Synthesis of head‐to‐tail polyurethanes from nonsymmetric diisocyanate and ethylene glycol with organotin catalysts

An ordered head‐to‐tail (HT) polyurethane was successfully prepared by the polyaddition reaction of p‐isocyanatobenzyl isocyanate with ethylene glycol with dibutyltin dilaurate as a catalyst. Furthermore, the HT regularity of polyurethane was improved to 83% with 1,1,3,3‐tetraphenyl‐1,3‐dichlorodistannoxane. The polymerization was conducted in N,N‐dimethylformamide at 30 °C with both monomers mixed at once. The microstructure of the polymer was investigated by ¹H and ¹³C NMR spectroscopy, and the polymer obtained by the polyaddition reaction had the expected HT linkages. The constitutional regularity of the polymers influenced the thermal properties and crystallinity. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 416–429, 2001     

Conjugated vinyl derivatives of chitooligosaccharide: Synthesis and characterization

The introduction of a conjugated vinyl group to chitooligosaccharide (COS) has been easily accomplished by the coupling of glycidyl methacrylate (GMA) to COS in aqueous solution without an additional catalyst. Depolymerization of chitosan was carried out by deaminative cleavage using sodium nitrite. The average degree of polymerization of COS could be controlled by varying the molar ratio of sodium nitrite and the amino group of chitosan. The degree of substitution (percentage), as determined by ¹H NMR, of GMA to COS increased up to 60% at a reaction time of 48 h. The structure of products (COS‐GMAs) were identified by Fourier transform infrared spectroscopy, ¹H NMR, and ¹³C NMR. The resulting COS‐GMAs were readily soluble in neutral water, like the original COS, and exhibited an excellent antimicrobial activity. The reactivity of COS‐GMA was investigated by the reaction with poly(vinyl alcohol) (PVA). The reaction products were found to have a lower crystallinity than PVA because of the introduction of the COS‐GMA units. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 880–887, 2001     

Melt modification of poly(styrene‐co‐maleic anhydride) with alcohols in the presence of 1,3‐oxazolines

Various copolyesteramides were prepared by melt compounding at 220 °C involving reaction of poly(styrene‐co‐maleic anhydride), SMA, with 6, 17, and 28 wt % maleic anhydride content, and 1‐dodecanol, C12OH, in the presence of 2‐undecyl‐1,3‐oxazoline, C11OXA. Copolymer architectures were examined by means of ¹H NMR, FTIR, DSC, and TGA using model compounds prepared via solution reactions. While conversion of anhydride with alcohol was poor due to the thermodynamically favored anhydride ring formation, very high conversions were achieved when stoichiometric amounts of C11OXA were added. According to spectroscopic studies esteramide groups resulted from reaction of oxazoline with carboxylic acid intermediate. In the absence of alcohol, C11OXA reacted with anhydride to produce esterimides. Effective attachment of flexible n‐alkyl side chains via simultaneous reaction of C12OH and C11OXA resulted in lower glass‐transition temperatures of copolyesteramides. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1222–1231, 2000     

Dihydrophilic block copolymers with ionic and nonionic blocks. I. Poly(ethylene oxide)‐b‐polyglycidol with OP(O)(OH)2, COOH,or SO3H functions: Synthesis and influence for CaCO3 crystallization

Dihydrophilic block copolymers of poly(ethylene oxide)‐b‐polyglycidol were prepared and polyglycidol blocks converted into ionic blocks containing  OP(O)(OH)₂,  COOH, or  SO₃H groups. Although phosphorylation of polyhydroxy compounds with POCl₃ usually leads to insoluble products, phosphorylation of poly(ethylene oxide)‐b‐polyglycidol using a POCl₃/ OH ratio equal to 1/1 gave soluble products, predominantly monoester of phosphoric acid (after hydrolysis) (provided that the reaction was conducted in triethyl phosphate as solvent). All copolymers were characterized by ¹H NMR, ¹³C NMR, and/or ³¹P NMR spectra for confirming their structure. The degree of substitution was determined from quantitative ¹³C NMR spectroscopy (inverted‐gate decoupling‐acquisition mode). Preliminary results indicate that from these three groups of block copolymers the phosphoric acid esters are the most effective ones at least in controlling the growth of CaCO₃ crystals in aqueous solution. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 955–963, 2001     

Synthesis and properties of vinyl‐terminated and silicon‐containing polysulfones and polyketones

4‐Fluorophenylsulfonylphenyl‐terminated polysulfone and 4‐fluorobenzoylphenyl ketone were prepared with bisphenol A and an excess of bis‐(4‐fluorophenyl)sulfone or 4,4′‐difluorobenzophenone, respectively, at 160 °C using potassium carbonate in N,N‐dimethylacetamide. The resulting polymers were reacted with 4‐hydroxystyrene to synthesize vinyl‐terminated polysulfones and ketones. The silicon‐containing polysulfones and ketones were prepared from the vinyl‐terminated polymer precursor and various H‐functional silanes or siloxanes. The synthesis of silicon‐containing polymers was achieved by hydrosilation with a rhodium catalyst. It was shown that the hydrosilation reaction proceeds with 55:45 chemoselectivity. The resulting polymers were investigated by ¹H NMR spectroscopy, DSC, and thermogravimetric analysis. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2937–2942, 2001     

Glycopolymers resulting from ethylene–vinyl alcohol copolymers: Synthetic approach,characterization, and interactions with lectins

Ethylene–vinyl alcohol copolymers, EVOH, with two different vinyl alcohol compositions have been functionalized with carboxylic acid groups by reaction with phthalic anhydride. Later on, the coupling reaction of three aminosaccharides (D ‐(+)‐glucosamine, D ‐(+)‐galactosamine, and D ‐(+)‐mannosamine) to functionalized EVOH copolymers has been carried out in dimethyl sulfoxide at 70 °C to achieve water soluble glycopolymers. The structure of the resulting functionalized copolymers and the new glycopolymers was confirmed by ¹H and ¹³C NMR. Likewise, the thermal behavior of glycopolymers has been performed by differential scanning calorimetry and thermal gravimetric analysis. In addition, their affinity to lectins, specifically to Concanavalin A and Ricinus Communis Agglutinin, has been evaluated. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7238–7248, 2008     

An efficient route for the synthesis of hyperbranched polymers and dendritic building blocks based on urea linkages

A highly efficient synthetic route, based on the quantitative reaction between amine and isocyanate functionalities, was used successfully for the synthesis of hyperbranched polymers and dendritic building blocks based on urea linkages. The thermal decomposition of 3,5‐diamino benzoyl azide or 5‐amino isophthaloyl azide generated in situ the corresponding phenyl isocyanates, which were then polymerized to give wholly aromatic hyperbranched polyureas. Hyperbranched polyurea with amine chain ends was soluble in common organic solvents. The degree of branching, as calculated with ¹H NMR, was 0.55. Diethyl 5‐amino isophthalate and Boc‐protected 5‐amino isophthaloyl azide were used for the successful stepwise synthesis of dendritic wedges based on urea linkages. The thermal generation of the isocyanate functionality with gaseous nitrogen as the side product and its quantitative reaction with amine groups were the salient features of this convergent synthesis. This eliminated the use of chromatographic purification, an inherent part of other convergent growth approaches, and made it a very efficient synthetic route for the synthesis of dendritic wedges. The products were characterized by ¹H NMR, ¹³C NMR, and electron spray mass spectroscopy (ESMS) techniques. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1295–1304, 2001     

Synthesis and characterization of stereoregular AABB‐type polymannaramides

The condensation of D ‐mannaro‐1,4:6,3‐dilactone ( 2 ) with even‐numbered alkylenediamines (C₂, C₆–C₁₂) in a methanol solution and in the presence of triethylamine afforded polymannaramides 3 – 7 , which were isolated directly as white solids with various hydrophobic–hydrophilic characters. Because all the stereocenters in 2 possessed an S configuration, the random polymerization led to optically active, stereoregular polyhydroxypolyamides. The polymers were characterized by elemental analysis and IR, ¹H NMR, and ¹³C NMR spectroscopy. Their number‐average molecular weights were estimated by ¹H NMR spectral integration analysis. Thermal and powder X‐ray diffraction studies revealed that compounds 3 – 7 were poorly crystalline. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1024–1030, 2001     

Microstructure of glycidylmethacrylate/vinyl acetate copolymers by two‐dimensional nuclear magnetic resonance spectroscopy

Glycidylmethacrylate/vinyl acetate copolymers were prepared by solution polymerization with benzene as a solvent and benzoyl peroxide as an initiator. Copolymer compositions were determined from ¹H NMR spectra, and comonomer reactivity ratios were determined by the Kelen–Tudos (KT) method and the nonlinear least‐squares error‐in‐variable method (EVM). The reactivity ratios obtained from KT and EVM were r_G = 37.4 ± 12.0 and r_V = 0.036 ± 0.019 and r_G = 35.2 and r_V = 0.03, respectively. Complete spectral assignments of ¹³C and ¹H NMR spectra were done with the help of distortionless enhancement by polarization transfer and two‐dimensional ¹³C–¹H heteronuclear single quantum coherence and total correlation spectroscopy. The methyl, methine, and methylene carbon resonance showed both stereochemical and compositional sensitivity. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4051–4060, 2001     

Preparation,properties, and antibacterial behavior of a novel cellulose derivative containing lactam groups

Lactam groups were introduced onto the backbone of hydroxyethyl cellulose (HEC) to modify properties, such as solubility in organic solvents and solution viscosity and to introduce possible antibacterial activity. Functionalization was achieved using 1‐(hydroxymethyl)‐2‐pyrrolidinone (HMP), and the functionalization reactions were investigated using NMR spectroscopy. The covalent attachment between HEC and HMP was confirmed using ¹H‐¹³C correlated NMR experiments. Degrees of functionalization were calculated using integrated ¹³C NMR spectra, with values of up to 0.9 being demonstrated on the primary alcohol functionality of HEC. The functionalized HECs showed markedly different properties to unfunctionalized HEC, including the ability to swell considerably in water. Functionalized HEC displayed increased thermal stability and reduced solution viscosity compared with unfunctionalized HEC. Moreover, functionalization altered the bacterial adhesion characteristics compared with unfunctionalized HEC. © 2014 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 68–78     

Molecular motion in nanocomposites of poly(ethylene oxide) and montmorillonite

Motion of chains of poly(ethylene oxide) within the interlayer spacing of 2:1 phyllosilicate/montmorillonite was studied with ¹H and ¹³C NMR spectroscopy. Measurements of the ¹H NMR line widths and relaxation times across a large temperature range were used to determine the effect of bulk thermal transitions on polymer chain motion within the nanocomposites. The results were consistent with previous reports of low apparent activation energies of motion. Details of the frequency and geometry of motion were obtained from a comparison of the ¹³C cross‐polarity/magic‐angle spinning spectra and relaxation times of the nanocomposite with those of the pure polymer. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1678–1685, 2001     

Solvent‐free and nonisocyanate melt transurethane reaction for aliphatic polyurethanes and mechanistic aspects

A novel melt transurethane polycondensation route for polyurethanes under solvent‐free and nonisocyanate condition was developed for soluble and thermally stable aliphatic or aromatic polyurethanes. The new transurethane process was investigated for A + B, A‐A + B, and A‐A + B‐B (A‐urethane and B‐hydroxyl) ‐type condensation reactions, and also monomers bearing primary and secondary urethane or hydroxyl functionalities. The transurethane process was confirmed by ¹H and ¹³C NMR, and molecular weight of the polymers were obtained as M_n = 10–15 × 10³ and M_w = 15–45 × 10³ g/mol. The mechanistic aspects of the melt transurethane process and role of the catalyst were investigated using model reactions, ¹H NMR, and MALDI‐TOF‐MS. The model reactions indicated the occurrence of 97% reaction in the presence of catalyst, whereas its absence gave only less than 2% of the product. The polymer samples were subjected for end‐group analysis using MALDI‐TOF‐MS, which confirms the Ti‐catalyst mediated nonisocyanate pathway in the melt transurethane process. Almost all the polyurethanes were stable up to 280 °C, and the T_g of the polyurethanes can be easily fine‐tuned from ?30 to 120 °C by using appropriate diols in the melt transurethane process. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2445–2458, 2008     

Synthesis and characterization of novel aliphatic polycarbonates

A new six‐membered cyclic carbonate monomer, 5‐benzyloxy‐trimethylene carbonate, was synthesized from 2‐benzyloxy‐1,3‐propanediol, and the corresponding polycarbonate, poly(5‐benzyloxy‐trimethylene carbonate) (PBTMC), was further synthesized by ring‐opening polymerization in bulk at 150 °C using aluminum isobutoxide [Al(OⁱBu)₃], aluminum isopropoxide, or stannous octanoate as an initiator. The results showed that a higher molecular weight polycarbonate could be obtained in the case of Al(OⁱBu)_3. The protecting benzyl group was removed subsequently by catalytic hydrogenation to give a polycarbonate containing a pendant hydroxyl group (PHTMC). The polycarbonates obtained were characterized by Fourier transform infrared spectroscopy, ¹H NMR,¹³C NMR, gel permeation chromatography, and DSC. NMR results of PBTMC offered no evidence for decarboxylation occurring during the propagation. The pendant hydroxyl group in PHTMC resulted in an enhancement of the hydrophilicity of the polycarbonate. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 70–75, 2002     

Synthesis and characterization of aromatic cyclolinear phosphazene polyetherketones containing bis‐Spiro‐substituted cyclotriphosphazene unit

A novel monomer, 2,2‐bis‐(4′‐fluorobenzoylphenoxy)‐4,4,6,6‐bis[spiro‐(2′,2″‐dioxy‐1′, 1′‐biphenylyl)] cyclotriphosphazene, was synthesized and polymerized with 4,4′‐difluorobenzophenone as a comonomer and 4,4′‐isopropylidenediphenol or 4,4′‐(hexafluoroisopropylidene) diphenol in N,N‐dimethylacetamide at 162 °C for 4 h to give two series of aromatic cyclolinear phosphazene polyetherketones containing bis‐spiro‐substituted cyclotriphosphazene groups. The structure of the monomer was confirmed by ¹H, ¹³C, and ³¹P NMR. The effect of the incorporation of the bis‐spiro‐substituted cyclotriphosphazene group on the thermal properties of these polymers was investigated by DSC and thermogravimetric analysis. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2993–2997, 2001     

Synthesis and polymerization of styrene monomer carrying isothiocyanate moiety and its copolymerization with HEMA based on chemo‐selectivity to nucleophiles

Isothiocyanate is a very useful functional group for post‐polymerization modification by the reaction with amine or alcohol. An isothiocyanate monomer, 4‐vinylbenzyl isothiocyanate, was synthesized from 4‐vinylbenzyl chloride without using any harmful reagents such as thiophosgene and CS₂. The obtained monomer was successively polymerized by the conventional radical polymerization (AIBN, 1,4‐dioxane, 60 °C) to afford the corresponding polymer. The obtained polymer was characterized by ¹H NMR, FTIR, thermogravimetric analysis (TGA), and differential scanning calorimetry. In contrast to the isocyanate group, the isothiocyanate group was relatively tolerant to alcohols, and this character enabled us to synthesize a copolymer of 4‐vinyl benzylisothiocyanate and (2‐hydroxyethyl methacrylate). The copolymer is transformed into networked polymer by 1,8‐diazabicyclo[5.4.0]undec‐7‐ene as a promoter of the reaction between isothiocyanate and alcohol to afford thiocarbamate. The formation of networked polymer was characterized by FTIR and TGA. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 5215–5220     

Transesterification kinetics of poly(ethylene terephthalate) and poly(ethylene 2,6‐naphthalate) blends with the addition of 2,2′‐bis(1,3‐oxazoline)

The kinetics of the transesterification reaction between poly(ethylene terephthalate) (PET) and poly(ethylene 2,6‐naphthalate) (PEN) with and without the addition of a chain extender were studied with ¹H NMR. Different kinetic approaches were considered, and a second‐order, reversible reaction was accepted for the PET/PEN reactive blend system. The addition of 2,2′‐bis(1,3‐oxazoline) (BOZ) promoted the transesterification reaction between PET and PEN in the molten state. The activation energy of the transesterification reaction for the PET/PEN reactive blend with BOZ (94.0 kJ/mol) was lower than that without BOZ (168.9KJ/mol). The rate constant k took an almost constant value for blend samples with different compositions mixed at 275 °C. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2607–2614, 2001     

Photoswitchable architectural polymer: Toward azo‐based polyamidoamine side‐chain dendritic polyester

A versatile approach to the synthesis of novel polyamidoamine (PAMAM) side‐chain dendritic polyester (SCDPE) possessing azobenzene motifs in the polymeric core is described and displayed reversible cis–trans (E/Z) isomerization upon exposure to UV light. A polymerization reaction was conducted in solution using ester‐terminated PAMAM dendritic diol ( 1a , G 3.5) and azobenzene dicarboxylic acid chloride in the presence of triethylamine. PAMAM dendritic diol 1a as well as SCDPE ( 1 ) were thoroughly characterized by means of IR and NMR (¹H and ¹³C) spectroscopies. The intrinsic viscosity of 1 at 36 °C in CHCl₃ was found to be 0.38 dl/g. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4182–4188, 2001     

New developments in the synthesis and characterization of phosphate esters of linear (per)fluoropolyether monofunctional and difunctional macromonomers

The synthesis of (per)fluoropolyether phosphate esters prepared by the reaction of phosphorus pentoxide and fluorinated alcohols has been investigated. The reactivity strongly depends on the structure of the fluorinated alcohol, generally decreasing with increasing acidity. Moreover, the addition of a modulated amount of water to the starting fluorinated alcohol allows the fine‐tuning of the monoalkylester and dialkylester contents in the final products. Therefore, when difunctional perfluoropolyether macromonomers are considered, the polymerization degree can be varied, and phosphate oligoesters of different molecular weights can be obtained in high yields, even if, as in this study, the synthesis is focused on low‐molecular‐weight oligomers. This easy control of the oligoester composition in the final product makes it possible to address the synthesis of phosphate oligoesters having a well‐defined equivalent weight, which also depends on the average molecular weight of the starting alcohol. The full characterization of the products is made possible by the combination of different NMR techniques (¹H, ¹⁹F, ³¹P, ¹³C, and two‐dimensional NMR: ³¹P–¹H and ³¹P–¹³C). This synthetic route shows great potential and opens the way to a new family of interesting candidates for the treatment of different organic or inorganic substrates to impart phobic properties against both polar and apolar substances. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4790–4804, 2005     

Chemoselective polyesterification by direct polycondensation

A convenient method for the synthesis of polyester‐containing amino substitutes on the aromatic rings of the backbone has been developed. This polyester was prepared by chemoselective polyesterification of isophthalic acid with bisphenol having an amino group in the presence of the condensing agent diphenyl(2,3‐dihydro‐2‐thioxo‐3‐benzoxazolyl)phosphonate ( 1 ) and 1,5‐diazabicyclo[4,3,0]‐5‐nonene as a base. The model reactions were carried out in detail to elucidate appropriate conditions of chemoselective polyesterification. Direct polycondensation of isopthalic acid with 4,4′‐[1‐(4‐aminophenyl)ethylidene]bisphenol proceeded smoothly under mild conditions and produced the desired polyester with a number average molecular weight of 11,000 and M_w/M_n of 2.22. The polymer obtained was characterized by IR, ¹H, and ¹³C NMR spectroscopies. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 78–85, 2001     

Rare‐earth‐catalyzed alternating copolymerization of carbon monoxide with styrene

Rare‐earth acetates were used to catalyze the copolymerization reaction of carbon monoxide and styrene. Cupric acetate, 1,10‐phenanthroline, p‐toluenesulfonic acid, and 1,4‐benzoquinone were also added to the catalyst system. The structures of the copolymers obtained were characterized with IR, ¹H NMR, ¹³C NMR, wide‐angle X‐ray diffraction, and elemental analysis methods. The relationship between the catalytic activity and the catalyst composition was studied in detail. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 642–649, 2002; DOI 10.1002/pola.10147