-dimethylacetamide (DMAc) or N-methylpyrrolidone (NMP) solution in the presence of pyridine, triethylamine or dibutyltin dilurate as catalysts. Some physical properties and structural characterization of these novel polyureas are reported. Fluorimetric studies of the new monomer, model compound as well as polymers were also investigated.     

Microwave‐assisted rapid polycondensation reaction of 4‐(4′‐acetamidophenyl)‐1,2,4‐triazolidine‐3,5‐dione with diisocyanates

4‐(4′‐Aminophenyl)‐1,2,4‐triazolidine‐3,5‐dione was reacted with 1 mol of acetyl chloride in dry N,N‐dimethylacetamide (DMAc) at ?15°C and 4‐(4′‐acetamidophenyl)‐1,2,4‐triazolidine‐3,5‐dione [4‐(4′‐acetanilido)‐1,2,4‐triazolidine‐3,5‐dione] (APTD) was obtained in high yield. The reaction of the APTD monomer with excess n‐isopropylisocyanate was performed at room temperature in DMAc solution. The resulting bis‐urea derivative was obtained in high yield and was finally used as a model for the polymerization reaction. The step‐growth polymerization reactions of monomer APTD with hexamethylene diisocyanate, isophorone diisocyanate, and tolylene‐2,4‐diisocyanate were performed under microwave irradiation and solution polymerization in the presence of pyridine, triethylamine, or dibutyltin dilaurate as a catalyst. Polycondensation proceeded rapidly, compared with conventional solution polycondensation; it was almost completed within 8 min. The resulting novel polyureas had an inherent viscosity in the range of 0.07–0.17 dL/g in dimethylformamide or sulfuric acid at 25°C. These polyureas were characterized by IR, ¹H‐NMR, elemental analysis, and thermogravimetric analysis. The physical properties and structural characterization of these novel polyureas are reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2103–2113, 2004     

Synthesis of aliphatic polyamides containing 4-phenylurazole linkages

4-Phenylurazole (1) was reacted with excess acetyl chloride in N,N-dimethylacetamide (DMAc) solution at room temperature. The reaction occurred in quantitative yield with acetylation of both of the N H bonds of the urazole group. This compound was characterized by IR, ¹ H NMR and elemental analysis, and was used as a model compound for the polymerization reaction. Solution polymerization of monomer (1) with adipoyl chloride (AC) and suberoyl chloride (SC) was performed in DMAc and chloroform in the presence of pyridine, and lead to the formation of a novel aliphatic polyamide with an inherent viscosity in the range of 0.108–0.396 dl g⁻¹. When interfacial polymerization of monomer (1) with suberoyl chloride was performed in DMAc/cyclohexane, a lower viscosity resulted. The resulting polymers are soluble in most organic solvents. Some structural characterization and physical properties of these novel polymers are reported. © 1999 Society of Chemical Industry     

Preparation and characterization of new photoactive polyamides containing 4‐(4‐dimethylaminophenyl)urazole units

4‐(4‐dimethylaminophenyl)‐1,2,4‐triazolidine‐3,5‐dione ( DAPTD ) was prepared from 4‐dimethylaminobenzoic acid in five steps. The compound DAPTD was reacted with excess acetyl chloride in N,N‐dimethylacetamide (DMAc) solution and gave 1,2‐bisacetyl‐4‐[4‐(dimethylaminophenyl)]‐1,2,4‐triazolidine‐3,5‐dione as a model compound. Solution polycondensation reactions of monomer with succinyl chloride (SucC), suberoyl chloride (SubC), and sebacoyl chloride (SebC) were performed under conventional solution polymerization techniques in the presence of triethylamine and pyridine as a catalyst in N‐methylpyrrolidone (NMP) and led to the formation of novel aliphatic polyamides. These novel polyamides have inherent viscosities in the range of 0.09–0.21 dL/g in N,N‐dimethylformamide (DMF) at 25°C. Fluorimetric studies of the model compound as well as polymers were performed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 947–954, 2007     

Synthesis of novel azo‐containing polyureas derived from 4‐[4′‐(2‐hydroxy‐1‐naphthylazo)phenyl]‐1,2,4‐triazolidine‐3,5‐dione

4‐[4′‐(2‐Hydroxy‐1‐naphthylazo)phenyl]‐1,2,4‐triazolidine‐3,5‐dione ( HNAPTD ) ( 1 ) has been reacted with excess amount of n‐propylisocyanate in DMF (N,N‐dimethylformamide) solution at room temperature. The reaction proceeded with high yield, and involved reaction of both N? H of the urazole group. The resulting bis‐urea derivative 2 was characterized by IR, ¹H‐NMR, elemental analysis, UV‐Vis spectra, and it was finally used as a model compound for the polymerization reaction. Solution polycondensation reactions of monomer 1 with Hexamethylene diisocyanate ( HMDI ) and isophorone diisocyanate ( IPDI ) were performed in DMF in the presence of pyridine as a catalyst and lead to the formation of novel aliphatic azo‐containing polyurea dyes, which are soluble in polar solvents. The polymerization reaction with tolylene‐2,4‐diisocyanate ( TDI ) gave novel aromatic polyurea dye, which is insoluble in most organic solvents. These novel polyureas have inherent viscosities in a range of 0.15–0.22 g dL^?1 in DMF at 25°C. Some structural characterization and physical properties of these novel polymers are reported. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3177–3183, 2001     

Synthesis and characterization of new polyureas based on 4‐(4′‐aminophenyl)urazole and various diisocyanates

4‐(4′‐Aminophenyl)urazole (AmPU) was prepared from 4‐nitrobenzoic acid in six steps. The reaction of monomer AmPU with n‐isopropylisocyanate was performed in N,N‐dimethylacetamide solutions at different ratios, and the resulting disubstituted and trisubstituted urea derivatives were obtained in high yields and were finally used as models for polymerization reactions. The step‐growth polymerization reactions of AmPU with hexamethylene diisocyanate, isophorone diisocyanate, and toluene‐2,4‐diisocyanate were performed in N‐methylpyrrolidone solutions in the presence of pyridine as a catalyst. The resulting novel polyureas had inherent viscosities of 0.11–0.18 dL/g in dimethylformamide at 25°C. These polyureas were characterized with IR, ¹H‐NMR, elemental analysis, and thermogravimetric analysis. Some physical properties and structural characterization of these novel polyureas are reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2692–2700, 2003     

Chromophoric poly(urea‐urethane)s with pendent 3‐hydroxynaphthalene group: Synthesis and characterization

The reaction of 4‐(3‐hydroxynaphthalene)‐1,2,4‐triazolidine‐3,5‐dione ( 3HNTD ) with n‐propylisocyanate was performed at different molar ratios. The resulting monosubstituted urea and disubstituted urea‐urethane derivatives were obtained in high yields and were used as model compounds for polymerization reactions. 3HNTD as a monomer was used in the preparation of heterocyclic poly(urea‐urethane)s to produce photoactive polymers, by polycondensation with different diisocyanates in N,N‐dimethylacetamide (DMAc) solution. Chromophoric heterocyclic polymers containing naphthalene group, obtained in quantitative yields, possessed inherent viscosities in the range of 0.14–0.38 dL/g. The resulting poly(urea‐urethane)s is insoluble in most organic solvents, but easily soluble in polar solvents such as dimethyl sulfoxide (DMSO), DMAc, and N‐methylpyrrolidone (NMP). The polymers were characterized by IR, ¹H‐NMR, elemental analysis, and TGA. Fluorimetric and UV–vis studies of the monomer as well as polymers were performed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of novel photoactive heterocyclic polyimides containing naphthalene moieties via cycloaddition reactions

1‐Naphthylacetic acid (1) was reacted with thionyl chloride and 1‐naphthyl‐ acetyl chloride (2) was obtained in a quantitative yield. The reaction of this acid chloride (2) with isoeugenol (3) was performed in chloroform and a novel isoeugenol ester derivative (4) as a monomer was obtained in a high yield. The compound (4) was characterized by ¹H‐NMR, IR, mass, and elemental analyses and then was used for the preparation of a model compound (6) and polymerization reactions. 4‐Phenyl‐1,2,4‐triazoline‐3,5‐dione (PhTD) (5) was allowed to react with compound (4). The reaction is very fast and gives only one double adduct (6) via Diels–Alder and ene pathways in an excellent yield. The polymerization reactions of the novel monomer (4) with bistriazolinediones [bis‐(p‐3,5‐dioxo‐1,2,4‐triazolin‐4‐ylphenyl)methane (7) and 1,6‐bis‐(3,5‐dioxo‐1,2,4‐triazolin‐4‐yl)hexane] (8) were carried out in N,N‐dimethylacetamide (DMAc) at room temperature. The reactions are exothermic and fast and gave novel heterocyclic polyimides containing a naphthalenic pendant group (9) and (10) via repetitive Diels–Alder‐ene polyaddition reactions. Stereochemical analysis of the model compound and fluorimetric studies of the model compound as well as polymers were done conclusively. Excimer formation of the polymers and its effect on fluorescence emission were investigated and some structural characterization and physical properties of these novel heterocyclic polyimides are reported. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 527–536, 2000     

Polymerization of 4‐(4′‐N‐1,8‐naphthalimidophenyl)‐1,2,4‐triazolidine‐3,5‐dione with diisocyanates

4‐(4′‐Aminophenyl)‐1,2,4‐triazolidine‐3,5‐dione ( 1 ) was reacted with 1,8‐naphthalic anhydride ( 2 ) in a mixture of acetic acid and pyridine (3 : 2) under refluxing temperature and gave 4‐(4′‐N‐1,8‐naphthalimidophenyl)‐1,2,4‐triazolidine‐3,5‐dione ( NIPTD ) ( 3 ) in high yield and purity. The compound NIPTD was reacted with excess n‐propylisocyanate in N,N‐dimethylacetamide solution and gave 1‐(n‐propylamidocarbonyl)‐4‐[4′‐(1,8‐naphthalimidophenyl)]‐1,2,4‐triazolidine‐3,5‐dione ( 4 ) and 1,2‐bis(n‐propylamidocarbonyl)‐4‐[4′‐(1,8‐naphthalimidophenyl)]‐1,2,4‐ triazolidine‐3,5‐dione ( 5 ) as model compounds. Solution polycondensation reactions of monomer 3 with hexamethylene diisocyanate ( HMDI ), isophorone diisocyanate ( IPDI ), and tolylene‐2,4‐diisocyanate ( TDI ) were performed under microwave irradiation and conventional solution polymerization techniques in different solvents and in the presence of different catalysts, which led to the formation of novel aliphatic‐aromatic polyureas. The polycondensation proceeded rapidly, compared with conventional solution polycondensation, and was almost completed within 8 min. These novel polyureas have inherent viscosities in a range of 0.06–0.20 dL g^?1 in conc. H₂SO₄ or DMF at 25°C. Some structural characterization and physical properties of these novel polymers are reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2861–2869, 2003     

Synthesis and characterization of new polyureas derived from 4‐(4′‐Methoxyphenyl)urazole

4‐(4′‐Methoxyphenyl)urazole (MPU) was prepared from 4‐methoxybenzoic acid in five steps. The reaction of monomer MPU with n‐isopropylisocyanate was performed at room temperature in N,N‐dimethylformamide solution, and the resulting bis‐urea derivative was obtained in high yield and was finally used as a model for polymerization reaction. The step‐growth polymerization reactions of monomer MPU with hexamethylene diioscyanate, isophorone diioscyanate, and toluene‐2,4‐diioscyanate were performed in N,N‐dimethylacetamide solution in the presence of pyridine as a catalyst. The resulting novel polyureas have an inherent viscosity (η_inh) in a range of 0.07–0.21 dL/g in DMF and sulfuric acid at 25°C. These polyureas were characterized by IR, ¹H‐NMR, elemental analysis, and TGA. Some physical properties and structural characterization of these novel polyureas are reported. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1141–1146, 2002     

Synthesis and characterization of a rigid poly(amide hydrazide): effect of some reaction parameters on the viscosity of the polymer formed

A wholly aromatic all-para oriented poly(amide hydrazide) has been synthesized from N,N′-bis(4-aminobenzoyl) hydrazine (BABH) and terephthaloyl chloride (TC) by low temperature solution polycondensation. The polymer was characterized by elemental analyses, IR spectroscopy, solubility, viscosity and density measurements. The effect of various factors controlling the polymerization reaction (concentration of monomer and electrolyte (LiCl) in the reaction medium, nature of the medium and temperature at the initial stage of polymerization) on polymer viscosity was studied. To prepare a polymer of high viscosity, the optimum conditions were found to be, monomer concentration 0·25moll^-1, LiCl concentration (in DMAc) 1% (w/v), with use of N-methyl pyrrolidone (NMP) as polymerization medium. The thermal behaviour of the polymer was studied in air and nitrogen by TGA and DSC. ©1997 SCI     

A novel and green method for polycondensation reaction of 4-substituted phenylurazoles with different diisocyanates under solvent-free conditions

In this investigation, a new method for step-growth polymerization reactions of 4-phenylurazole ( PHU ) and 4-(4-methoxyphenyl)urazole ( MPU ) with various diisocyanates were developed under solvent-free conditions. The reaction of these monomers with hexamethylene diisocyanate ( HMDI ), isophorone diisocyanate ( IPDI ), and tolulyene-2,4-diisocyanate ( TDI ) were performed in the presence or absence of dibutyltin dilaurate ( DBTDL ) as a catalyst. The results of polymerization revealed that DBTDL did not have considerable effect on the polymerization process. The resulting polyureas showed good yields and moderate inherent viscosities ranging of 0.17–0.30 dL/g in N,N-dimethylformamide (DMF) at 25°C. They are soluble in most polar organic solvents. All of the above polymers were characterized by ¹H-NMR, FTIR spectroscopy, and thermogravimetric analysis (TGA). This method was compared with the polymerization reaction in N,N-dimethylacetamide as a solvent via solution polymerization. Under solvent-free conditions, higher yields and inherent viscosities were obtained. In addition, in this method we do not need to use any solvents and the polymerization reaction can be classified as a green and environmentally friendly method. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Novel Optically Active Poly(amide-imide)s Derived from N-Trimellitylimido-L-Isoleucine and Different Diisocyanates

Summary  A new class of optically active poly(amide-imide)s was synthesized via direct solution polycondensation of different aliphatic and aromatic diisocyanates with a chiral diacid monomer. The polymerization of N-trimellitylimido-L-isoleucine (TMIIL)(1) as an aromatic-aliphatic diacid monomer with 4,4’-methylenebis(phenyl isocyanate) (MDI)(2) was carried out by graduate heating as well as refluxing method in the presence of pyridine (Py), dibutyltin dilaurate (DBTDL), triethylamine (TEA) as a catalyst and without catalyst, respectively. In these solution polycondensations we used amino acids as chiral inducing agents. The optimized polymerization conditions of MDI were used for the polymerization of isophorone diisocyanate (IPDI)(3), tolylene-2,4-diisocyanate (TDI)(4), and hexamethylene diisocyanate (HDI)(5). The resulting polymers have inherent viscosities in a range of 0.17–0.48 dL/g. These polymers are optically active, thermally stable and soluble in amide type solvents.     

Microwave‐assisted and classical heating polycondensation reaction of bis(p‐amido benzoic acid)‐N‐trimellitylimido‐L‐leucine with diisocyanates as a new method for preparation of optically active poly(amide imide)s

A new class of optically active poly(amide imide)s were synthesized via direct polycondensation reaction of diisocyanates with a chiral diacid monomer. The step‐growth polymerization reactions of monomer bis(p‐amido benzoic acid)‐N‐trimellitylimido‐L‐leucine (BPABTL) (5) as a diacid monomer with 4,4′‐methylene bis(4‐phenylisocyanate) (MDI) (6) was performed under microwave irradiation, solution polymerization under gradual heating and reflux condition in the presence of pyridine (Py), dibuthyltin dilurate (DBTDL), and triethylamine (TEA) as a catalyst and without a catalyst, respectively. The optimized polymerization conditions according to solvent and catalyst for each method were performed with tolylene‐2,4‐diisocyanate (TDI) (7), hexamethylene diisocyanate (HDI) (8), and isophorone diisocyanate (IPDI) (9) to produce optically active poly(amide imide)s by the diisocyanate route. The resulting polymers have inherent viscosities in the range of 0.09–1.10 dL/g. These polymers are optically active, thermally stable, and soluble in amide type solvents. All of the above polymers were fully characterized by IR spectroscopy, ¹H NMR spectroscopy, elemental analyses, specific rotation, and thermal analyses methods. Some structural characterization and physical properties of this new optically active poly(amide imide)s are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1647–1659, 2004     

Synthesis and optical properties of poly(phenylenevinylene) modified with 3,4-bis(phenylene)-3-cyclobutene-1,2-dione moiety

Summary A new class of soluble poly(p-phenylenevinylene)-modified conjugated polymers with a simple aromatic unit of 3,4-bis(phenylene)-3-cyclobutene-1,2-dione in the main chain was synthesized by the dehalogenation polycondensation and the Heck reaction. The monomer and the polymers were characterized by FT-IR, ¹H-NMR, UV-visible, Elemental Anaylsis, TGA and DSC. The resultant polymers were obtained as yellow powder, formed the brittle film from the DMAc solution. These polymers were soluble in polar aprotic solvents, such as NMP, DMAc, DMF and DMSO. The present polymers show absorption bands in the range of 286∼325nm, corresponding to the π-π^* electronic transition of the conjugated polymer backbones. The photoluminescence spectrum of the polymer 1 shows a peak at 471nm while the polymer 2 has the peak at 522nm with DMAc solution, in the blue emission region. Received: 21 January 1999/Revised version: 2 April 1999/Accepted: 5 April 1999     

Oxidative coupling polymerization of racemic 3,3’-dihydroxy-2,2’-dimethoxy-1,1’-binaphthalene with copper(II)-(-)-sparteine complex

Summary The oxidative coupling polymerization of racemic 3,3’-dihydroxy-2,2’-dimethoxy-1,1’-binaphthalene with copper(II) chloride-(-)-sparteine [(-)Sp] in methanol at room temperature was carried out and the enantiomer-selectivity during the polymerization was examined. The (R)-monomer preferentially reacted, and the purity of the unreacted monomer reached 80%ee (S) after 15 h, while that of the polymerized monomer gradually decreased from 26%ee (R) as a function of the polymerization. The ratio of the rate constants of both enantiomers, s=k_R/k_S, was determined to be 2.3. The model coupling reaction of the mono-benzylated (R)-monomer with CuCl₂-(-)Sp showed that the R-configuration with respect to the carbon-carbon bonds between the monomer units was selectively constructed during the polymerization.     

Synthesis and characterization of novel optically active and flame‐retardant heterocyclic polyimides

Tetrachlorophthalic anhydride (1) was reacted with L ‐leucine (2) in toluene solution at refluxing temperature in the presence of triethylamine and the resulting imide‐acid (4) was obtained in quantitative yield. The compound (4) was converted to the N‐(tetrachlorophthaloyl)‐L ‐leucine acid chloride (5) by reaction with thionyl chloride. The reaction of this acid chloride (5) with isoeugenol (6) was carried out in chloroform and novel optically active isoeugenol ester derivative (7) as a chiral monomer was obtained in high yield. The compound (7) was characterized by ¹H‐NMR, IR, Mass and elemental analysis, and then was used for the preparation of model compound (10) and polymerization reactions. 4‐Phenyl‐1,2,4‐triazoline‐3,5‐dione, PhTD (8) was allowed to react with compound (7). The reaction is very fast, and gives only one diastereomer of (10) via Diels–Alder and ene pathways in excellent yield. The polymerization reactions of novel monomer (7) with bistriazolinediones [bis‐(p‐3,5‐dioxo‐1,2,4‐triazolin‐4‐ylphenyl)methane (11) and 1,6‐bis‐(3,5‐dioxo‐1,2,4‐triazolin‐4‐yl)hexane] (12) were carried out in N,N‐dimethylacetamide (DMAc) at room temperature. The reactions are exothermic, fast, and give novel optically active polymers (13) and (14) via repetitive Diels–Alder‐ene polyaddition reactions. The resulting polymers are optically active, thermally stable, and flame resistant. All of the above compounds were fully characterized by IR, ¹H‐NMR, elemental analysis, and specific rotation. Some structural characterization and physical properties of these novel heterocyclic polyimides are reported. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 240–248, 2000     

Stabilization of the living end in the anionic polymerization of 2-(trimethylsiloxy)ethyl methacrylate

Summary In an anionic polymerization of 2-(trimethylsiloxy)ethyl methacrylate (Pro HEMA), the loading rate of the monomer was found to influence the polymerization. When the monomer loading was run quickly via a dropping funnel, the ProHEMA polymerization occurred quantitatively to form poly(ProHEMA) with a narrow molecular weight distribution (MWD). Based on the results, we propose a mechanism in which monomer molecules surrounding the propagating species take part, viz, the surrounding monomer molecules prevent a possible termination reaction. In the presence of LiC1 for ProHEMA polymerization, a polymer with a rather narrower MWD was obtained.     

Highly diastereoselective synthesis of novel polymers via tandem Diels–Alder–ene reactions

Cis -9,10-dihydro-9,10-ethanoanthracene-11-12-dicarboxylic acid anhydride (1) was converted into its amic acid derivative by reaction with L -leucine. The cyclization reaction was carried out in situ using triethylamine to give the succinic imide-acid derivative (2). Compound (2) was converted to the acid chloride (3) by reaction with thionyl chloride. The reaction of acid chloride (3) with isoeugenol (4) was carried out in chloroform and a novel optically active isoeugenol ester derivative (5) was obtained in high yield. 4-Phenyl-1,2,4-triazoline-3,5-dione (PhTD) (6) was allowed to react with compound (5). The reaction is very fast and gives only one diastereoisomer of (7) via Diels–Alder and ene pathways in quantitative yield. Compound (7) was characterized by ¹H NMR, IR, specific rotation and elemental analysis, and was used as a model for the polymerization reactions. The polymerization reactions of compound (5) with bis-triazolinediones (8), (9) were performed in N,N-dimethylacetamide (DMAc) at room temperature. The reactions are exothermic and fast, and give novel optically active polymers. Some physical properties and structural characterizations of these new polymers have been studied, and are reported. © 1999 Society of Chemical Industry