Polyurethane anionomers. I. Structure properties of polyurethane anionomers

The influence of mono and divalent nontransition and transition metals on the glass transition and mechanical properties of polyurethane anionomers have been investigated. NCO-terminated prepolymer prepared from 4,4′-methylene-bis(phenyl isocyanate) (MDI) and poly(caprolactone) glycol (PCL) was chain extended with dimethylolpropionic acid (DMPA), and the anionomers obtained by neutralization of the prepolymer. The glass transition temperatures of polyurethane anionomers have been studied as a function of the counterion. From simple electrostatic considerations, it is shown that a linear relationship exists between the glass transition temperature and ionic potential (?) for these particular materials. The relation is; T_g = A? + B. The mechanical properties are greatly affected by the type of the counterion, and in some cases, such as monovalent and nontransition metals, the mechanical properties of the anionomers improved by increasing the ionic potential. On the other hand, transition metals containing anionomers exhibited good mechanical properties but no relationship was observed between the mechanical properties and the ionic potential. The extent of water absorption of PU anionomers follows the same relative trends as the tensile strengths of the transition metals with filled and partially filled d-orbitals.     

Polyurethane anionomers synthesised with aromatic, aliphatic or cycloaliphatic diisocyanates, polyoxyethylene glycol and 2,2-bis-(hydroxymethyl)propionic acid. Part 3. Electrical properties of polyurethane coatings

The following electrical properties were found for polymer coatings obtained from polyurethane anionomers synthesised with the use of various diisocyanates: volume resistivity, permittivity and dielectric dissipation factor. The effects were discussed from the molecular structures and phase structures of those anionomers on the value of their ionic conductivity and polarizability. The anionomer prepared from the aliphatic diisocyanate was found to offer ionic conductivity; hence, that material can be considered to be a solid electrolyte, which exhibits a considerable susceptibility to structural modifications in the alternating electric field.     

Synthesis and optical properties of new polyurethane cationomers with anchored stilbene chromophores

An ionic diol bearing a one‐sided urethane‐stilbene group located on the ammonium quaternary structure was prepared and proposed as an intermediate for polyurethane ionomer synthesis. Polyurethane cationomers with stilbene ionic groups based on poly(tetramethylene oxide) diols, 4,4′‐diphenylmethane diisocyanate and the aforementioned ionic diol, were synthesized and characterized. Some aspects of the trans–cis photoisomerism and fluorescent emission of the stilbene chromophore in polyurethane cationomers were studied comparatively with the urethane‐stilbene diol. The stilbene polycations absorbed at λ_A = 316 nm and emitted violet‐blue light with an emission maxima at λ_F = 444 nm (dimethylformamide solution) and λ_F = 465 nm (film). These polymers are known for their elastomeric properties and are assumed to be of great interest for some future applications. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1918–1928, 2002     

磺酸型阴离子聚氨酯离聚物的研究(Ⅰ)——不同离子化程度对性能的影响

合成了不同离子化程度的磺酸型阴离子聚氨酯离聚物,并通过红外光谱、示差扫描量热、动态力学、应力-应变等方法研究了它们的性能,结果表明:离子化程度不同对聚氨酯离聚物的软硬段相容性有较大的影响,引入少量离子,使软硬段相容性提高,引入大量离子时,则又使软硬段相分离程度提高,随着离子化程度的提高,材料的抗张强度、水溶性逐步提高,为控制聚氨酯材料的亲水性及制备水溶性聚氨酯提供了一种新途径。     

Polyurethane anionomers synthesised with aromatic, aliphatic or cycloaliphatic diisocyanates, polyoxyethylene glycol and 2,2-bis-(hydroxymethyl)propionic acid. Part II. Supermolecular structure. Thermal properties

Small angle X-ray scattering and differential scanning calorimetry methods were employed to characterise the internal order of structural phases present in polyurethane coatings obtained as a result of water evaporation from anionomer dispersions. Those anionomers were produced in the reaction of aromatic, cycloaliphatic and aliphatic diisocyanates with polyoxyethylene glycol, 2,2-bis-(hydroxymethyl)propionic acid and 1,6-hexamethylenediamine. The decisive effects were found from ionic and polar structures within the rigid urethane and urea segments on the ordered arrangement degree of the supermolecular structures in the obtained anionomers. That becomes apparent in differential scanning calorimetry thermograms and contributes to improved thermal stability of the produced polyurethane coatings.     

On the study of structure property of polypropylene-glycol based polyurethane ionomer

Water-based polyurethane ionemers which have been successfully synthesized at our lab are demonstrated to be polypropylene glycol-based polyurethane ionomers by FT-IR spectra. For polyurethane ionomers prepared at a fixed ratio of NCO to OH as a function of ionic content, their viscosities are seen to be higher for polypropylene glycol with molecular weight of 1500 (triols) than for polypropylene glycol with molecular weight of 1000 (diols) or 2000 diols based polyurethane ionomers, as a result of strong intra ionic chain interaction. On the other hand, the viscosities due to strong inter chain interaction appear to be higher for polypropylene glycol with molecular weight of 1000 than for polypropylene glycol with molecular weight of 1500 or 2000-based polyurethane ionomers made at a fixed ionic content and under the variation of the ratio of NCO/OH. Like surfactant, poly-propylene glycolbased polyurethane ionomers present in water can substantially reduce the surface tension-of water. Thus, it may be considered as an ionomer-like surfactant.     

Synthesis of N-(arylmethyl)diethanolamines and of other pyrenediols: Addition polymerizations of pyrenyl monomers

N-(Arylmethyl)diethanolamines and other spaced dihydroxy compounds bearing pyrenyl groups were prepared using benzotriazole as a synthetic auxiliary. The potential of these diols as precursors for the preparation of condensation polymers containing pendant polycyclic aryl groups was illustrated by reaction of the pyrenyl derivatives with diisocyanates which afforded the corresponding polyurethane polymers.     

Segmented polyurethane elastomers derived from aliphatic polycarbonate and poly(ester‐carbonate) soft segments for biomedical applications

A series of biomedical polyurethane elastomers (PURs) based on poly(ester‐carbonate)s (PECs) and polycarbonates (PCs) were synthesized and spectrally characterized fully. PEC or PC diols were synthesized by the ring‐opening polymerization of ε‐caprolactone, trimethylene carbonate, and neopentyl carbonate catalyzed by lipase from Candida antarctica. PURs were prepared by free‐metal method from PEC or PC diols and 4,4′‐methylenebis(phenyl isocyanate), with 1,4‐butanediol as a chain extender. The physical and mechanical properties as well as hydrolytic stability of the obtained PURs were determined. The toxicity of the received polymers was evaluated using bacterial luminescence test and two protozoans assays. The presented preliminary studies suggest that PEC or PC diols prepared in this way might be applied for the synthesis of biomedical PURs with improved hydrolytic stability. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Hydroxy-terminated poly(ε-caprolactone-co-δ-valerolactone) oligomers: Synthesis,characterization, and polyurethane network formation

Difunctional hydroxy-terminated poly(ε-caprolactone-co-ε-valerolactone) (PCV) oligomers were synthesized by the diol-initiated bulk copolymerization of ε-caprolactone (C) and δ-valerolactone (V). The two homopolymers were semicrystalline, with almost identical melting temperatures; copolymerization significantly lowered the melting point (T_m) compared to either homopolymer. Copolymer melting points were found to decrease with decreasing molecular weight and to be dependent on composition, i.e., the incorporation of a comonomer into either homopolymer resulted in a decrease in T_m, with the maximum decrease occurring at a copolymer composition of about 60 mol % ε-caprolactone. The molar compositions of the copolyesters were determined from ¹³C-NMR spectra. The reactivity ratios of the two monomers (M₁ = C, M₂ = V) were determined to the r₁ = 0.25 and r₂ = 0.49. Number average molecular weight (M?_n) of the PCV diols was inversely proportional to the initial diol concentration within the studied molecular weight range of 900 to 11,100 g/mol. Crosslinked polyurethane networks were prepared by reacting PCV diols with triphenylmethane triisocyanate. Network characterization included determination of sol content by solvent extraction, glass transition (T_g) and T_m by DSC, and tensile properties by stress-strain measurements. Completely amorphous networks resulted from PCV diols of M?_n ≤ 2,400; semicrystalline networks resulted from PCV diols of M?_n ≥ 3,600.     

Synthesis and characterization of polyurethane anionomers with bisazoaromatic chromophores and carboxylate groups

A new diol with a bisazoaromatic pendant was prepared to obtain photosensible polymers suitable for dyed aqueous systems. A polyurethane bearing bisazoaromatic chromophores, based on a poly(tetramethylene oxide) diol (average molecular weight = 2000), 2,4‐tolylene diisocyanate, and the aforementioned azo diol, was synthesized and characterized. Bichromophoric polyurethane anionomers, prepared by a two‐step substitution of urethane hydrogen atoms with sodium carboxylate groups, were studied. The influence of the concentration of carboxylate groups (30–158 mequiv of ionic groups/100 g of polymer) on some polymer properties and photoisomerism in polymer solutions and thin films was examined. In particular, the polymer structure and its morphology dictated the proximity of anchored bisazo chromophores and the capability of intermolecular forces between dyes producing hydrogen aggregates in solutions and thin films. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5463–5470, 2004     

Ultraviolet-curable epoxy acrylate dispersions: effect of urethane acrylate anionomers on stabilizing and film properties

 Epoxy acrylate dispersions stabilized using urethane acrylate anionomers were prepared for an application of ultraviolet (UV) curing. By observing the optical microscopy and colloidal stability for the epoxy acrylate dispersions, it was confirmed that the urethane acrylate anionomers incorporated have an interfacial activity in the interface between the epoxy acrylate oil and the water/ ethanol mixture (80/20, w/w). This was possible by the structurally designed urethane acrylate anionomers, containing a hydrophobic soft segment and two hydrophilic ionic sites in their molecules. In addition, when ultraviolet (UV)-cured, the urethane acrylate anionomers agglomerated to form the rubber domains in the epoxy acrylate film, which were induced by the ionic interaction. Consequently, this agglomerated rubber domains improved the final film properties. Received: 4 April 1998 Accepted: 1 July 1998     

Polyurethane anionomers synthesised with aromatic, aliphatic or cycloaliphatic diisocyanates, polyoxyethylene glycol and 2,2-bis(hydroxymethyl)propionic acid

Taking advantage of the step-growth polyaddition method, which has been developed earlier, and applying it in the reaction of aromatic, cycloaliphatic and aliphatic diisocyanates with polyoxyethylene glycol, 2,2-bis(hydroxymethyl)propionic acid and 1,6-hexamethylene-diamine, a few polyurethane anionomers were synthesised, which were recovered from aqueous dispersions in the form of thin polymeric films. Analytical chemistry methods, like gel permeation chromatography with N,N-dimethylacetamide as the polar eluent and high-resolution nuclear magnetic resonance and IR spectroscopy, were employed to confirm their chemical structures, to find molecular weights and their distribution and to characterise the polarity of the chemical structure of the polyurethane chain formed.     

A study of starch addition on burst effect and diameter of polyurethane microspheres containing theophylline

Theophylline was encapsulated in polyurethane prepared with hexamethylene diisocyanate (HMDI), polycaprolactone (PCL) (M_W = 530 and 2000 g/mol) diols, and starch as polyols and butanediol as chain extender. Polyurethane microspheres were prepared in two reactors; after polyurethane preparation by mixing PCL/starch, HMDI and theophylline in the first reactor, microspheres formation was achieved by transferring the reaction mixture to an aqueous medium (moving at 5000 rpm) of the second reactor. Fourier transform infrared (FTIR) was employed to confirm polyurethane formation during the course of reactions. FTIR spectrum revealed bands at 1729–1733 cm^?1 and 3340–3347 cm^?1 which indicates carbonyl and NH of amine groups, respectively. Scanning electron microscopy (SEM) was used to study the morphology of the samples. SEM confirmed the formation of microspheres with spherical morphology. Particle size investigation with optical microscopy revealed a size distribution of 8–70 µm. Controlled release of theophylline from the microspheres was performed in phosphate buffered saline (PBS) at pH = 7.4 and monitored with a ultraviolet (UV) spectrometer at 274 nm. Drug release profiles showed that starch addition reduced the release rate around 24% for microspheres prepared from PCL with a molecular weight of 2000 g/mol and it had negligible effect on a molecular weight of 530 g/mol. Copyright © 2007 John Wiley & Sons, Ltd.     

Dicarboxylic acid promoted immortal copolymerization for controllable synthesis of low‐molecular weight oligo(carbonate‐ether) diols with tunable carbonate unit content

Low‐molecular weight oligo(carbonate‐ether) diols are important raw materials for polyurethane formation, which with tunable carbonate unit content (CU) may endow new thermal and mechanical performances to polyurethane. Herein, facile synthesis of oligo(carbonate‐ether) diols with number average molecular weight (M_n) below 2000 g mol^?1 and CU tunable between 40% and 75% are realized in high activity by immortal copolymerization of CO₂/propylene oxide (PO) using zinc‐cobalt double metal cyanide complex (Zn‐Co‐DMCC) in the presence of sebacic acid (SA). M_n of the oligomer is in good linear relationship to the mole ratio of PO and SA (PO/SA) and hence can be precisely controlled by adjusting PO/SA. Besides, the molecular weight distribution is quite narrow due to the rapid reversible chain transfer in the immortal copolymerization. High pressure and low temperature are favorable for raising CU. In all the reactions, the weight fraction of propylene carbonate (W_PC) can even be controlled as low as 2.0 wt %, and the catalytic activity of Zn‐Co‐DMCC is above 1.0 kgg^?1 cat. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Segmented polyethylene oxides: A new class of polyethers prepared via melt transetherification

Several segmented polyethylene oxides (SPEOs) were prepared by a melt-transetherification process using 1,4-bis(methoxymethyl)-2,3,5,6-tetramethylbenzene and polyethylene glycols (PEGs) of different molecular weights (di-, tri-, and tetraethylene glycols and PEGs of molecular weights 300, 600, 1000, 1500, and 3400) as the monomers. The effect of polymerization temperature (185 and 150 °C) on the molecular weight of SPEOs was studied, and it was shown that the molecular weight is larger at a higher polymerization temperature. The reversal of the polycondensation (transetherification) equilibrium by treatment of the polyethers with excess methanol transformed them completely into the starting monomers. The analysis of the degraded products by mass and NMR spectroscopies revealed that side reactions, such as the self-condensation of diols, are insignificant. The polymers containing shorter PEG spacers are amorphous, whereas the ones with longer PEG spacers are semicrystalline. The glass-transition temperature (T_g) of the SPEOs decreased with increases in the spacer length and attained the value of PEO at PEG-600, whereas the melting transition (T_m), crystallization temperature (T_c), and their enthalpies of transition, (ΔH_m) and (ΔH_c), increased with increases in the spacer length. The introduction of “molecular kinks” into SPEOs by the use of another monomer, 1,3-bis(methoxymethyl)-2,4,5,6-tetramethylbenzene, surprisingly, showed little effect on their thermal properties. A “branched-PEO” analogue, containing pendant oligoethyleneoxy units, was also prepared, and its thermal properties were compared with its linear analogue. Preliminary ionic conductance measurements showed that some of these SPEOs could serve as potential candidates for solid polymer–electrolyte applications. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1615–1628, 2001     

Preparation of Chiral Hydroxy Carbonyl Compounds and Diols by Ozonolysis of Olefinic Isoborneol and Fenchol Derivatives: Characterization of Stable Ozonides by 1H-, 13C-, and 17O-NMR and Electrospray Ionization Mass Spectrometry

The allylic and homoallylic alcohols 1 – 8 , prepared from (+)-camphor and (−)-fenchone, were ozonized in Et₂O at −78° and treated with Et₃N or LiAlH₄ to give the chiral hydroxy carbonyl compounds 9 – 16 and the diols 17 – 24 , respectively (Scheme 1). In the case of the diols 19 and 24 , the formation of new chiral centers proceeded with high diastereoselectivity. These diols were prepared highly diastereoselectively also by LiAlH₄ reduction of the hydroxy carbonyl compounds 11 and 16a , respectively (Scheme 2). The absolute configuration of the new chiral centers in 19 and 24 was determined by X-ray and NMR methods. The ozonization of compounds 2 , 3 , 7 , and 8 provided the relatively stable hydroxy-substituted 1,2,4-trioxolane derivatives (ozonides) 37 – 40 (Scheme 5) which were characterized by ¹H- and ¹³C-NMR spectra, ESI-MS, and natural-abundance ¹⁷O-NMR spectra.     

Ionic conductivity probed in main chain liquid crystalline azobenzene polyesters

Three main chain thermotropic liquid crystalline (LC) azobenzene polymers were synthesized using the azobenzene twin molecule (P4P) having the structure Phenylazobenzene‐tetraethyleneglycol‐Phenylazobenzene as the AA monomer and diols like diethylene glycol, tetraethylene glycol (TEG), and hexaethylene glycol as the BB comonomer. Terminal ? C(O)OMe units on P4P facilitated transesterification with diols to form polyesters. All polymers exhibited stable smectic mesophases. One of the polymers, Poly(P4PTEG) was chosen to prepare composite polymer electrolytes with LiCF₃SO₃ and ionic conductivity was measured by ac impedance spectroscopy. The polymer/0.3 Li salt complex exhibited a maximum ionic conductivity in the range of 10^?5 S cm^?1 at room temperature (25 °C), which increased to 10^?4 S cm^?1 above 65 °C. The temperature dependence of ionic conductivity was compared with the phase transitions occurring in the sample and it was observed that the glass transition had a higher influence on the ionic conductivity compared to the ordered LC phase. Reversible ionic conductivity switching was observed upon irradiation of the polymer/0.3 Li salt complex with alternate UV and visible irradiation. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 629–641     

Polyurethane-polymethacrylic acid multiblock copolymer dispersions through polyurethane macroiniferters

Polyurethane-polymethacrylic acid multiblock copolymers have been prepared from tetraphenylethane-based polyurethane macroiniferters. Aqueous dispersions of these block copolymers and their anionomers have been prepared. Anionomeric dispersions have smaller particle size and higher viscosity when compared to their corresponding block copolymeric dispersions. Particle size decreases whereas viscosity increases when the degree of neutralization is increased. Tensile strength and initial modulus are higher for films derived from anionomeric dispersions than for the corresponding block copolymeric films. Received: 13 March 1998 Accepted in revised form: 13 November 1998     

New polymer syntheses. LXXXII. Syntheses of poly(ether-sulfone)s from silylated aliphatic diols including chiral monomers

Attempts were made to synthesize poly(ether-sulfone)s from aliphatic diols or bissilylated diols on the one hand, and 4,4′-dichlorodiphenylsulfone or 4,4′-difluorodiphenylsulfone on the other hand. The reaction conditions and the catalyst were varied. Polycondensations of silylated diols with 4,4′-difluorodiphenylsulfone and powdered K₂ CO₃ in N-methylpyr-rolidone proved to give the best results. Using silylated isosorbide and isomannide as mono-mers chiral poly(ether-sulfone)s were prepared. GPC measurements indicate weight-average molecular weights in the range of 27×10³–200×10³. © 1995 John Wiley & Sons, Inc.     

Synthesis and Thermal Properties of Biodegradable Poly(ester‐urethane)s Based on Chemo‐Synthetic Poly[(R,S)‐3‐hydroxybutyrate]

A series of telechelic oligo[(R,S)‐3‐hydroxybutyrate]‐diols (PHB‐diols) was synthesized from ethyl (R,S)‐3‐hydroxybutyrate (ethyl (HB)) and four different aliphatic diols, namely, 1,4‐butanediol, 1,6‐hexanediol, 1,8‐octanediol and 1,10‐decanediol by transesterification and condensation in bulk. The structures of the synthesized oligomers were confirmed by ¹H NMR spectroscopy and MALDI‐TOF mass spectroscopy. The use of 1,4‐butanediol results in an oligoester with hydroxyl functionality of approximately 2. In the case of the higher aliphatic diols, the number average functionalities were found to be lower than 2. These differences were ascribed to side reactions which occur during polymerization, yielding unreactive end groups. Other novel families of biodegradable poly(ester‐urethane)s were synthesized either from PHB‐diol alone, or PHB‐diol mixed with poly(ε‐caprolactone)‐diol (PCL‐diol), poly(butylene adipate)‐diol (PBA‐diol) or poly(diethylene glycol adipate)‐diol (PDEGA‐diol). In each case, 1,6‐hexamethylene diisocyanate was used as a nontoxic connecting agent. The homopolymers prepared from PCL‐diol, PBA‐diol and PDEGA‐diol were also synthesized for the sake of comparison. All the prepared copolymers possess high molecular weight with glass transition temperature (T_g) values varying from –54 to –23°C. Some of the prepared copoly(ester‐urethane)s are partially crystalline with melting temperatures (T_m's) varying from 37 to 56°C.