An Efficient Approach for Immobilizing the Oxo‐Vanadium Schiff Base onto Polymer Supports using Staudinger Ligation

The present paper describes the use of Staudinger ligation as an efficient and high‐yielding approach for the immobilization of oxo‐vanadium Schiff base on polymeric supports via covalent attachment under mild conditions. The described strategy is simple in use, versatile, highly efficient with respect to better catalyst loading and proceeds under mild, metal‐free conditions. The catalytic potential of the prepared polymer immobilized oxo‐vanadium Schiff bases was tested for the oxidation of sulfides using aqueous tert‐butyl hydroperoxide (TBHP) as oxidant. The polymer‐supported catalysts could easily be recovered from the reaction mixture and reused for four runs without loss in activity and no metal leaching was observed during this course.     

Heparin‐immobilized poly(2‐hydroxyethylmethacrylate)‐based microspheres

Poly(2‐hydroxyethylmethacrylate) (PHEMA)‐based microspheres (150–200 µm in diameter) were produced by a modified suspension polymerization of different type of comonomers—namely, acrylic acid, dimethylaminoethyl‐methacrylate, and methylmethacrylate. These microspheres were activated with cyanogen bromide (CNBr) at pH 11.5, and heparin molecules were then immobilized through covalent bonds. The amount of immobilized heparin was controlled by changing the initial concentration of CNBr and heparin. The increase in the initial concentrations of both CNBr and heparin caused an increase in the amount of heparin immobilized onto microspheres for all polymer surfaces. The maximum heparin immobilization was observed on the PHEMA homopolymer microspheres (180 mg/g). The plain and heparin‐immobilized microspheres were contacted with blood in in vitro systems and in ex vivo animal experiments. Loss of the blood cells and clotting times were followed. Anticoagulant effect of the immobilized heparin was clearly observed with blood coagulation experiments. Loss of cells in the blood contacting with heparin‐immobilized microspheres was significantly lower than those observed with the plain microspheres. Bovine serum albumin adsorption onto the microspheres containing heparin on their surfaces was also studied. High albumin adsorption values (up to 127 mg/g) were observed in which the heparin‐immobilized PHEMA microspheres were used. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 655–662, 1999     

Immobilization of chymotrypsin with interpolymer complexes of P(TM‐co‐AAm)/PAA

Chymotrypsin was immobilized with interpolymer complexes formed by the cationic polymer poly(allyltrimethyl ammonium chloride‐co‐acrylamide) [P(TM‐co‐AAm)] and poly(acrylic acid) (PAA). The introduction of a small amount of cationic groups led to a much stronger polymer–polymer interaction between P(TM‐co‐AAm) and PAA. The characteristic pH sensitivity of this kind of complex provided the possibilities of controlling the activity of the immobilized enzyme and separating the immobilized enzyme from the batch by changing the pH of the medium. Compared with the free enzyme, the immobilized chymotrypsin had higher thermal stability, acid–base stability, and stability in use. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2013–2018, 2001     

Polymer supported reagents. III. Kinetic study of synthesizing n‐octylacetate using insoluble titanium tetrachloride

Insoluble poly(4‐vinylpyridine‐co‐styrene) beads are prepared using divinylbenzene as the crosslinking agent. These polymer beads are converted into poly(4‐vinylpyridine‐N‐oxide) (PVPNO) under peracetic acid conditions. The resulting polymer is functionalized with titanium tetrachloride (TiCl₄) to afford the corresponding PVPNO‐TiCl₄ complex. This complex shows good catalytic activity for esterification reactions. The kinetics of formation of n‐octylacetate from acetic acid and n‐octanol is reported. The effects of stirring speed, reactant concentration, catalyst amount, percent crosslinking, particle size, and temperature on the conversion is investigated. The rate constants are found to increase with an increase in the stirring speed, concentration of n‐octanol, catalyst amount, and temperature and decrease with an increasing percentage of crosslinking and the mesh size of the polymer beads. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2075–2080, 2000     

A convenient synthesis of macroporous polymer‐supported supernucleophilic reagent and linear macromolecules

N,N′‐Bis(4‐pyridinyl)piperazine and N‐(4‐pyridinyl)piperazine have been prepared by treatment of piperazine with 4‐chloropyridine. N,N′‐Bis(4‐pyridinyl)piperazine (bis‐DMAP) is similar to a couple of 4‐(N,N‐dimethylamino)pyridine (DMAP). N‐(4‐Pyridinyl)piperazine as reactive group can be linked onto the macroporous polymeric carrier producing a polymer‐bound catalyst. A linear epoxy polymer containing the supernucleophilic functional groups have been synthesized by reaction of epichlorohydrin and 4‐aminopyridine. The linear polymeric catalysts have been braced by the macroporous resin to obtain a polymer‐supported linear polymeric catalyst. It is found that catalytic activity of bis‐DMAP approaches that of DMAP. The activity of the polymer‐supported linear polymeric catalyst is higher than that of the polymer‐bound catalyst in the acetylation of tert‐butyl alcohol, as monitored by gas–liquid chromatography. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 593–597, 2000     

Thermomechanical properties and shape memory effect of epoxidized natural rubber crosslinked by 3‐amino‐1,2,4‐triazole

A thermally induced shape memory polymer based on epoxidized natural rubber (ENR) was produced by curing the ENR with 3‐amino‐1,2,4‐triazole as a crosslinker in the presence of bisphenol‐A as a catalyst. Dynamic mechanical and tensile analysis was conducted to examine the variation of glass transition temperature, stiffness, and extensibility of the vulcanizates with the amount of curatives. Shape memory properties of the ENR vulcanizates were characterized by shape retention and shape recovery. It was revealed that the glass transition temperature of the ENR vulcanizates could be tuned well above room temperature by increasing the amount of curing agents. Also, ENR vulcanizates with T_g higher than ambient temperature showed good shape memory effects under 100% elongation, and the response temperatures of the recovery were well matched with T_g of the samples. Copyright © 2006 Society of Chemical Industry     

Liquid/solid two‐phase carbonization of low‐molecular‐weight chloro‐/bromo‐hydrocarbons

A novel liquid/solid two‐phase reaction has been discovered that enables destruction of a series of low‐molecular‐weight chloro‐/bromo‐hydrocarbons to carbon‐based materials. The solid phase is anhydrous potassium hydroxide and the liquid phase is a benzene or tetrahydrofuran solution of halide and contains a certain amount of tetrabutyl ammonium bromide (TBAB) as phase transfer catalyst. The structure of the carbon‐based materials have been characterized by elemental analysis, Fourier transform infrared (FT‐IR), FT‐Raman, and X‐ray photoelectron spectroscopies, and their morphologies have been examined by wide‐angle X‐ray diffraction and transmission electron microscopy. The results indicate that the products are amorphous nanoparticles and contain mainly elemental carbon. They consist of sp, sp², and sp³ carbon atoms simultaneously and can be regarded as carbyne analogues. This work provides a convenient method for synthesizing new carbon‐based materials in relatively high yields. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1510–1515, 2000     

UV‐cured natural polymer‐based membrane for biosensor application

Chitosan, a natural product, is inherently biodegradable, biocompatible, and nontoxic. These properties make chitosan ideal for inclusion in matrices designed for use in enzyme immobilization for clinical analysis. This study demonstrates the feasibility of using chitosan in electrochemical biosensor fabrication. The enzyme sulfite oxidase (SOX) was covalently immobilized onto the matrix of chitosan–poly(hydroxyethyl methacrylate) (chitosan–pHEMA), a natural/synthetic polymer hybrid obtainable via UV curing. p‐Benzoquinone, which served as an electron transfer mediator, was coupled onto the polymer network for activation of the chitosan–pHEMA copolymer, after completion of the photo‐induced polymerization reaction. The biological activity of the immobilized SOX and the electroactivity of the coupled p‐benzoquinone were investigated. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 466–472, 2001     

Kinetic study on peroxidation of benzaldehyde by polymer‐immobilized cobalt‐EDTA complex

Polymer‐immobilized cobalt‐EDTA complex was prepared by grafted copolymerization of methacrylic acid (MAA) and acrylonitrile (AN initiated by redox initiation of EDTA‐2Na (Ethylenediamine tetraacetic acid disodium salt) with ceric ion (Ce²⁺)). High yield and selectivity for peroxidation of benzaldehyde were obtained when using the polymer‐immobilized cobalt‐EDTA complex as a catalyst. With the concentration of benzaldehyde increasing, the concentration of perbenzoic acid was increased from 0.38M to 0.98M, but yield of perbenzoic acid decreased from 0.76M to 0.65M. With the amount of the polymer support increased, the yield of perbenzoic acid increased from 70% to 82%. The selectivity remained about 82% in the various amounts of the polymer support. The activation energy of peroxidation of benzaldehyde was 43.4 KJ/mole. The expression of the reaction rate was: r_i = k[RCHO][polymer support]^0.5. A mechanism for peroxidation of benzaldhyde catalysed by polymer‐immobilized cobalt‐EDTA complex was proposed in this investigation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3248–3257, 2001     

Chemical modification of chloromethylated polystyrene with pyridylazo‐β‐naphthol

Chloromethylated polystyrene was chemically modified through alkylation of pyridylazo‐β‐naphthol (PAN) in the presence of a phase‐transfer catalyst. The chemical modification was achieved through O‐alkylation as well as N‐alkylation of PAN, leading to formation of polymer‐supported quaternary ammonium salt in the latter case. Both types of a polymer‐supported PAN moiety were detected by FTIR spectroscopic analysis. The complexation behavior of the polymer‐supported PAN as an ion‐exchanger toward some metal ions was studied. Thermogravimetric and differential thermogravimetric analyses data were used to study the kinetics of the thermal decomposition process of the ion‐exchanger. Some thermodynamic parameters for the ion‐exchanger were calculated by applying the rate theory of the first‐order reaction. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3044–3048, 2000     

Pd nanoparticles supported on hydrotalcite‐modified porous alumina spheres as selective hydrogenation catalyst

The immobilization or supporting of transition‐metal nanoparticles on carriers by different techniques has attracted much attention, considering the significance of nanocatalysts in actual practical applications. Here we report Pd nanoparticles supported on modified porous θ‐alumina spheres are adopted as heterogeneous catalysts for the selective hydrogenation of dimethyl terephthalate (DMT) to dimethyl cyclohexane‐1,4‐dicarboxylate (DMCD), a kind of significant polymer modification and intermediate. θ‐alumina spheres as supports were originally modified by in situ growth of magnesium‐aluminum layered double hydroxide (MgAl‐LDH; also known as hydrotalcite) in the pores and on the surface. Pd nanoparticles were immobilized on the supports by a subsequent wet impregnating method. The resulting Pd nanoparticles catalyst provides quite higher activity/selectivity compared with that supported on the unmodified alumina spheres with the same loading of Pd. The enhanced catalytic performance of the former can be ascribed to the higher dispersion of Pd nanoparticles and the smaller particle size. © 2011 American Institute of Chemical Engineers AIChE J, 58: 1853–1861, 2012     

Palladium Nanoparticles Immobilized on Nano‐Silica Triazine Dendritic Polymer (Pdnp‐nSTDP): An Efficient and Reusable Catalyst for Suzuki–Miyaura Cross‐Coupling and Heck Reactions

A new catalyst based on palladium nanoparticles immobilized on nano‐silica triazine dendritic polymer (Pd_np‐nSTDP) was synthesized and characterized by FT‐IR spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy, energy dispersive X‐ray, transmission electron microscopy and elemental analysis. The size of the palladium nanoparticles was determined to be 3.1±0.5 nm. This catalytic system showed high activity in the Suzuki–Miyaura cross‐coupling of aryl iodides, bromides and chlorides with arylboronic acids and also in the Heck reaction of these aryl halides with styrenes. These reactions were best performed in a dimethylformamide (DMF)/water mixture (1:3) in the presence of only 0.006 mol% and 0.01 mol% of the catalyst, respectively, under conventional conditions and microwave irradiation to afford the desired coupling products in high yields. The Pd_np‐nSTDP was also used as an efficient catalyst for the preparation of a series of star‐ and banana‐shaped compounds with a benzene, pyridine, pyrimidine or 1,3,5‐triazine unit as the central core. Moreover, the catalyst could be recovered easily and reused several times without any considerable loss of its catalytic activity.     

Blending ultrahigh‐molecular‐weight polyethylene and poly(ethylene/10‐undecen‐1‐ol) in one nascent particle

Ultrahigh‐molecular‐weight polyethylene (UHMWPE)/polar polyethylene (PE) composites were blended in one nascent particle by in situ polymerization with a hybrid catalyst. Polystyrene‐coated SiO₂ particles were used to support the hybrid catalyst. Fe(acac)₃/2,6‐bis[1‐(2‐isopropylanilinoethyl)] was supported on SiO₂ for the synthesis of UHMWPE, whereas [PhN?C(CH₃)CH?C(Ph)O]VCl₂ was immobilized on a polystyrene layer to prepare a copolymer of ethylene and 10‐undecen‐1‐ol (polar PE). Importantly, the core part of the supports (the polystyrene layer) exhibited pronounced transfer resistance to 10‐undecen‐1‐ol; this provided an opportunity to keep the inside iron active sites away from the poisoning of 10‐undecen‐1‐ol. Therefore, UHMWPE was simultaneously synthesized with polar PE by in situ polymerization. Interestingly, the morphological results show that UHMWPE and the polar PE were successfully blended in one nascent polymer. This improved the miscibility of the composites, where most of the chains were difficult to crystallize because of the strong interactions between the PE chains and polar chains. The blends showed an extremely low crystallinity, that is, 9.9%. Finally, the hydrophilic properties of the polymer composites were examined. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46652.     

Synthesis and characterization of water soluble poly(N‐acetyl)iminoethylene and poly(ethyleneimine) by ion‐exchanged clay montmorillonite

The cationic polymerization of 2‐méthyl‐2‐oxazoline was carried out at 0°C in acetonitrile using an acid‐exchanged montmorillonite as acid solid ecocatalyst (Maghnite‐H⁺). The effect of the amount of catalyst, solvent, and times of polymerization on yield and viscosity of polymer was studied. A typical reaction product (PMOX) was analyzed by infrared and nuclear magnetic resonance spectroscopy as well as by gel‐permeation chromatography and MALDI‐TOF MS. The polymers presented similar spectrometric results and narrow molecular weight distribution. The poly(N‐acetyl)iminoethylene was hydrolyzed in acid medium obtaining a linear poly(ethyleneimine). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3741–3750, 2006     

Monolith‐ and Silica‐Supported Carboxylate‐Based Grubbs–Herrmann‐Type Metathesis Catalysts

The synthesis of silica‐ and monolith‐supported Grubbs–Herrmann‐type catalysts is described. Two polymerizable, carboxylate‐containing ligands, exo, exo‐7‐oxanorborn‐2‐ene‐5,6‐dicarboxylic anhydride and 7‐oxanorborn‐2‐ene‐5‐carboxylic acid were surface‐immobilized onto silica‐ and ring‐opening metathesis (ROMP‐) derived monolithic supports using “grafting‐from” techniques. The “1^st generation Grubbs catalyst”, RuCl₂(CHPh)(PCy₃)₂, was used for these purposes. In addition, a poly(norborn‐2‐ene‐b‐exo, exo‐norborn‐2‐ene‐5,6‐dicarboxylic anhydride)‐coated silica 60 was prepared. The polymer supported anhydride and carboxylate groups were converted into the corresponding mono‐ and disilver salts, respectively, and reacted with the Grubbs–Herrmann catalyst RuCl₂(CHPh)(IMesH₂)(PCy₃) [IMesH₂=1,3‐bis(2,4,6‐trimethylphenyl)‐4,5‐dihydroimidazol‐2‐ylidene]. Heterogenization was accomplished by exchange of one chlorine ligand with the polymeric, immobilized silver carboxylates to yield monolith‐supported catalysts 4, 5 , and 6 as well as silica‐supported systems 7, 8 and 9 . The actual composition of these heterogenized catalysts was proven by the synthesis of a homogeneous analogue, RuCl[7‐oxanorbornan‐2‐(COOAg)‐3‐COO](CHPh)(IMesH₂)(PCy₃) ( 3 ). All homogeneous and heterogeneous catalysts were used in ring‐closing metathesis (RCM) of diethyl diallylmalonate, 1,7‐octadiene, diallyldiphenylsilane, methyl trans‐3‐pentenoate, diallyl ether, N,N‐diallyltrifluoracetamide and t‐butyl N,N‐diallylcarbamate allowing turnover numbers (TON's) close to 1000. In a flow‐through set‐up, an auxiliary effect of pendant silver carboxylates was observed with catalyst 5 , where the silver moiety functions as a (reversible) phosphine scavenger that both accelerates initiation and stabilizes the catalyst by preventing phosphine elution. Detailed catalytic studies were carried out with the monolith‐supported systems 4 and 6 in order to investigate the effects of temperature and chain‐transfer agents (CTA's) such as cis‐1,4‐diacetoxybut‐2‐ene. In all RCM experiments Ru‐leaching was low, resulting in a Ru‐content of the RCM products ≤3.5 μg/g (3.5 ppm).     

Aminated poly‐N‐vinylformamide as a modern retention aid of alkaline paper sizing with acid rosin sizes

Partially aminated poly‐N‐vinylformamides (APNVF) were prepared by the hydrolysis of PNVF and used as the retention aid of rosin size. The dual retention aids system, consisting of this modern polymer and aluminum sulfate (alum) for neutral‐alkaline paper sizing using acid rosin sizes, was evaluated by experiment. The results indicated that APNVF was very effective and a small amount of the polymer used together with alum considerably increased the size retention and sizing degree of paper under neutral‐alkaline conditions. The cationic charge density of APNVF significantly influenced the sizing efficiency of the rosin sizes. Furthermore, the retention of alkaline filler CaCO₃ and paper strength were improved by the polymer addition. It is clear that the polymer can be used as a multifunctional additive for papermaking. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1805–1810, 2000     

Preparation of high isotactic polybutene‐1

Polymerization of butene‐1 (B‐1) was carried out with a PP‐TiCl₃/Et₂AlCl/methyl methacrylate (MMA) catalyst system in n‐heptane. The influence of temperature, pressure, time and H₂ on molecular weight, isotacticity, and catalytic activity were studied by viscometry, solubility in boiling diethyl ether, and measuring the polymer produced, respectively. The structural properties of the isotactic polybutene‐1 (IPB‐1) were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and melt flow index (MFI). The molecular weight of the products can be controlled by H₂. It was found that the catalyst showed high isotacticity and activity. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2533–2539, 2000     

Highly Enantioselective Epoxidation of Unfunctionalized Olefins Catalyzed by Chiral Jacobsen’s Catalyst Immobilized on Phenoxy‐Modified Zirconium Poly(syrene‐phenylvinylphos‐ phonate)phosphate

Chiral Jacobsen’s catalyst was axially immobilized onto phenoxy‐modified zirconium poly(styrene‐phenylvinylphosphonate)phosphate (ZPS‐PVPA). The immobilized catalysts show comparable ee values for asymmetric epoxidation of styrene and much higher ee values for α‐methylstyrene (73.7% vs. 54.0%) and indene (99.9% vs. 65.0%) than the homogeneous Jacobsen’s catalyst. Moreover, the as‐synthesized catalysts are relatively stable and can be recycled at least five times without significant loss of activity and enantioselectivity. A point worth emphasizing is that the heterogeneous catalysts afforded remarkable increases of conversion and ee values in the absence of expensive O‐coordinating axial bases for the asymmetric epoxidation of olefins, especially for the epoxidation of α‐methylstyrene (conversion: from 24.3% to 99.9%; ee: from 29.4% to 73.7%), which may overcome the last obstacle for the potential industry application of chiral Jacobsen’s catalyst.     

Synthesis and characterization of temperature‐sensitive block copolymers from poly(N‐isopropylacrylamide) and 4‐methyl‐ε‐caprolactone or 4‐phenyl‐ε‐caprolactone

This study synthesizes thermally sensitive block copolymers poly(N‐isopropylacrylamide)‐b‐poly(4‐methyl‐ε‐caprolactone) (PNIPA‐b‐PMCL) and poly(N‐isopropylacrylamide)‐b‐poly(4‐phenyl‐ε‐caprolactone) (PNIPA‐b‐PBCL) by ring‐opening polymerization of 4‐methyl‐ε‐caprolactone (MCL) or 4‐phenyl‐ε‐caprolactone (BCL) initiated from hydroxy‐terminated poly(N‐isopropylacrylamide) (PNIPA) as the macroinitiator in the presence of SnOct₂ as the catalyst. This research prepares a PNIPA bearing a single terminal hydroxyl group by telomerization using 2‐hydroxyethanethiol (ME) as a chain‐transfer agent. These copolymers are characterized by differential scanning calorimetry (DSC), ¹H‐NMR, FTIR, and gel permeation chromatography (GPC). The thermal properties (T_g) of diblock copolymers depend on polymer compositions. Incorporating larger amount of MCL or BCL into the macromolecular backbone decreases T_g. Their solutions show transparent below a lower critical solution temperature (LCST) and opaque above the LCST. LCST values for the PNIPA‐b‐PMCL aqueous solution were observed to shift to lower temperature than that for PNIPA homopolymers. This work investigates their micellar characteristics in the aqueous phase by fluorescence spectroscopy, transmission electron microscopy (TEM), and dynamic light scattering (DLS). The block copolymers formed micelles in the aqueous phase with critical micelle concentrations (CMCs) in the range of 0.29–2.74 mg L^?1, depending on polymer compositions, which dramatically affect micelle shape. Drug entrapment efficiency and drug loading content of micelles depend on block polymer compositions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Ring‐opening copolymerization of maleic anhydride with propylene oxide by double‐metal cyanide

Ring‐opening copolymerization of maleic anhydride (MA) with propylene oxide (PO) was successfully carried out by using double‐metal cyanide (DMC) based on Zn₃[Co(CN)₆]₂. The characteristics of the copolymerization are presented and discussed in this article. The structure of the copolymer was characterized with IR and ¹H‐NMR. Number‐average molecular weight (M_n) and molecular weight distribution (MWD) of the copolymer were measured by GPC. The results showed that DMC was a highly active catalyst for copolymerization of MA and PO, giving high yield at a low catalyst level of 80 mg/kg. The catalytic efficiency reached 10 kg polymer/g catalyst. Almost alternating copolymer was obtained when monomer charge molar ratio reached MA/PO ≥ 1. The copolymerization can be also carried out in many organic solvents; it was more favorable to be carried in polar solvents such as THF and acetone than in low‐polarity solvents such as diethyl ether and cyclohexane. The proper reaction temperature carried in the solvents was between 90 and 100 °C. The M_n was in the range of 2000–3000, and it was linear with the molar ratio of conversion monomer and DMC catalyst. The reactivity ratio of MA and PO in this reaction system was given by the extended Kelen–Tudos equation: η=[r₁+(r₂/α)]ξ?(r₂/α) at some high monomer conversion. The value of reactivity ratio r₁(MA) = 0 for MA cannot be polymerized itself by DMC catalyst, and r₂(PO) = 0.286. The kinetics of the copolymerization was studied. The results indicated that the copolymerization rate is first order with respect to monomer concentration. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1788–1792, 2004