Reaction Of Poly Research Articles

Macroporous monoliths for biodegradation study of polymer particles considered as drug delivery systems

Nanostructures based on biodegradable polymers are often considered as drug delivery systems. The properties of these nanomaterails towards in vitro biodegradation are very important and usually are studied using the model physiological conditions. In this work the novel approach based on application of monolithic immobilized enzyme reactors (IMERs) as the systems for biodegradation study of the nanoobjects of different nature and morphology was suggested. Rigid nanospheres based on poly(lactic acid) and self-assembled nanoobjects formed from block-copolymer of glutamic acid and phenylalanine were applied as model nanomaterials. For that, two enzymes, namely, esterase and papain were chosen for preparation of the monolithic IMERs. The properties of immobilized enzymes were compared to those obtained for soluble biocatalysts in the reaction of poly(lactic acid) and poly(glutamic acid) degradation. The monitoring of substrate destruction process was carried out using different HPLC modes (anion-exchange, cation-exchange or precipitation-redissolution based process) also based on application of the same modern stationary phase, namely, macroporous monoliths (CIM disks and lab-made column). Finally, the applicability of monolithic immobilized enzyme reactors for degradation of polyester and polypetide-based particles was demonstrated and compared to the process observed in human blood plasma.

Modification of poly(vinyl chloride) with sodium salts of triazoles

New copolymers containing reactive vinyltriazole units and polyvinylene blocks with conjugation system promising as materials with special electrical, physical, catalytic, and sorption properties have been prepared by the reaction of poly(vinyl chloride) with sodium salts of 1,2,4-triazole and 1,2,3-benzotriazole in a dimethylformamide medium.

Computational and Experimental Investigation of Immobilization of CuI Nanoparticles on 3-Aminopyridine Modified Poly(styrene-co-maleic anhydride) and Its Catalytic Application in Regioselective Synthesis of 1,2,3-Triazoles

Cu(I) nanoparticles (NPs) on modified poly(styrene-co-maleic anhydride) was prepared via a facile procedure. In this regard the modified co-polymer (SMA) was initially synthesized from the reaction of poly(styrene-co-maleic anhydride) with 3-aminopyridine. Upon the treatment of CuI with SMA, Cu(I) NPs were immobilized on SMA. This immobilized Cu(I) NPs was fully characterized by FTIR, SEM and EDAX analysis methods. Moreover, the interaction of Cu cations with 3-aminopyridine modified SMI catalyst via density functional theory (DFT) and quantum theory of atoms in molecules (QTAIM) computationally was studied. Our calculated results demonstrated that among 2,3 and 4 substituted aminopyridines for the modification of SMA, the 3-amnopyridine has the weakest ligand and Cu(I) interaction. However, the SMI image showed a suitable size of nanoparticles and inductively coupled plasma (ICP) analysis showed a higher Cu content in comparison with those of 2 and 4-substituted pyridines. The catalytic activity and reusability of this nanocatalyst system of 3-substituded aminopyridines was examined in the Huisgen 1,3-dipolar cycloaddition via click reaction. The reactions proceeded smoothly leading to regioselective synthesis of 1,4-disubstitued 1,2,4-triazole derivatives in excellent yields under mild reaction conditions. This heterogeneous catalytic system was separated easily by simple filtration and was reused without pre-activation at least in five runs without appreciable loss in its activity.

Assessing Chemical Transformation of Reactive, Interfacial Thin Films Made of End-Tethered Poly(2-vinyl-4,4-dimethyl azlactone) (PVDMA) Chains

Designing thin films or surface scaffolds with an appropriate display of chemical functionality is useful for biomedical applications, sensing platforms, adhesives, and barrier coatings. Relationships between the structural characteristics of model thin films based on reactive poly(2-vinyl-4,4-dimethyl azlactone) (PVDMA) brushes and the amount and distribution of primary amines used to chemically functionalize these layers in situ are quantitatively detailed via neutron reflectometry and compared with results from ellipsometry. After functionalization, the PVDMA brush thickness increases as a result of the primary amines reacting with the azlactone rings. Both techniques show that the extent of functionalization by small-molecule amines depends on the size of the amine, the grafting density of brush chains, and their molecular weight. However, constrained analysis of neutron reflectivity data predicated on that technique’s sensitivity to isotopic substitution and its ability to resolve structure at the na...

A reactive poly(styrene sulfonic acid) catalyst preparation and usage for fuel additive ester production

The production of new generation fuels from sustainable resource is prominent issue of the current world. A wide range of feedstock can be used to produce first generation liquid fuel from starch to corn. Besides the first one, second generation fuel is considered as fuel additive for increasing the calorific value of gasoline and limiting the hazardous gas emission. Only small amount usage of lignocellulosic based additives such as ethyl valerate (EV) increases the energy density of fuel. Due to the non-hazardous and less irritant properties of ethyl valerate it is defined as “green fuel”. It was reported that the 10-20% blend ratio of EV with gasoline causes a significant improvement for engine performance. EV is chemically produced by esterification reaction between ethanol and valeric acid. Reaction can be carried out by means of heterogeneous, homogeneous acid catalyst, lipase and ionic liquids and reactive polymers. In this study, a reactive poly (styrene sulfonic acid) (PSSA) catalyst was prepared and used for ethyl valerate synthesis at different temperature conditions. Effect of alcohol:acid feed molar ratio was also investigated as a function of acid conversion. Better results were obtained as 77.9 % acid conversion at 343 K when alcohol:acid feed molar ratio was 4:1

Synthesis of Optically Active Poly(diphenylacetylene)s Using Polymer Reactions and an Evaluation of Their Chiral Recognition Abilities as Chiral Stationary Phases for HPLC.

A series of optically active poly(diphenylacetylene) derivatives bearing a chiral substituent (poly-2S) or chiral and achiral substituents (poly-(2Sx-co-31−x)) on all of their pendant phenyl rings were synthesized by the reaction of poly(bis(4-carboxyphenyl)acetylene) with (S)-1-phenylethylamine ((S)-2) or benzylamine (3) in the presence of a condensing reagent. Their chiroptical properties and chiral recognition abilities as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) were investigated. Poly-2S and poly-(2Sx-co-31−x) (0.06 < x < 0.71) formed a preferred-handed helical conformation with opposite helical senses after thermal annealing despite possessing the same chiral pendant (h-poly-2S and h-poly-(2Sx-co-31−x)). Furthermore, h-poly-2S and h-poly-(2S0.36-co-30.64) emitted circularly polarized luminescence with opposite signs. h-Poly-2S showed higher chiral recognition abilities toward a larger number of racemates than poly-2S without a preferred-handed helicity and the previously reported preferred-handed poly(diphenylacetylene) derivative bearing the same chiral substituent on half of its pendant phenyl rings. h-Poly-(2S0.36-co-30.64) also exhibited good chiral recognition abilities toward several racemates, though the elution order of some enantiomers was reversed compared with h-poly-2S.

Reactive Copolymers Based on N-Vinyl Lactams with Pyridyl Disulfide Side Groups via RAFT Polymerization and Postmodification via Thiol–Disulfide Exchange Reaction

Herein, we report the synthesis of a series of novel pyridyl disulfide (PDS)-functionalized statistical reactive copolymers that enable facile access to complex polymeric architectures through highly selective thiol–disulfide exchange reaction with thiol-containing ligands or proteins. Functional reactive poly(N-vinyl lactam)-based copolymers including poly(N-vinylpyrrolidone-co-pyridyl disulfide ethyl methacrylate) (PVPD), poly(N-vinylpiperidone-co-pyridyl disulfide ethyl methacrylate) (PVPID), and poly(N-vinylcaprolactam-co-pyridyl disulfide ethyl methacrylate) (PVD) with PDS side groups were synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization at 60 °C in anisole with methyl 2-(ethoxycarbonothioylthio)propanoate as chain transfer agent. The PDS contents in the synthesized copolymers were varied from 2 to 10 mol % (as confirmed by systematical characterization with FTIR/Raman and 1H NMR spectroscopy) using well-controlled continuous feeding method. The kinetics study suggested that copolymerizations were less favored with the enlargement of the lactam rings, indicated by lower conversions and larger dispersity indexes (Đ). The PDS-functionalized reactive polymers were amenable to functionalization with a variety of thiol-containing molecules, including 3-mercaptopropionic acid (3M), 2-phenylethanethiol (2P), methyl 3-mercaptopropionate (M3), 2-mercaptoethanol (2M), 2-aminoethanethiol (2A), poly(ethylene glycol) methyl ether thiol (PEG-SH), and enhanced green fluorescent protein (EGFP) via thiol–disulfide exchange reaction under mild conditions, confirmed by 1H NMR and SDS-PAGE. The conversions in all cases were higher than 95%, displaying that the thiol–disulfide exchange reaction to PDS groups with thiol-containing molecules is highly selective and tolerant to different ligands including amine, carboxyl, hydroxyl, phenyl, PEG and even polypeptides, providing a versatile scaffold for facile conjugation of various biological components. The contact angle measurement results and fluorescence microscopy study indicated that the reactive films based on the PDS-functionalized copolymers allowed facile, direct, and environmental-friendly surface engineering of surfaces from aqueous solution suggesting potential application in surface decoration of tissue-engineering scaffolds and medical implants. The initial cell culture experiments with HeLa cells displayed that the unmodified PVPD film was nontoxic and biocompatible while the film modified with PEG (a type of antifouling polymer) showed diminished cell attachment and growth, indicating that elegant engineering of the film surface can meet demands of particular applications.

A Reactive Platform Approach for the Rapid Synthesis and Discovery of High χ/Low N Block Polymers

We report a reactive polymer platform for the rapid discovery of strongly segregated diblock polymers that microphase separate into well-defined morphologies with sub-5 nm features. Our strategy employs reactive poly(styrene-block-2-vinyl-4,4-dimethylazlactone) (SV) polymers with low degrees of polymerization (N), in which the V blocks undergo selective and quantitative reactions with functional primary amines, to identify new poly(acrylamides) that are highly immiscible with poly(styrene) and induce block polymer self-assembly. Using a combination of optical birefringence and small-angle X-ray scattering (SAXS), we characterize a library of 17 block polymers produced by amine functionalization of four parent SV diblocks synthesized by sequential RAFT polymerizations. We demonstrate that V block functionalization with hydroxy- and methoxy-functional amines yields diblocks that order into lamellar mesophases with half-pitches as small as 3.8 nm. Thus, this azlactone-based reactive molecular platform enable...

Thermal, morphological, mechanical and aging properties of polylactide blends with poly(ether urethane) based on chain-extension reaction of poly(ethylene glycol) using diisocyanate

Poly(ether urethane)s (PEU), including PEUI15 and PEUH15, were prepared through chain-extension reaction of poly(ethylene glycol) (PEG-1500) using diisocyanate as a chain extender, including isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI). These PEUs were used to toughen polylactide (PLA) by physical and reactive blending. Thermal, morphological, mechanical and aging properties of the blends were investigated in detail. These PEUs were partially compatible with PLA. The elongation at break of the reactive blends in the presence of triphenyl phosphate (TPP) for PLA with PEUH15 or PEUI15 was much higher than that of the physical blends. The aging test was carried out at -20 °C for 50 h in order to accelerate the crystallization of PEUs. The PEUs in the PLA/PEU blends produced crystallization and formed new phase separation with PLA, resulting in the declined toughness of blends. Fortunately, under the aging condition, although PEUH15 in blends could also form crystallization, the reactive blend of PLA/PEUH15/TPP(80/20/2) had higher toughness than the other blends. The elongation at break of PLA/PEUH15/TPP(80/20/2) dropped to 287% for the aging blend from 350% for the original blend. The tensile strength and modulus of PLA/PEUH15/TPP blend did not change obviously because of the crystallization of PEUH15.

Fluoroalkylation of poly(cyclopentadienyl)siloxane and the surface properties of poly(fluorocyclopentenyl)siloxane films

GRAPHICAL ABSTRACT

Synthesis and characterization of a new iminodiacetate chelating resin for removal of toxic heavy metal ions from aqueous solution by batch and fixed bed column methods

New porous chelating resin beads CPN-IDA were prepared by the reaction of poly (acrylonitrile-co-N,N'- methylenebisacrylamide) with etheylenediamine and sodium chloroacetate, respectively. The composition and morphology of the chelating resin was characterized by Fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA and DrTGA), scanning electron microscopy (SEM),surface area measurements by N2adsorption (SBET) and water regain (w%). Batch adsorption experiments were employed to study the impact of some factors that control the adsorption of metal ions including solution pH, concentration of metal ions, contact time and the temperature of the solution. Batch sorption results showed that the chelating resin had high affinity towards Cu(II), Cd(II) and Pb(II). The saturated adsorption capacity at 25 oC was 2.43, 1.93 and 1.45mmolg−1 resin for Cu(II), Cd(II) and Pb(II), respectively. Among the empirical isotherm models, the equilibrium adsorption results were obviously fitted with Langmuir model. The kinetics was analyzed using pseudo-first-order, pseudo-second-order, and intra-particle diffusion equations. The adsorption kinetic data were well elucidated with pseudo-second-order kinetic model. Thermodynamic parameters were calculated for the uptake of the metal ions under study and it was found to be a spontaneous process. Moreover, the adsorption of metal ions has been studied using column technique. The regeneration of CPN-IDA was experimentally performed by using nitric acid. The chelating resin was used repeatedly for five times with a little decrease in sorption of metal ions.

New reactive poly(ionic liquid)s synthesized by polymer analogous conversion of maleic anhydride containing polymers

New poly(ionic liquids) were synthesized by a two stage polymer analogous reaction. In the first stage, the reactive maleic anhydride groups of the starting polymer were converted with 1-(3-aminopropyl)-imidazole. The second stage comprises an alkylation reaction of the imidazole groups with various alkylbromides. This approach allowed tailoring of the polymer properties to a large extent. With the degree of conversion, the number of reactive groups remaining in the polymer could be adjusted. The possibility to preserve reactive groups opens new applications of the poly(ionic liquid)s as reactive blend components. As an example, reactive mixtures with bromobutyl rubber were prepared which exhibited pronounced self-healing properties.

New organosilicon derivatives of some analytical reagents: sorbents and metallochromic agents

A synthesis of organosilicon monomeric and polymeric derivatives of 1,4-phenylenediamine, 4-aminoantipyrine, and aniline, which are analytical agents possessing sorption properties, was accomplished. The synthesized organosilicon polymers were studied as sorbents of heavy metals FeIII, HgII and noble metals AgI, AuIII, RhIII, PdII, PtIV. Poly[(3-N-silsesquioxanylpropyl-4aminoantipyrine)] exhibited high sorption activity with respect to platinum group metals in comparison with poly[N,N´-bis(3-silsesquioxanylpropyl)-1,4-phenylenediamine]. The reaction of poly[(3-N-silsesquioxanylpropyl-4-aminoantipyrine)] practically with all the elements under study was accompanied by coloring. The starting monomer exhibited similar metallochromic properties.

Synthesis and characterization of waterborne polyurethane emulsions based on poly(butylene itaconate) ester

Waterborne polyurethane (WPU) prepolymer was synthesised by the reaction of poly(butylene itaconate) ester (PBI, Mn = 1109 g/mol), 1,6-hexanediol, dimethylol propionic acid (DMPA), 2,4-toluene diisocynate (TDI), hydroxyethyl acrylate (HEA), and absolute ethanol as blocking agent, triethylamine as neutralizer. Cross-linked WPU was synthesized by trimethylolpropane (TMP) as crosslinker. The influences of PBI, DMPA, and TMP content on WPU emulsions and films were investigated. The structure of WPU was determined by Fourier transform infrared (FTIR) spectra, thermal properties and glass transition temperature of WPU films were determined by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively, and morphology of the emulsion particles was observed by transmission electron microscopy (TEM). Through TGA, the heat resistance of the cross-linked WPU film was better than WPU film. By DSC analysis, glass transition temperature of cross-linked WPU film (21 °C) was higher than WPU film (10 °C).

Characterization and Properties of Reactive Poly (Lactic Acid)/Ethylene–Vinyl Alcohol Copolymer Blends with Chain-Extender

A hydrophilic copolymer, ethylene–vinyl alcohol (EVOH), was incorporated into the poly(lactic acid) (PLA) matrix to improve the barrier property of PLA through twin-screw extrusion rather than the typical coextrusion process. A chain extender, poly[(ethylene)-co-(methyl acrylate)-co-(glycidyl methacrylate)] (PEMG), was used to reduce the probability of the thermal degradation of PLA during melt compounding. Biaxial stretching was used to enhance the microstructure and barrier property of PLA-PEMG/EVOH films. Experimentally, PEMG considerably reduced the probability of the thermal degradation of the PLA-PEMG sample. Biaxial stretching increased the tensile strength and decreased the value of elongation at break of the PLA-PEMG/EVOH80 (PLA/EVOH 100/80) film. Because of the efficient blending of PLA/EVOH in the twin-screw extruder, the dispersion of EVOH in the PLA matrix revealed homogeneous dispersion with a domain size of 1–5 μm. EVOH effectively improved the water vapour transmission rate (WVTR) of PLA through melt blending. Blending PLA-PEMG with EVOH substantially decreased the WVTR from 250 cc—20 μm/m2-day-atm for neat PLA to approximately 65 cc—20 μm/m2-day-atm for the PLA-PEMG/EVOH80 film, a decrease of approximately 74 % compared with neat PLA. Moreover, the WVTR decreased further from 65 cc—20 μm/m2-day-atm for the unstretched PLA-PEMG/EVOH80 film to 6.3 cc—20 μm/m2-day-atm for the film stretched at a stretch ratio of 3.5 × 3.5 and at 100 %/s, a decrease of approximately 90 % compared with neat PLA.

Immobilized Pd on (S)‐methyl histidinate‐modified multi‐walled carbon nanotubes: a powerful and recyclable catalyst for Mizoroki–Heck and Suzuki–Miyaura C–C cross‐coupling reactions in green solvents and under mild conditions

A stable and powerful heterogeneous palladium catalyst was synthesized using immobilized palladium on (S)‐methyl histidinate bonded onto the surface of multi‐walled carbon nanotubes. The catalyst was characterized using a combination of Fourier transform infrared and X‐ray photoelectron spectroscopies, transmission electron microscopy, X‐ray powder diffraction and inductively coupled plasma, thermogravimetric and elemental analyses. This new air‐ and moisture‐stable phosphine‐free palladium catalyst was found to be highly active and reusable in Mizoroki–Heck and Suzuki–Miyaura cross‐coupling reactions in poly(ethylene glycol) and aqueous ethanol as green solvents using an extremely small amount of palladium under mild conditions. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Penetration and exchange kinetics of primary alkyl amines applied to reactive poly(pentafluorophenyl acrylate) thin films

We investigated the mechanism of primary amine-induced post-polymerization modification of active ester polymer thin films composed of pentafluorophenyl acrylate (PFPA) polymers. The most important physical parameters in the post-polymerization modification are the molecular weight of the PFPA polymers and the aliphatic chain length of the primary amines. The effects of these two parameters on the penetration depth, as well as the exchange kinetics were systematically studied by neutron reflectivity and quartz crystal microbalance with dissipation, accompanied by the measurement of surface morphological changes by an atomic-force microscopy and optical microscopy. The spin-cast PFPA polymer thin films showed distinctive differences in the exchange kinetics, as well as the penetration depth of amines as a function of the PFPA polymer molecular weight. The aliphatic chain length of primary alkyl amines markedly influenced the penetration kinetics into low-molecular weight poly(PFPA) films, whereas there was no significant penetration effect on the high-molecular weight films. The high-molecular weight of the poly(PFPA) films led to the deceleration of the dissolution of amine-functionalized polymer chains in a good solvent. The results of this study may provide a good physical background for developing reactive poly(PFPA) thin film platforms based on simple and quantitative post-modification with amine-containing molecules. The poly(pentafluorophenyl acrylate) thin film provides a reactive surface platform through facile post-modification with primary alkyl amines. We report the effect of the most important parameters in this reaction, molecular weight of the reactive polymers and the aliphatic chain length of primary amines, on the degree of exchange of the thin films. The studies with neutron reflectivity and quartz crystal microbalance offer physical backgrounds for developing versatile functional thin films based on this chemistry, in terms of penetration and exchange kinetics as a function of molecular weight of reactive ester polymers and primary amines.

Design of Thermoresponsive Polymers with Aqueous LCST, UCST, or Both: Modification of a Reactive Poly(2-vinyl-4,4-dimethylazlactone) Scaffold

The synthesis and aqueous solution properties of a family of zwitterionic homo-, co-, and terpolymers derived from poly(2-vinyl-4,4-dimethylazlactone) (pVDMA) with tunable lower and upper critical solution temperatures (LCST and UCST) are presented. A RAFT-made pVDMA precursor was reacted with mixtures of zwitterionic sulfopropylbetaine (SPB) amine or sulfobutylbetaine (SBB) amine, tetrahydrofurfurylamine (THF amine), and benzylamine (Bz amine) in varying molar ratios. Products were characterized by variable temperature (VT) NMR spectroscopy, FT-IR spectroscopy, size exclusion chromatography, turbidity, and VT dynamic light scattering in order to confirm quantitative postpolymerization modification, determine molar compositions, and elucidate structure–property relationships. Polymers comprising large molar fractions of THF groups showed LCST behavior due to a polarity change of the THF-functional segments, while SPB/SBB-rich samples, including the zwitterionic homopolymers, showed UCST behavior in ultrap...

Stress analysis of the circumferential and burst strength test in small diameter vascular grafts of segmented polyurethanes based on amino acids of L-arginine and L-lysine

Event Abstract Back to Event Stress analysis of the circumferential and burst strength test in small diameter vascular grafts of segmented polyurethanes based on amino acids of L-arginine and L-lysine Omar Castillo1, Cesar Pérez-Aranda1, 2, Francis Avilés1, Juan Cauich-Rodríguez1 and Diego Mantovani3 1 Centro de Investigación Científica de Yucatán, A.C., Unidad de Materiales, Mexico 2 Universidad Autónoma de Yucatán, Facultad de Ingeniería, Mexico 3 Laval University, Dept. of Min-Met-Materials Engineering & CHU de Quebec Research Center, Canada Introduction: Despite the increasing incidence of cardiovascular diseases (CVD), only few biomaterials are commercially available for small diameter vascular grafts (SDVG) (<6 mm)[1]. The dynamic mechanical environment provided by blood vessels creates a complicated sequence of events in which the walls are stretched and the inner lumen is sheared. Changes of mechanical characteristics at the interface between host artery and vascular graft (VG) leads to weakening of the artery wall, loss of endothelial cell (EC) viability, and dilatation of the surgical connection, known as anastomotic aneurysm[2]. Dacron and ePTFE are widely used for big caliber VG but they have unacceptable performance in SDVG[3],[4]. In this regard, segmented polyurethanes (SPUs) are promising candidates not only due to their excellent mechanical properties and good biocompatibility but also given that they can be tailored to specific needs[5]-[7]. Recently, our group demonstrated that the use of SPUs based on amino acid promotes the growth of EC[8]. In this study we analyze the stress distributions existent in the circumferential tensile strength (CTS) and burst strength (BS) tests of SDVG prepared with SPUs based on L-arginine (R) and L-lysine (K). For this, theory of curved beams and pressurized cylinders were applied. Materials and Methods: SPUs were synthesized by the reaction of poly (ε-caprolactone) diol with an excess of 4,4’-methylene-bis-cyclohexyl diisocyanate and then chain extended with either R or K. SDVG were obtained by wrapping a SPUs film around a mandrel, diameter = 5.5 mm. CTS and BS tests were conducted according to ISO 7198 and analysed using the elasticity solutions for curved beam and theory of thick wall cylinders under pressure[9]-[10]. Tecoflex™ was used as reference. Results and Discussions: During CTS test three stresses are generated i.e. circumferential (σϴCTS), radial (σrCTS) and shear (τϴrCTS) as shown in Figures 1a and 1b. At point a and b, τϴrCTS is significant while σϴCTS and σrCTS are negligible. In c and d, τϴrCTS is negligible while σϴCTS and σrCTS are significant, as shown in Figures 1c and 1d. Therefore, CTS test can be considered as an uniaxial pure stress state because σϴCTS is predominant over σrCTS and τϴrCTS. SPUK exhibited lower CTS. During BS test two stresses are generated i.e. tangential (σtBS) and radial (σrBS), Figures 2a and 2b. σtBS is maximum at the inner surface and σrBS is zero at the outer surface. σrBS is maximum at the inner surface and equals the applied pressure (-Pi)[10], Figure 2c. SPUR and SPUK have similar σtBS. Conclusions: SDVG from SPUK and SPUR were tested under CTS and BS and analyzed with elasticity solutions for curved beams and pressurized cylinders. We consider this stress analysis as an innovative contribution for SDVG because ISO 7198 does not include this analysis. O. Castillo-Cruz was awarded of a Government of Canada ELAP Mobility Scholarship; This work was partially funded by CONACYT project No. 220513; NSERC-Canada, CFI-Canada.

Polymer-supported benzimidazolium based ionic liquid: an efficient and reusable Brønsted acid catalyst for Biginelli reaction

A polymer-supported benzimidazolium based ionic liquid (PSBIL) was synthesized by reaction of poly(vinylbenzyl chloride) and benzimidazole followed by ring opening of 1,4-butane sultone and acidification with sulphuric acid.