Samarium poly(oxamide) polyanions as novel polymeric initiators. One-pot syntheses of graft copolymers

Samarium poly(oxamide) polyanions, formed quantitatively in situ by the reductive coupling polymerization of aromatic diisocyanates with samarium (II) iodide/hexamethylphosphoramide (HMPA) system, were directly used as the polymeric initiators in the graft polymerization with some electrophilic monomers. The graft polymerization of ϵ-caprolactone (CL) with several polyanions derived from bifunctional isocyanates, including tolylene 2,6-diisocyanate, o-tolidine diisocyanate and diphenylmethane diisocyanate, provided the corresponding graft copolymers in one-pot, indicating that the polyanion could work as a new type of reactive polymer. Several factors such as reaction temperature and time and the amount of HMPA and CL affected the behavior of the present polymerization system, and the graft copolymer was obtained quantitatively under the appropriate conditions. The results of the graft polymerizations of tert-butyl methacrylate and methyl methacrylate with the polyanion were also presented. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1381–1387, 1997     

Synthesis,characterization, and chiroptical property of optically active poly(urea-urethane)s

Five new optically active poly(urea-urethane)s were synthesized by solution polyaddition of (1S,2S)-(+)-2-amino-3-methoxy-1-phenyl-1-propanol ( 4 ) with diisocyanates (diphenylmethane-4,4′-diisocyanate, toluene-2,4-diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, m-xylylene diisocyanate) at 80°C for 60 h. In some cases, the reaction mixture transformed into a gel when cooled to room temperature. The reduced viscosities are between 0.14 and 0.63 dL/g depending on the solvents and diisocyanates. Thermal behaviors of these polymers were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The T_g and crystallization temperature (T_c) were in the range of 80–200°C and 220–238°C, respectively. Thermal decomposition started at about 275°C, and the residual weights at 400°C were 15–60% depending on the polymers. The conformation of the polymers in film state was studied by circular dichroism (CD) spectra, by comparison with the corresponding model compounds which were synthesized from 4 and phenyl isocyanate or propyl isocyanate. Polymers derived from aromatic diisocyanates formed as ordered conformation in the film state, while those from aliphatic diisocyanates did not. After packing as chiral stationary phases of high-performance liquid chromatography (HPLC), the polymers showed selective resolution to trans-stilbene oxide and trans-1,2-cyclopentanedicarboxanilide. © 1993 John Wiley & Sons, Inc.     

Preparation and properties of imide‐containing elastic polymers from elastic polyureas and pyromellitic dianhydride

A new approach to obtain imide‐containing elastic polymers (IEPs) via elastic and high‐molecular‐weight polyureas, which were prepared from α‐(4‐aminobenzoyl)‐ω‐[(4‐aminobenzoyl)oxy]‐poly(oxytetramethylene) and the conventional diisocyanates such as tolylene‐2,4‐diisocyanate(2,4‐TDI), tolylene‐2,6‐diisocyanate(2,6‐TDI), and 4,4′‐diphenylmethanediisocyanate (MDI), was investigated. IEP solutions were prepared in high yield by the reaction of the polyureas with pyromellitic dianhydride in N‐methyl‐2‐pyrrolidone (NMP) at 165°C for 3.7–5.2 h. IEPs were obtained by the thermal treatment at 200°C for 4 h in vacuo after NMP was evaporated from the resulting IEP solutions. We assumed a mechanism of the reaction via N‐acylurea from the identification of imide linkage and amid acid group in IEP solutions. NMR and FTIR analyses confirmed that IEPs were segmented polymers composed of imide hard segment and poly(tetramethylene oxide) (PTMO) soft segment. The dynamic mechanical and thermal analyses indicated that the IEPs prepared from 2,6‐TDI and MDI showed a glass‐transition temperature (T_g ) at about −60°C, corresponding to T_g of PTMO segment, and suggested that microphase‐separation between the imide segment and the PTMO segment occured in them. TGA studies indicated the 10% weight‐loss temperatures (T₁₀) under air for IEPs were in the temperature range of 343–374°C. IEPs prepared from 2,6‐TDI and MDI showed excellent tensile properties and good solvent resistance. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 715–723, 2000     

Effect of the diisocyanate on the structure and properties of polyurethane acrylate prepolymers

In this study, we investigated the role of diisocyanate on the properties of polyurethane acrylate (PUA) prepolymers based on polypropylene oxide (M̄_n = 2000 g · mol⁻¹). The diisocyanates studied were isophorone diisocyanate, 4‐4′dicyclohexylmethane diisocyanate, and toluene diisocyanate (pure 2,4‐TDI, pure 2,6‐TDI, and a TDI mixture, TDI_tech). The molecular structure of the diisocyanate had a major role on the course of the polycondensation and, more precisely, on the sequence length distribution of the final prepolymer. Moreover, the structural organization of the prepolymer also strongly depended on the nature of the diisocyanate. Two types of behaviors were particularly emphasized. On the one hand, the PUA synthesized from 2,4‐TDI displayed an enhanced intermixing between soft polyether segments and hard urethane groups, as revealed by the analysis of hydrogen bonding in Fourier transform infrared. Consecutively, the glass transition shifted to higher temperatures for these polymers. On the other hand, strong hard–hard inter‐urethane associations were observed in 2,6‐TDI‐based prepolymers; these led to microphase segregation between polyether chains and urethane groups, as revealed by optical microscopy. This inhomogeneous structure was thought to be responsible for the unusual rheological behavior of these PUA prepolymers. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2750–2768, 2000     

Synthesis and thermal characteristics of phosphorus-containing polyureas and copolyureas based on 1-[(dialkoxyphosphinyl)methyl]-2,4- and -2,6-diaminobenzenes

The reactions of 1-[(dialkoxyphosphinyl)methyl]-2,4- and -2,6-diaminobenzenes (1) with various diisocyanates such as tolylene diisocyanate, methylenebis(4-phenylisocyanate), and hexamethylene-1,6-diisocyanate were studied for the synthesis of phosphorus-containing polyureas. Furthermore, diamines 1 were used as comonomers for preparing fire-resistant copolyureas. In addition, the corresponding common polyureas were synthesized for comparative purposes. All polymers were characterized by elemental analysis, inherent viscosity measurements, infrared (IR) and proton nuclear magnetic resonance (¹H-NMR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The relatively low chemical reactivity of 1 toward diisocyanates was interpreted on the basis of their structural features. The phosphorus-containing polyureas showed a lower molecular weight, a lower polymer decomposition temperature, and a higher char yield than the corresponding common polyureas. Their fire-resistance was evaluated by determining the limiting oxygen index value.     

Synthesis and properties of polyurethanes containing s-triazine rings in the main chain

Eight new diisocyanate monomers containing s-triazine ring have been prepared from the parent diacids via the Curtius rearrangement of the corresponding diacyl azides. The parent diacids were synthesised by the reaction of p- and m-hydroxybenzoic acid with 6-methoxy-2,4-dichloro-s-triazine, 6-phenoxy-2,4-dichloro-s-triazine, 6-phenyl-2,4-dichloro-s-triazine, and 2-diphenylamino-4,6-dichloro-s-triazine respectively. Polyurethanes have been synthesised by solution polymerization of these diisocyanates with ethylene glycol in N,N-dimethylacetamide (DMAC). The resulting polymers were characterized by IR spectroscopy, viscosity measurement, solubility tests, and softening points.     

Monoaryloxo ytterbium(III) chlorides supported by β‐diketiminato ligands as novel initiators for the living ring‐opening polymerization of ε‐caprolactone

Ring‐opening polymerization of ε‐caprolactone (ε‐CL) was carried out using β‐diketiminato‐supported monoaryloxo ytterbium chlorides L¹Yb(OAr)Cl(THF) (1) [L¹ = N,N′‐bis(2,6‐dimethylphenyl)‐2,4‐pentanediiminato, OAr = 2,6‐di‐tert‐butylphenoxo‐], and L²Yb(OAr′)Cl(THF) (2) [L² = N,N′‐bis(2,6‐diisopropylphenyl)‐2,4‐pentanediiminato, OAr′ = 2,6‐di‐tert‐butyl‐4‐methylphenoxo‐], respectively, as single‐component initiator. The influence of reaction conditions, such as polymerization temperature, polymerization time, initiator, and initiator concentration, on the monomer conversion, molecular weight, and molecular weight distribution of the resulting polymers was investigated. Complex 1 was well characterized and its crystal structure was determined. Some features and kinetic behaviors of the CL polymerization initiated by these two complexes were studied. The polymerization rate is first order with respect to monomer. The M_n of the polymer increases linearly with the increase of the polymer yield, while polydispersity remained narrow and unchanged throughout the polymerization in a broad range of temperatures from 0 to 50 °C. The results indicated that the present system has a “living character”. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1147–1152, 2006     

Synthesis and characterization of polyurethanes containing cholesterol and phosphatidylcholine analogous moieties

Several new polyurethanes containing cholesterol and phosphatidylcholine analogous moieties were synthesized by addition polymerization of 2-[bis(2-hydroxyethyl)methylammonio]ethyl 5-cholesten-3β-yl phosphate ( 2 ) with diisocyanates such as hexamethylene diisocyanate (HDI), 2,4-tolylene diisocyanate (TDI), 4,4′-methylenediphenyl diisocyanate (MDI) and m-xylylene diisocyanate (XDI), respectively. They were characterized by their IR and ¹H NMR spectral data and elemental analyses. Preliminary studies suggest that these polyurethanes show the viscosity behavior of common polyelectrolytes.     

Synthesis and property of polyoxazolidone having fluorene moiety by polyaddition of diisocyanate and diepoxide

Polyoxazolidones having fluorenyl group were synthesized by polyaddition of 9,9‐diglycidyl fluorene with various diisocyanates. The polymer from 9,9‐diglycidyl fluorene and methylenediphenyl 4,4′‐diisocyanate was afforded in high yield although polydispersity of the polymer was found relatively broad. The IR spectrum of the obtained polymer showed two absorption in carbonyl region. One of them was assigned to the expected oxazolidone, while the other at 1710 cm^?1 appeared due to a carbonyl group of the isocyanurate moieties produced by cyclotrimerization of isocyanate. It is assumed that the cyclotrimerization would cause the broad polydispersity caused by the branched structure formed by isocyanurate. The polymers obtained with three kinds of diisocyanates (methylenediphenyl 4,4'‐diisocyanate, 1,6‐hexamethylene diisocyanate, 1,4‐phenylene diisocyanate) showed high thermal stability, as their T_d10 was depended on the structure of diisocyanate. All polymers had high transparency in a visible region. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1755–1760     

Synthesis of laterally attached side‐chain liquid‐crystalline polynorbornenes with high mesogen density by ring‐opening metathesis polymerization

(±)‐exo,endo‐5,6‐Bis{[[11′‐[2″,5″‐bis[2‐(3′‐fluoro‐4′‐n‐alkoxyphenyl)ethynyl]phenyl]undecyl]oxy]carbonyl}bicyclo[2.2.1]hept‐2‐ene (n = 1–12) monomers were polymerized by ring‐opening metathesis polymerization in tetrahydrofuran at room temperature with Mo(CHCMe₂Ph)(N‐2,6‐ⁱPr₂Ph)(O^tBu)₂ as the initiator to produce polymers with number‐average degrees of polymerization of 8–37 and relatively narrow polydispersities (polydispersity index = 1.08–1.31). The thermotropic behavior of these materials was independent of the molecular weight and therefore representative of that of a polymer at approximately 15 repeat units. The polymers exhibited an enantiotropic nematic mesophase when n was 2 or greater. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4076–4087, 2006     

Synthesis and characterization of poly(urethane-sulfone)s

Eight poly(urethane-sulfone)s were synthesized from two sulfone-containing diols, 1,3-bis(3-hydroxypropylsulfonyl)propane (Diol-333) and 1,4-bis(3-hydroxypropylsulfonyl)butane (Diol-343), and three diisocyanates, 1,6-hexamethylene diisocyanate (HMDI), 4,4′-diphenylmethane diisocyanate (MDI), and tolylene diisocyanate (TDI, 2,4- 80%; 2,6-20%). As a comparison, eight polyurethanes were also synthesized from two alkanediols, 1,9-nonanediol and 1,10-decanediol, and three diisocyanates. Diol-333 and Diol-343 were prepared by the addition of 1,3-propanedithiol or 1,4-butanedithiol to allyl alcohol and subsequent oxidation of the resulting sulfide-containing diols. The homopoly(urethanesulfone)s from HMDI and MDI are semicrystalline, and are soluble in m-cresol and hot DMF, DMAC, and DMSO. The copoly(urethane-sulfone)s from a 1/1 molar ratio mixture of Diol-333 and Diol-343 with HMDI or MDI have lower crystallinity and better solubility than the corresponding homopoly(urethane-sulfone)s. The poly(urethane-sulfone)s from TDI are amorphous, and are readily soluble in m-cresol, DMF, DMAC, and DMSO at room temperature. Differential scanning calorimetry data showed that poly(urethane-sulfone)s have higher glass transition temperatures and melting points than the corresponding polyurethanes without sulfone groups. The rise in glass transition temperature is 20–25°C while the rise in melting temperature is 46–71°C. © 1994 John Wiley & Sons, Inc.     

Alkylation des «malonyl-α-aminopyridines»

The alkylation of the ‘malonyl-α-aminopyridines’ ( 4 ) gives mixtures of substitution products, mainly the N¹-and O²-alkyl derivatives. The IR., UV. and NMR. spectra are discussed.     

Diisocyanate route as a convenient method for the preparation of novel optically active poly(amide-imide)s based on N-trimellitylimido-S-valine

A new class of optically active poly(amide-imide)s based on an α-amino acid was synthesized via direct polycondensation reaction of different diisocyanates with a chiral diacid monomer. The step-growth polymerization reactions of N-trimellitylimido-S-valine (TISV) (1) with 4,4′-methylene-bis(4-phenylisocyanate) (MDI) (2) was performed under microwave irradiation, as well as solution polymerization under graduate heating and reflux conditions. The optimized polymerization conditions for each method were performed with tolylene-2,4-diisocyanate (TDI) (3), hexamethylene diisocyanate (HDI) (4), and isophorone diisocyanate (IPDI) (5) to produce optically active poly(amide-imide)s via diisocyanate route. The resulting polymers have inherent viscosities in the range of 0.02-1.10 dL/g. Decomposition temperatures for 5% weight loss (T₅) occurred above 300 °C (by TGA) in nitrogen atmospheres. These polymers are optically active, thermally stable and soluble in amide-type solvents. Some structural characterization and physical properties of this new optically active poly(amide-imide)s are reported.     

Lysine‐based functional blocked isocyanates for the preparation of polyurethanes provided with pendant side groups

This article describes a methodology to prepare polyurethanes (PUs), decorated with pendant (bio)functional side groups, by polymerizing (bio)functionalized blocked diisocyanates with polyols. Caprolactam blocked lysine diisocyanate methyl ester (BLDI‐OMe) was prepared in high yields, by reacting the methyl ester of lysine with carbonyl biscaprolactam. In the absence of a catalyst, the polymerization of BLDI‐OMe with polycaprolactone and polytetrahydrofuran resulted in strictly linear PUs due to the high selective reactivity of the blocked isocyanates (BIs). Although the ester appeared to be less reactive, we found hydrolyzing conditions for the ester, without affecting the BIs. The free acid groups were converted into a N‐hydroxysuccinimide (NHS) activated ester, which was a versatile intermediate for further functionalization. After having demonstrated that model amines were able to substitute NHS without effecting the BIs groups, the same chemistry was used to couple biotin, giving a biotin functional caprolactam blocked lysine diisocyanate. The polymerization with polyols afforded the corresponding biotin‐functional PUs. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2036–2049     

Preparation and properties of poly(urethane-imide)s derived from amine-blocked-polyurethane prepolymer and pyromellitic dianhydride

Poly(urethane-imide)s were prepared using amine-blocked-polyurethane (PU) prepolymer and pyromellitic dianhydride. The PU prepolymers were prepared by the reaction of different diols (polypropyleneoxy glycol, polytetramethyleneoxy glycol, polycaprolactonediol and hydroxyl terminated polybutadiene) and different diisocyanates (2,4-tolylene diisocyanate, 1,4-phenelene diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate and 4,4^′-methylenebis(cyclohexyl)isocyanate) and end capped with N-methylaniline. The polymerization was faster with aromatic isocyanates than with aliphatic isocyanates. The effect of imide content on the thermal and mechanical properties was studied. The poly(urethane-imide)s were characterized by FTIR, GPC, TGA and for dynamic and static mechanical properties. Weight average molecular weight (M_w) of the polymers did not vary significantly with change in -NCO/-OH ratio where as number average molecular weight (M_n) increased with increasing -NCO/-OH ratio, correspondingly, the dispersity (PD) decreased. Polymers with higher hard segment content exhibited higher glass transition temperature. The thermal stability of the PU was found to increase significantly by the introduction of imide component.     

Electroninitiated polymerization of bis(trichlorophenoxo)-tetramethylethylene diamine copper(II)

Electroninitiated polymerization of bis(trichlorophenoxo)-N,N,N′,N′-tetramethylethylene diamine copper(II) was achieved in acetonitrile at various peak potentials of the monomer. A constant potential approach was selected in polymerization reactions. Electrolyses were carried out under air, nitrogen, and oxygen atmospheres. Structural analyses of the polymers were done by ¹H-NMR and ¹³C-NMR FT–IR spectroscopy. Molecular weights of the polymers were determined by vapor pressure (isopiestic) method.     

Study on the Alkylation and Sulfonylation of 3-Aryl-1-methyl-1,2,4-triazolin-5-ones

The alkylation and sulfonylation of 3-aryl-1-methyl-1,2,4-triazolin-5-ones (1) were studied with various alkyl halides and sulfonyl chlorides. The alkylation of 1 with methyl iodide and ethyl bromide afforded N-alkylated products, however with methyl 2-bromopropionate afforded O-alkylated products predominantly. The sulfonylation by methanesulfonyl chloride afforded a mixture of N-sulfonylated and O-sulfonylated products, while the sulfonylation by p-toluenesulfonyl chloride afforded mainly O-sulfonylated products.     

Time‐dependent morphology development in segmented polyetherurea copolymers based on aromatic diisocyanates

Time‐dependent morphology development in segmented polyureas obtained by the stoichiometric reactions between amine terminated poly(tetramethylene oxide) (PTMO) and aromatic diisocyanates were investigated. Polyureas were prepared by reacting aminopropyl terminated PTMO oligomer (M_n = 1100 g/mol) and various aromatic diisocyanates, such as 1,4‐phenylene diisocyanate (PPDI), 1,3‐phenylene diisocyanate (MPDI), diphenylmethane diisocyanate (MDI), and tolylene diisocyanate (TDI). Time‐dependent FTIR studies were conducted on thin films cast onto KBr discs, which were annealed at 200 °C for 10 min in an air oven. After removing from the oven, samples were placed into the FTIR spectrometer at room temperature, where time‐dependent spectra were recorded until equilibrium was reached. Time‐dependent peak reorganization in 3500–3100 cm^?1 (N? H region), 1750–1450 cm^?1 (C?O region or amide I and amide II regions), and 1180–1020 cm^?1 (C? O? C) were monitored. Depending on the chemical structure and the symmetry of the diisocyanate, major differences were observed in the time needed to reach an equilibrium morphology in these homologous poly(ether urea) copolymers. Symmetric PPDI‐based polyurea reached equilibrium in about 1 h compared with its asymmetric MPDI‐based counterpart, which needed about 150 h. Microphase development of the MPDI urea was also characterized by AFM, which gave similar results. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 471–483, 2009     

Synthesis and characterization of urethane polymers containing 2,2′-biimidazole

A heterocyclic nitrogen-containing system having substituent primary diol function, i.e., 1,1′-dihydroxethyl-2,2′-biimidazole ( I ), has been prepared and used to synthesize a series of new polyurethanes based on aromatic diisocyanates (TDI, MDI). Variation of solution polymerization parameters permitted the isolation and infrared, NMR, molecular weight, and thermal characterization of polymeric materials. Isolated polymers exhibit a linear structure and have T_g (150–170°C) and thermal stability (205–250°C for 20% weight loss) properties comparable to other typical urethane polymers. Zn²⁺ complexation was indicated by shifts in the imidazole ringmode infrared vibrational bands at 917 and 1133 cm^?1 to higher frequencies.     

Synthesis of nylon‐6 triblock copolymers with bifunctional polymeric activators

ABA‐type copolymers were synthesized by the anionic polymerization of hexanelactam with the sodium salt of hexanelactam as an initiator and amino‐terminated polytetrahydrofuran telechelic functionalized with diisocyanates. Two types of diisocyanates, hexamethylene diisocyanate (1,6‐diisocyanatohexane) and isophorone diisocyanate (IF; 5‐isocyanato‐1‐isocyanatomethyl‐1,3,3‐trimethylcyclohexane), were used as precursors for polymeric activators (PACs). IF was used for the first time. It was proven that the PACs were incorporated as soft, flexible midblocks in the chains of hard nylon‐6 segments. The polymers were isolated and characterized with various spectroscopic techniques. The effects of the central PAC block (according to the type, molecular weight, and content) and the polymerization conditions on the kinetics, activation energies, molecular weights, and structures of the triblock copolymers were investigated. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4154–4164, 2000