Boric acid binding studies with diol containing polyethylenimines as determined by 11B NMR spectroscopy

Three water‐soluble polymers incorporating increasing levels of 2,3‐dihydroxy propyl attached to polyethylenimine (PEI) backbone were synthesized, characterized by NMR, and investigated for their ability to bind boric acid (BA). ¹¹B NMR spectroscopy showed that BA interacted with the polymeric 2,3‐dihydroxy propyls by forming borate monoester and borate diesters in the boron concentration range of 100–1000 ppm and at 0.0775M polymer. Borate monoester species predominated for low functionalization levels (33% of the PEI amines functionalized), whereas borate diester species dominated for the higher functionalized polymers (66–100% of the PEI amines functionalized). All three polymers showed that 100% of the BA was bound as a mixture of borate mono‐ and diesters at 100‐ppm boron. The overall best performer based on total borate ester formation was the 2/3‐PEI, with a binding K_d of 631 at 200 ppm boron. Borate ion concentration was measured from the ¹¹B NMR chemical shift of the BA/borate peak and it decreased as 1/3‐PEI > 2/3‐PEI > 3/3‐PEI. Variable temperature ¹¹B NMR showed drastic reduction of borate ester species at 65°C. Thus, PEI polymers, as the ones investigated in this work, are reasonable candidates for the selective recovery and recycle of BA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4411–4418, 2006     

Synthesis of formaldehyde polymers from benzene‐1,2‐diol,phenolic alkane‐1,2‐diol,and phenolic alkane‐1,3‐diol as immobilized chelatants for borate anion

A variety of phenolic aryl‐1,2‐ and 1,3‐diols have been condensed with formaldehyde to form polymers serving as immobilized chelatants for borate anions. In this way, polymers from 1,2‐dihydroxybenzene, 2‐hydroxymethylphenol, and a 3‐methyl derivative (saligenins) and 2‐(4‐hydroxyphenyl)‐propane‐1,3‐diol have been converted into formaldehyde polymers with an increasing level of conformational mobility in the diol moiety of the polymer. The extraction of borate from alkaline solutions with three types of polymers has been examined, and the polymer containing planar 1,2‐dihydroxybenzene has been found to be superior to a saligenin‐ and 2‐(4‐hydroxyphenyl)‐ propane‐1,3‐diol‐derived polymer. This suggests that conformational mobility is not an important structural feature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Boron Removal by Polymer-Assisted Ultrafiltration

Abstract

Boron contamination of natural waters is a widespread environmental problem which lacks a cost-effective solution. Polymer-assisted ultrafiltration is a method of boron removal that is compatible with other water-treatment processes. This boron removal technique exploits the pH-dependent complexation between boric acid and a macromolecule containing vicinal diol groups to prevent boric acid from passing through an ultrafiltration membrane. The concentration of boron in treated water was reduced from 10.5 ppm to less than 2 ppm through ultrafiltration of an aqueous solution containing boric acid and a polymer synthesized by grafting N-methyl-D-glucamine (NMG) onto poly(epichlorohydrin). The NMG groups, when tethered to the polymer, exhibited stronger affinity for boron than expected from equilibria between NMG and boric acid.     

Characterization of 2‐(2‐methoxyethoxy)ethanol‐substituted phosphazene polymers using pervaporation,solubility parameters,and sorption studies

Two linear phosphazene polymers were synthesized with differing amounts of hydrophilic 2‐(2‐methoxyethoxy)ethanol (MEE) and hydrophobic 4‐methoxyphenol (MEOP) substituted on the backbone. These high polymers were cast into membranes and their permeability to water, methanol, ethanol, and 2‐propanol was evaluated as a function of temperature. An additional polymer with a low content of MEE was studied for water permeation and was characterized by trace flux. At higher levels of MEE on the backbone, fluxes of all solvents increased. Solubility also was found to increase with increasing MEE content for all solvents except water. Unexpectedly, water was found to be less soluble in the higher MEE polymer, although higher membrane fluxes were observed. Diffusion coefficients showed the following trend: methanol ? 2‐propanol > ethanol ? water. Finally, the affinity of solvents and polymers was discussed in terms of Hansen solubility parameters. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 939–945, 2005     

Polymeric drug carriers functionalized with pairwise arranged hydroxyl and/or carboxyl groups for platinum chelation

Cancer chemotherapy, alone or in combination with other treatment modalities, has come to play an important part in the fight against malignancies. However, the anticancer drugs in current clinical administration, while efficacious and oftentimes curative against a select number of neoplasias, suffer from a variety of deficiencies, notably severe systemic toxicity and a tendency to elicit drug resistance. These pharmacological shortcomings are eminently in evidence with the outstanding class of platinum drugs as represented by cis‐diaminedichloroplatinum(II) (cisplatin). The bioreversible binding (conjugating) of a medicinal agent to a water‐soluble macromolecular carrier has been recognized as an effective expediency to curtail these deficiencies. In the present communication we describe the synthesis of a special class of polymers featuring hydroxyl and/or carboxyl functionalities designed for use in the construction of square‐planar platinum complexes polymer‐bound through dihydroxylato, hydroxylatocarboxylato, or dicarboxylato chelation. Accordingly, the polymer structures of this project contain pairs of hydroxyl, hydroxylcarboxyl, or carboxyl groups main chain‐ or side chain‐attached in 1,2‐geometry. The target polymers are obtained by a Michael addition type polymerization of bisacrylamide monomers with mono‐ or diamine comonomers in aqueous medium. Whereas in the first three polymers the hydroxyl and/or carboxyl functionalities are attached directly (1) or close (2, 3) to the backbone, the remaining polymers contain these functionalities as terminals on extended spacer segments. The water‐soluble polymeric products, purified and fractionated by dialysis and isolated by freeze‐drying, will be used as substrates for platinum conjugation in future work. However, their functional proneness to platinum binding is demonstrated in the present project through platination of an exemplifying carrier, providing a water‐soluble conjugate with a Pt content of 13.5%. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 10–19, 2005     

Poly(1,2‐diaminobenzene) and poly(1,3‐diaminobenzene): Synthesis,characterization, and properties

Poly(1,2‐diaminobenzene) (1,2‐DAB) and poly(1,3‐diaminobenzene) (1,3‐DAB) have been synthesized by using ammonium persulfate as oxidizing agent in the presence and in the absence of the following metal ion salts: CuCl₂, NiCl₂, and CoCl₂ with different HCl concentrations. The products showed a different content of the metal ion depending on the HCl concentration. The polymers were characterized by Fourier transform infrared (FTIR), ultraviolet‐visible (UV‐Vis) spectroscopy, thermal analysis, and electrical conductivity. The polymerization yield depended on the presence of metal ions that can react as oxidizing reagents and/or catalysts. The polymerization mechanism depended on the position of the substituent. For poly(1,2‐DAB) a ladder‐type structure was obtained, and for poly(1,3‐DAB) one similar to that of polyaniline. The thermal stability increased as the metal ion content in the polymer matrix increased. The electrical conductivity of the polymer did not depend on the metal ion content in the polymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2564–2572, 2002     

Synthesis and Reactions of Enantiopure Substituted Benzene cis‐Hexahydro‐1,2‐diols

Enantiopure cis‐dihydro‐1,2‐diol metabolites, obtained from toluene dioxygenase‐catalysed cis‐dihydroxylation of six monosubstituted benzene substrates, have been converted to their corresponding cis‐hexahydro‐1,2‐diol derivatives by catalytic hydrogenation via their cis‐tetrahydro‐1,2‐diol intermediates. Optimal reaction conditions for total catalytic hydrogenation of the cis‐dihydro‐1,2‐diols have been established using six heterogeneous catalysts. The relative and absolute configurations of the resulting benzene cis‐hexahydro‐1,2‐diol products have been unequivocally established by X‐ray crystallography and NMR spectroscopy. Methods have been developed to obtain enantiopure cis‐hexahydro‐1,2‐diol diastereoisomers, to desymmetrise a meso‐cis‐hexahydro‐1,2‐diol and to synthesise 2‐substituted cyclohexanols. The potential of these enantiopure cyclohexanols as chiral reagents was briefly evaluated through their application in the synthesis of two enantiomerically enriched phosphine oxides from the corresponding racemic phosphine precursors.     

Thermo‐responsive polyurethane hydrogels based on poly(ethylene glycol) and poly(caprolactone): Physico‐chemical and mechanical properties

In this work, we present the synthesis and characterization of chemically crosslinked polyurethanes (PU) composed of poly(ethylene glycol) (PEG) and poly(caprolactone) diol (PCL‐diol), as hydrophilic and hydrophobic segments respectively, poly(caprolactone) triol (PCL‐triol), to induce hydrolysable crosslinks, and hexamethylene diisocyanate (HDI). The syntheses were performed at 45 °C, resulting in polyurethanes with different PEG/PCL‐diol/PCL‐triol mass fractions. All the PUs are able to crystallize and their thermal properties depend on the global composition. The water uptake capacities of the PU increase as the PEG amount increases. The water into hydrogels is present in different environments, as bounded, bulk and free water. The PU hydrogels are thermo‐responsive, presenting a negative dependence of the water uptake with the temperature for PEG rich networks, which gradually changes to a positive behavior as the amount of poly(caprolactone) (PCL) segments increases. However, the water uptake capacity changes continuously without an abrupt transition. Scanning electron microscopy (SEM) analyses of the hydrogel morphology after lyophilization revealed a porous structure. Mechanical compression tests revealed that the hydrogels present good resilience and low recovery hysteresis when they are subject to cycles of compression–decompression. In addition, the mechanical properties of the hydrogels varies with the composition and crosslinking density, and therefore with the water uptake capacity. The PU properties can be tuned to fit for different applications, such as biomedical applications. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43573.     

Syntheses and properties of cross‐linked polymers from functionalized triglycerides

A number of functionalized triglycerides were synthesized from glyceryl trioleoate via epoxidation followed by reduction to give glyceryl tris(9‐hydroxy)trioleoate (a triol) or hydrolytic ring opening to obtain glyceryl tris(9,10‐dihydroxy)trioleoate (a hexaol). A selective monoepoxidation reaction of glyceryl trioleoate was also carried out and the resulting monoepoxide was hydrolyzed to give glyceryl 9,10‐dihydroxytrioleoate (a diol). Glyceryl tris(9‐hydroxy)trioleoate was brominated followed by displacement with sodium azide and reduction to give glyceryl tris(9‐amino)trioleoate (a triamine) and glyceryl tris[9‐(N‐isopropylamino)]trioleoate. These functionalized triglycerides were crosslinked with 1,4‐phenylene diisocyanate. The crosslinked polymers exhibit thermoset characteristics. Thermal analysis results suggest that the polymers are in amorphous states, and their thermal stability was significantly affected by crosslink degree. The crosslinked polymer derived from the diol retained 56% of its weight at 408°C, whereas the polymers derived from the aforementioned hexaol with higher crosslink degree retained only 36% of the original weight. Glass transition temperatures of these polymers range from ?1.0°C to 10.2°C. The thermal stable polymer, 12 , derived from the aforementioned diol exhibits a linear viscoelastic character and can be used as thermoplastics. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Fine‐tuning the mechanical properties of hydroxyl‐terminated polybutadiene/ammonium perchlorate‐based composite solid propellants by varying the NCO/OH and triol/diol ratios

Changes in the mechanical properties of hydroxyl‐terminated polybutadiene/ammonium perchlorate‐based composite solid propellants were studied during the curing period with respect to variations in the crosslink density, which was predominantly determined by the equivalent ratio of diisocyanate to total hydroxyl (NCO/OH ratio) and the equivalent ratio of triol to diol (triol/diol ratio). For this purpose, 16 propellants were prepared in different compositions through changes in the NCO/OH ratios (0.81, 0.82, 0.83, and 0.85) for each triol/diol ratio (0.07, 0.09, 0.11, and 0.13) and were tested for their mechanical properties immediately after curing. The propellants with an NCO/OH ratio of 0.82 had minimum stress, modulus, and hardness with maximum strain capability, whereas the propellants with an NCO/OH ratio of 0.85 showed just the opposite behavior. Variations in the isocyanate level seemed to have more effect on the mechanical properties at higher triol/diol ratios. It was also concluded that the propellants with triol/diol–NCO/OH combinations of 0.11–0.83, 0.11–0.85, 0.13–0.81, 0.13–0.83, and 0.13–0.85 were not acceptable for upper stage case‐bonded rocket applications because of either high tensile strength or high modulus. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2072–2079, 2002; DOI 10.1002/app.10605     

Novel redox‐active polycarbazole‐functionalized polycatechol network films produced by controlled electropolymerization

A novel precursor, 1,2‐bis[6‐(9H‐carbazol‐9‐yl)hexyloxy] benzene (BCHB), was successfully synthesized. Its polycarbazole‐functionalized polycatechol network films, poly{1,2‐bis[6‐(9H‐carbazol‐9‐yl)hexyloxy] benzene} (PBCHB), with good redox activity were formed by the direct anodic oxidation of BCHB in CH₂Cl₂ and boron trifluoride diethyl etherate binary solvent solution. Ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, ¹H‐NMR, and matrix‐assisted laser desorption ionization–time of flight mass spectrometry were used to characterize the polymers. The results indicate that the network polymers could be synthesized electrochemically with different polymerized units by controlled electropolymerization. The PBCHB films prepared at low potential were oligomers with short conjugation lengths and were soluble in common organic solvents, whereas the polymers with long conjugation lengths and hyperbranched network structures obtained at high potential were insoluble. The electrosynthesized polymers exhibited blue emission maxima around 450 nm and were much more redshifted than their monomer. The emissions were also brighter; this indicated the polymers are potential good blue‐light emitters. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Aging of HTPB/AP‐based composite solid propellants,depending on the NCO/OH and triol/diol ratios

Aging behavior of hydroxyl‐terminated polybutadiene/ammonium perchlorate (HTPB/AP)‐based composite solid propellants was studied as a function of crosslink density, which is predominantly determined by the molar ratio of diisocyanate to total hydroxyl (NCO/OH ratio) and the molar ratio of triol to diol (triol/diol ratio). For this purpose, 16 propellant samples with different compositions were prepared by changing the NCO/OH ratio as 0.81, 0.82, 0.83, and 0.85 for each triol/diol ratio of 0.07, 0.09, 0.11, and 0.13, and subjected to an accelerated aging at 65°C. The changes in the mechanical properties were monitored throughout the aging period. In the initial part of the aging period, a sharp increase in stress, modulus, and hardness values and a sharp decrease in strain values were observed for all the propellants. At further stages of aging, only slight changes were observed in the mechanical properties. Concerning the aging criterion as reduction in the strain capability more than the half of the initial value, the propellants with respective NCO/OH‐triol/diol ratios of 0.81–0.09, 0.85–0.09, 0.81–0.13, 0.83–0.13, and 0.85–0.13 can be considered to be aged with time. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 959–964, 2001     

Polyester resins with carbazole ring

3‐(9‐Carbazolyl)propane‐1,2‐diol was obtained in the reaction of 9‐(2,3‐epoxypropyl)carbazole with water. The obtained diol was further used for modification of unsaturated polyester resin to produce enhanced thermal and heat resistance in comparison with classic resins. The properties of polyesters and polyester resins modified with 3‐(9‐carbazolyl)propane‐1,2‐diol were studied in detail. When 3‐(9‐carbazolyl)propane‐1,2‐diol is used instead of propylene glycol the unsaturated polyester resins possess enhanced thermal stability.© 2013 Society of Chemical Industry     

N,N‐diethyl dithiocarbamato group induced photografting of methyl methacrylate onto polyurethane

The N,N‐diethyl dithiocarbamato group present in a variety of compounds acts as an initiator in the photopolymerization processes. The photolability of this group is due to the cleavage of the C S bond by UV irradiation. N,N‐Diethyl dithiocarbamato‐(1,2)‐propane diol with a pendent N,N‐diethyl dithiocarbamato group was prepared from 3‐chloro‐(1,2)‐propane diol and sodium diethyl dithiocarbamate. A polyurethane macrophotoinitiator was then synthesized by a two‐step process, where N,N‐diethyl dithiocarbamato‐(1,2)‐propane diol was used as the chain extender. Other components used included 4,4′‐diphenylmethane diisocyanate and poly(propylene glycol) (molecular weight = 1000). The polyurethane thus synthesized had pendent N,N‐diethyl dithiocarbamato groups. This polyurethane macrophotoinitiator was then used to polymerize methyl methacrylate in a photochemical reactor (Compact‐LP‐MP 88) at 254 nm. The resulting graft copolymer, polyurethane‐g‐poly(methyl methacrylate), was freed from the homopolymer by a standard procedure. The graft copolymer was characterized by Fourier transform infrared spectroscopy, ¹H‐NMR spectroscopy, thermogravimetric analysis, differential scanning calorimetry, solution viscometry, and scanning electron microscopy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of chemical crosslinking on the structure and mechanical properties of polyurethane prepared from copoly(PPO–THF) triols

Copoly(PPO–THF) (oxypropane–tetrahydrofuran) diol and triol were synthesized by cationic copolymerization of PPO–THF in the presence of 1,4-butanediol (BD) or 2,2′-dihydroxymethyl butanol (DHMB). The results of proton nuclear magnetic resonance verified the chemical structure of the obtained diol and triol. The amounts of the end hydroxyl group for the obtained triol and diol were measured by the end group analysis method. Linear (B-series) and crosslinked (T-series) polyurethanes were prepared from the diol and triol, respectively. The weight ratio of hard segment in the soft domain was calculated with Fourier transform infrared spectroscopy. Differential scanning calorimetry technology was used to investigate the structure of hard domains in B- and T-series polyurethanes. Mechanical properties studies of B- and T-series polyurethanes were carried out. Higher ultimate strength of T-series polyurethane than that of the B-series one was discussed. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:2163–2169, 1998     

Chemical modification of chloromethylated polysulfones via click reactions

A new approach to the modification of azidomethyl polyethersulfones using click reactions with acetylenic derivatives in the presence of CuBr as catalyst is presented. An azidomethyl polyethersulfone was prepared by the reaction of chloromethylated polysulfone with sodium azide in dimethylformamide. By the Cu(I)‐catalysed Huisgen 1,3‐dipolar cycloaddition reaction of the azidomethyl polyethersulfone to acetylenic derivatives, new polyethersulfones containing 1,2,3‐triazole rings were obtained. The structures of the polymers were confirmed using attenuated total reflectance Fourier transform infrared and NMR spectroscopy. The polymers were characterized using dynamic mechanical analysis, thermogravimetric analysis, stress‐strain and water contact angle measurements and solubility tests. The polymers bearing 1,2,3‐triazole rings having OH or COOH as substituents exhibited static contact angles smaller than that of the parent polyethersulfone. Copyright © 2010 Society of Chemical Industry     

Effect of chemical functionalization on the electrochemical properties of conducting polymers. Modification of polyaniline by diazonium ion coupling and subsequent reductive degradation

The electrochemical properties of polyaniline (PANI) can be altered by coupling the polymer with aryldiazonium ions. The ions are synthesized by diazotization of aromatic primary amines (1-aminoanthraquinone, sulphadiazine and 4-cyanoaniline) bearing functional groups which are then linked to the polyaniline backbone. All materials produced are electroactive, suggesting that the reaction involves coupling of the diazonium ion with the aromatic rings and not nucleophilic substitution by the aminic nitrogen of PANI on the aryl cations. The electrochemical properties of the modified polymers are different to those of PANI, likely due to electronic and steric effects of the attached groups. Reductive degradation of the azo linkages, using dithionite ion, removes the attached moieties leaving primary amino groups attached to the polyaniline backbone. In that way, the effect of the attached groups on the electrochemical properties of PANI is eliminated. FTIR spectroscopy measurement of the different polymers supports the proposed mechanism. Using the method a polymer containing redox (anthraquinone) groups, which could be used for charge storage, is obtained. Additionally a material containing sulphadiazine moieties, which can be released in vivo by bacterial activity, is also produced. The molecule is a well-known sulfa drug with bacteriostatic activity. The reaction sequence seems to be of general application to modify polyanilines, by attaching functional groups, and then to produce a PANI backbone bearing primary amino groups. Evidence is presented on the kinetic control of attached group removal.     

新型聚四氢呋喃多元醇的合成及表征

以丙三醇或水为共引发剂,三氟化硼乙醚（BF₃·OEt₂）为引发剂,引发四氢呋喃阳离子开环聚合,合成了一种新型聚四氢呋喃三元醇（PTHF-T）及聚四氢呋喃二元醇（PTMG/PTHF-D）。研究了丙三醇、丙三醇/水、水、反应时间等对聚合反应的影响。用傅里叶变换红外光谱法（FTIR）表征PTHF结构,凝胶渗透色谱法（GPC）、黏度法测定分子量,端基滴定法测定羟值。结果表明,不同丙三醇/水比例,可定量获得不同官能度的聚四氢呋喃多元醇（PTHF）;丙三醇为共引发剂能得到产率高且分子量分布窄的PTHF;同时得出PTHF重均分子量M_w与黏均分子量M_h的关系式。该PTHF-T可用于聚氨酯快速吸附材料的制备。     

Aqueous Dispersion and Slip Casting of Boron Carbide Powder: Effect of pH and Oxygen Content

The effect of pH and oxygen content on the zeta potential, viscosity, and casting performance of fine (>3 μm) boron carbide powder is presented. X-ray photoelectron spectroscopy of the powder revealed a surface layer of adsorbed water and oxides of boron and carbon. The soluble boric acid impurity was removed by washing the powder with water or alcohols. Electrophoresis indicated that the B₄C surface was negatively charged in water above pH 1, but the presence of dissolved boric acid suppressed the zeta potential at high pH. Stable, low-viscosity dispersions of >30 vol% solids were prepared and slip cast at pH >6, but boric acid was destabilizing for dispersions prepared above pH 7. The green density of slip-cast parts was more reproducible and about 3% to 5% higher for washed powders than for high-oxygen-content powders.     

Separation and Quantification of Vegetable Oil Based Polyols by High Performance Liquid Chromatography with Evaporative Light Scattering Detection

Polyols with terminal primary alcohol functionalities were obtained from canola oil via an ozonolysis and hydrogenation process. A high performance liquid chromatography (HPLC) method with evaporative light scattering detection (ELSD) was developed for separating and quantifying the polyol products. Linear calibration curves were obtained for the mono-ol, diol and triol components with correlations (r ²) above 0.98. According to the standard curve, the content of mono-ol, diol and triol can be obtained from their HPLC-ELSD chromatograms.