Showing papers in "Polymer Bulletin in 1999"
TL;DR: In this article, the X-ray diffraction and infrared spectroscopy (IR) analysis confirm that polystyrene macromolecules can be inserted between lamella layers and whose layer separation is consequently higher than in the polymer-free clay.
Abstract: Polystyrene-Na+-montmorillonite(PS-Na+-MMT) nanocomposites are prepared by a simple emulsion polymerization. The X-ray diffraction(XRD) and infrared spectroscopy (IR) analysis confirm that polystyrene(PS) macromolecules can be inserted between lamella layers and whose layer separation is consequently higher than in the polymer-free clay. The enhanced thermal properties of composites are measured by differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA) thermogram and indicate that the glass transition and the decomposition onset temperature of obtained nanocomposites are found to be moved to the higher temperature region. The increased Young's modulus of the obtained nanocomposites is ascribed to the intercalation of PS in clay galleries as well as the fine dispersion of clay particles into the polymer matrix.
301 citations
TL;DR: The aqueous solutions of both forms of purified chitosan were free of aggregation as evaluated by their Huggins constants.
Abstract: The procedures for the purification of commercial chitosan samples as hydrochlorides and in the neutralized form are described. Thermal analysis reveals that, independently of the purification method, all samples are highly pure. The agreement between values of degrees of acetylation determined by conductimetric titrations and by 1H nmr spectroscopy is very good. The aqueous solutions of both forms of purified chitosan were free of aggregation as evaluated by their Huggins constants. The potential use of solutions of chitosan hydrochloride in acid-free aqueous NaCl for the studies aiming to characterize the solution behavior of chitosan is demonstrated.
128 citations
TL;DR: In this article, a kinetic model of hyperbranched polymers by step polyaddition of a BA to a BA monomer including cyclization was developed, and high fractions of cyclics were found in poly[2,2-bis(hydroxymethyl)propanoic acid] (poly (dimethylolpropionic acid)) by mass spectroscopy (ESI/FT MS).
Abstract: A kinetic model of formation of hyperbranched polymers by step polyaddition of a BA
f
monomer including cyclization was developed. Reactions between acyclic-acyclic and acyclic-cyclic molecules and cyclization within acyclic molecules were considered. For cyclization within isomers of an x-mer, a bridging function between linear and spherical structures was used. Fractions of cyclic x-mers are predicted to increase with increasing degree of polymerization x and overall conversion of B groups. High fractions of cyclics were found in poly[2,2-bis(hydroxymethyl)propanoic acid] (poly (dimethylolpropionic acid)) by mass spectroscopy (ESI/FT MS) in a reasonable agreement with the model.
97 citations
TL;DR: In this article, the authors investigated the thermal and mechanical properties of poly(methylmethacrylate-co-dodecylmethACrylate) nanocomposites based upon exfoliated organophilic layered silicates, as a function of the silicate and comonomer content.
Abstract: Thermal and mechanical properties of poly(methylmethacrylate-co-dodecylmethacrylate) nanocomposites based upon exfoliated organophilic layered silicates, were investigated as a function of the silicate and comonomer content. Layered silicates such as sodium bentonite were rendered organophilic by means of ion-exchanging sodium cations for N,N,N,N-dioctadecyl-dimethyl-ammonium cations. Silicate exfoliation was enhanced by means of 5 and 10 wt.-% dodecyl-methacrylate (LMA) addition to afford translucent reinforced acrylic nanocomposites. In contrast to conventional filled acrylic polymers, only 10 wt.-% organophilic silicate was sufficient to increase Young's modulus from 2200 to 4030 MPa, glass temperature from 72 to 80 °C and degradation temperature from 220 to 256 °C with respect to the neat MMA/LMA (90 wt.-%/10 wt.-%) copolymer. Flammability studies, performed on a cone calorimeter, revealed that the maximum heat release rate of MMA/LMA copolymer nanocomposite decreased from 837 kW/m2 to 566 kW/m2. The nanocomposite morphology was examined by means of transmission electron microscopy (TEM).
73 citations
TL;DR: In this paper, a separation between crack initiation and propagation fracture parameters is done by splitting the total energy of the load-displacement curves in two, and the influence of the DDENT specimen height and the test rate on these different parameters is studied, obtaining that varying the height has no influence in the range 40 to 80mm.
Abstract: The fracture properties of an iPP are investigated by the EWF method. A separation between crack initiation and propagation fracture parameters is done by splitting the total energy of the load-displacement curves in two. The influence of the DDENT specimen height and the test rate on these different parameters is studied, obtaining that varying the height has no influence in the range 40 to 80mm, but changing the crosshead speed (2 to 100mm/min) has an effect on the fracture parameters. It is interesting to note that the Initiation Specific Essential Work (W e 1 ) seems not to be sensible to the stress-state transition.
59 citations
TL;DR: The fracture toughness of semi-IPN's of crosslinked epoxy and linear polysulfone (PSf) having morphology spectrum was investigated in this article, where the morphology spectrum is obtained by inserting a PSf film in DGEBA/DDS mixture before cure.
Abstract: The fracture toughness of the semi-IPN's of crosslinked epoxy and linear polysulfone(PSf) having morphology spectrum was investigated. The epoxy resin was based on diglycidyl ether of bisphenol A(DGEBA) and diaminodiphenylsulfone(DDS). The morphology spectrum, which has the gradual change of the morphological feature resulting from the concentration gradient of PSf in the epoxy resin can be obtained by inserting a PSf film in DGEBA/DDS mixture before cure. The relative rate of the dissolution of the PSf in the epoxy oligomer and the rate of curing reaction determine the concentration gradient of the PSf. In the region where the PSf concentration is less then 5%, sea(epoxy)-island(PSf) morphology is observed. As the concentration of PSf increases, the morphology changes to nodular structure, inverted sea-island, and PSf/epoxy homogeneous phase. Up to overall 10wt% of PSf, the fracture toughness of the PSf modified epoxy with morphology spectrum was higher than that of the counterpart with uniform concentration of PSf. These results were ascribed to the plastic deformation of the continuous PSf rich phase which was present in the morphology spectrum.
54 citations
TL;DR: In this article, the synthesis and characterization of ortho-substituted polyanhydrides, poly[1,3-bis(o-carboxyphenoxy)propane anhydride] (o-CPP) and poly[ 1,6-bis (o)-carboxymethylhexane anoxide (p-CPH) was studied.
Abstract: We synthesized polymers that overcome the processing problems associated with aromatic polyanhydrides. In this paper, we focus on the synthesis and characterization of ortho-substituted polyanhydrides, poly[1,3-bis(o-carboxyphenoxy)propane anhydride] (o-CPP) and poly[1,6-bis(o-carboxyphenoxy)hexane anhydride] (p-CPH). By lengthening the alkyl chain between aryl groups (from propane to hexane) and changing the ring substitution pattern from para- to ortho-, we observed enhanced solubility of aromatic polyanhydrides. Ultimately, these polyanhydrides may be useful as polymer scaffolds for use as functional soft tissue substitutes.
51 citations
TL;DR: In this paper, the electric resistance of a composite prepared from these crystalline polymer-grafted carbon black drastically increased to 10 4 -1 times of initial resistance in good solvent vapor of grafted polymer and returned to initial resistance when it was transferred into dry air.
Abstract: Crystalline polymers, such as poly(e-caprolactone) (PCL), poly(ethylene adipate) (PEA), and polyethylene (PE), were successfully grafted onto carbon black surface by direct condensation of terminal groups of these polymers with carboxyl groups on the surface using N,N'-dicyclohexylcarbodiimide as a condensing agent. The electric resistance of a composite prepared from these crystalline polymer-grafted carbon black drastically increased to 10 4 -1 times of initial resistance in good solvent vapor of grafted polymer and returned to initial resistance when it was transferred into dry air. However, the change of electric resistance of the composite hardly observed in poor solvent vapor. These results suggest that these composite can be applied as a novel gas sensor.
46 citations
TL;DR: In this paper, a study on copolymerization of glycolide with lactide and ǫ-caprolactone was performed in the presence of zirconium (IV) acetylacetonate at moderate temperatures (100° and 150°C).
Abstract: A study on the copolymerization of glycolide with lactide and glycolide with ɛ-caprolactone was performed in the presence of zirconium (IV) acetylacetonate at moderate temperatures (100° and 150°C). Zirconium acetylacetonate appeared to be an efficient initiator of copolymerization. The obtained polymers were characterized by high molecular weights. Considerable influence of transesterification on the polymer chain microstructure was found.
45 citations
TL;DR: In this article, a polyelectrolyte complex between chitosan and poly(2-acryloylamido-2-methylpropanesulfonic acid) (PAMPS) was prepared by mixing aqueous solutions of its components or by free radical polymerization on chitosa template.
Abstract: A new polyelectrolyte complex between chitosan and poly(2-acryloylamido-2-methylpropanesulfonic acid) (PAMPS) was prepared by mixing aqueous solutions of its components or by free radical polymerization on chitosan template. The complex formation was sensitive to the ionic strength of the medium. The complex was stable in acidic and neutral medium and dissociated at pH > 8. Its composition did not depend on pH values of the medium and the way of preparation. The mixing dilute aqueous solutions of chitosan and PAMPS resulted in the formation of nanoparticles with mean particle diameter 250 nm and monomodal distribution.
41 citations
TL;DR: Films of aliphatic polycarbonates prepared from epoxides and carbon dioxide were found for the first time to be degradable with a single enzyme, Rhizopus delemar lipase, at 37°C in an acetate buffer solution.
Abstract: Films of aliphatic polycarbonates prepared from epoxides and carbon dioxide were found for the first time to be degradable with a single enzyme, Rhizopus delemar lipase, at 37°C in an acetate buffer solution. In the degradation of polycarbonates containing oxyethylene units, ethylene glycol could be detected in the buffer solution, and was quantified by GLC after conversion to its diacetate. The weight loss values after 168 h were in close agreement with those calculated from the yields of ethylene glycol. Under the same conditions the polycarbonates were degraded much more reluctantly than poly(butylene succinate), an aliphatic polyester. Rhizopus arrhizus lipase was not effective for the degradation of any of these polymers.
TL;DR: In this paper, an efficient synthesis of 4-vinyltriphenylamine has been developed using both anionic and free radical initiators to provide polymers suitable for casting films from solution.
Abstract: An efficient synthesis of 4-vinyltriphenylamine has been developed. This monomer has been polymerised using both anionic and free radical initiators to provide polymers suitable for casting films from solution. Light emitting diodes have been fabricated using this polymer as a hole transport layer (HTL). Comparable devices have been fabricated using evaporated triphenylamine or N,N'-diphenyl-N,N'-ditolylbenzidine as the HTL. Devices with the polymeric HTL display a greater brightness than those with the evaporated layers.
TL;DR: In this paper, a poly(ethylene glycol) macroinitiator prepared by quantitative esterification of MPEG2000 with 2-chloropropionyl chloride was used to perform atom transfer radical polymerization (ATRP) of styrene.
Abstract: Atom transfer radical polymerization (ATRP) of styrene was initiated by a poly(ethylene glycol) macroinitiator prepared by quantitative esterification of MPEG2000 with 2-chloropropionyl chloride. The polymerization carried out at 130°C catalyzed by addition of cuprous chloride and 2,2'-bipyridine has been found to comply to the criteria for a “living” polymerization, since a linear versus monomer conversion plot was found in accordance with the theoretical line indicating essentially 100% initiating efficiency. Also the polymerization is first order with respect to monomer concentration determined in two independent ways. The polydispersity index remained around 1.3 throughout the polymerization and no formation of homopolystyrene could be detected.
TL;DR: A soluble polyphenol was synthesized by oxidative polymerization of bisphenol-A using iron(III)-salen and hydrogen peroxide as catalyst and oxidizing agent, respectively.
Abstract: A soluble polyphenol was synthesized by oxidative polymerization of bisphenol-A using iron(III)-salen and hydrogen peroxide as catalyst and oxidizing agent, respectively The addition of pyridine increased the yield and molecular weight of the polymer NMR and IR analysis showed that the polymer was composed of a mixture of phenylene and oxyphenylene units The iron-salen also induced the polymerization of phenol, m-cresol, and p-t-butylphenol
TL;DR: In this article, a novel approach to branched polyacrylamide was described, which resulted from the amidyl radicals which were formed by the reaction of amide groups with Cu(III) of potassium diperiodatocuprate, K5[Cu(HIO6)2], in alkaline medium and capable of initiating the vinyl polymerization of acrylamides monomer.
Abstract: A novel approach to branched polyacrylamide was described. The branched structure resulted from the amidyl radicals which were formed by the reaction of amide groups with Cu(III) of potassium diperiodatocuprate, K5[Cu(HIO6)2], in alkaline medium and capable of initiating the vinyl polymerization of acrylamide monomer. The obtained polymer was characterized by 1H NMR, FT-IR and intrinsic viscosity measurements.
TL;DR: In this article, room temperature polymerization of three naturally occurring bile acids, cholic, lithocholic and deoxycholic, was carried out using a mixture of diisopropyl carbodiimide (DIPC), and a 1:1 salt of dimethyl amino pyridine and p-toluenesulfonic acid (DMAP/PTSA).
Abstract: Room temperature polymerization of three naturally occurring bile acids, cholic, lithocholic and deoxycholic, was carried out using a mixture of diisopropyl carbodiimide (DIPC), and a 1:1 salt of dimethyl amino pyridine and p-toluenesulfonic acid (DMAP/PTSA). The corresponding polymers were characterized by IR, NMR, Thermal Analysis and X-ray diffraction. Molecular weights were calculated by gel permeation chromatography in the range 50,000–60,000, using polystyrene standards. The polymers were also characterized by mass spectrometry, using matrix assisted laser desorption ionization-time of flight, MALDI-TOF.
TL;DR: Magnesium dichloride supported titanium catalysts were prepared by dissolving anhydrous MgCl 2 in 1-hexanol/isooctane and then recrystallization took place through different techniques such as evaporation of the solvent, quick cooling, precipitation with silicon tetrachloride and precipitation with titanium tetrACHloride.
Abstract: Magnesium dichloride supported titanium catalysts were prepared by dissolving anhydrous MgCl 2 in 1-hexanol/isooctane. Then recrystallization took place through different techniques such as evaporation of the solvent, quick cooling, precipitation with silicon tetrachloride and precipitation with titanium tetrachloride. The FT-IR analysis showed that several degrees of dealcoholation took place as a result of the adducts of MgCl 2 . XROH. Moreover, it was found that the most active catalysts in the polymerization of ethylene were those obtained recrystallizing MgCl 2 by precipitation with SiCl 4 . On the other hand, those directly recrystallized with TiCl 4 were the least reactive and the ones that produced polyethylenes with the highest molecular weights and the lowest degrees of crystallinity.
TL;DR: MALDI-TOF mass spectral analysis was used to characterize the novel unimolecular micelles that result from functionalization of the chain ends of poly(propylene imine) dendrimers with C10 alkanoyl or C12 alkyl groups.
Abstract: MALDI-TOF mass spectral analysis was used to characterize the novel unimolecular micelles that result from functionalization of the chain ends of poly(propylene imine) dendrimers with C 10 alkanoyl or C 12 alkyl groups.
TL;DR: In this article, the authors found that poly(vinyl alcohol), PVA, and poly(acrylic acid), PAA, blends were found to be miscible in the whole composition range as determined by DSC even though some crystallinity remains in blends with PVA concentrations above 50wt%.
Abstract: Poly(vinyl alcohol), PVA, and poly(acrylic acid), PAA, blends were prepared by solution casting. These polymers were found to be miscible in the whole composition range as determined by DSC even though some crystallinity remains in blends with PVA concentrations above 50wt%. Dynamic mechanical measurements of these blends and PAA as a function of temperature show an increase in storage modulus, E', when they reach a temperature of 140°C that is well beyond their softening point. The E' increase in PAA beyond 140°C is attributed to an intramolecular reaction of cyclic anhydride formation that stiffens the chain. Isothermal storage modulus test as a function of time and FTIR measurements at 160°C of PAA and three blends show that this increase in E' is due to cyclic anhydride formation.
TL;DR: In this paper, a poly((3-hydroxypropyl β malate) has been synthesized starting from aspartic acid and benzyloxy-1-propanol as precursors.
Abstract: Poly((3-hydroxypropyl β malate) has been synthesized starting from aspartic acid and benzyloxy-1-propanol as precursors. This new polymer was characterized by 1H and 13C NMR, size exclusion chromatography and differential scanning calorimetry. Homopolymer is soluble in water. Two kinds of amphiphilic copolymers were also prepared and characterized. Such polymers have been synthesized with a view to preparing non-charged degradable associating networks or drug carriers.
TL;DR: In this paper, the authors investigated the polymerization behavior of allytrimethylsilane as a comonomer, and found that it rather acts as a chain transfer agent in the copolymerization, even though considerable amount of allyltrim methylsilane was incorporated in the polymer chain with rac-Et(Ind)2ZrCl2 catalysts.
Abstract: In order to investigate the polymerization behavior of allytrimethylsilane as a comonomer, ethylene was copolymerized with allyltrimethylsilane at 80°C in toluene using methylaluminoxane (MAO) activated metallocene catalysts. The catalytic activity of the polymerization strongly depended on both the type of the catalysts and the concentration of allyltrimethylsilane. End group analysis of the copolymers by means of 1H and 13C NMR spectroscopy revealed that allyltrimethylsilane rather act as a chain transfer agent in the copolymerization, even though considerable amount of allyltrimethylsilane was incorporated in the polymer chain with rac-Et(Ind)2ZrCl2 catalysts. The chain transfer reaction influence strongly the molecular weight and comonomer content of the copolymers.
TL;DR: In this article, the authors studied the porous media flow of solutions of mixtures of poly(ethylene oxide), PEO, and Sodium Dodecyl Sulfate, SDS, and found that the extension thickening of the mixture exhibits a maximum as a function of SDS concentration that mimics the shear viscosity behavior of the polymer-surfactant mixture.
Abstract: In this work, the porous media flow of solutions of mixtures of Poly(ethylene oxide), PEO, and Sodium Dodecyl Sulfate, SDS, was studied. Aqueous solutions of PEO exhibited the well known critical extension thickening effect when flowing through disordered packings of glass spheres. Upon addition of SDS to a solution of fixed PEO concentration, the extension thickening of the mixture exhibits a maximum as a function of SDS concentration that mimics the shear viscosity behavior of the polymer-surfactant mixture. However, when NaCI is added to the mixture, higher extension thickening effects at relatively low SDS concentrations were detected, in spite of the fact that the shear viscosity of the mixtures was about the same as that of equivalent PEO/SDS solutions in deionized water. The results were rationalized in terms of how the formation of SDS micellar aggregates along the PEO chain can alter the ability of the polymer to form transient entanglement networks, which is the cause of the extension thickening behavior.
TL;DR: In this paper, the radical polymerization of styrene was investigated in the presence of diphenyl ditelluride (DPDTe) under varied conditions, and it was shown that the polymer molecular weight increased in proportion to the molar ratio of monomer to initiator suggesting the suppression of bimolecular chain termination reactions.
Abstract: The radical polymerization of styrene was investigated in the presence of diphenyl ditelluride (DPDTe) under varied conditions. In the polymerization without any radical initiator at higher temperature (125°C), the addition of DPDTe surely decreased the polymer molecular weight (M n ) while the polydispersity (M w /M n ) was rather broad. The polymerization with benzoyl peroxide (BPO) as the initiator was also uncontrollable to afford polymers with broad M w /M n probably due to the redox side reaction of BPO with DPDTe. On the contrary, the precision control of M n and the initiating end structure could be achieved by the polymerization with 2,2'-azobisisobutyronitrile (AIBN), that is, M n increased in proportion to the molar ratio of monomer to initiator suggesting the suppression of bimolecular chain termination reactions by the excellent radical capturing ability of DPDTe.
TL;DR: In this paper, a difunctionalized 5,5'-dibromomethylene-2,2' bipyridine ligand was prepared and covalently bound with concurrent crosslinking by a post-polymer modification method to (N-vinylcarbazole-vylalcohol) copolymer.
Abstract: A novel difunctionalized 5,5'-dibromomethylene-2,2' bipyridine ligand was prepared and covalently bound with concurrent crosslinking by a post-polymer modification method to (N-vinylcarbazole-vinylalcohol) copolymer. The electrochemistry and UV-vis spectroscopy results both confirm the covalent attachment of ruthenium transition metal complex to the polymer backbone. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) indicate high thermal stability of the copolymer. The copolymer is also highly phosphorescent making it a potential polymeric material for transition metal based electroluminescent devices.
TL;DR: In this article, Bilayer films composed of a wheat gluten layer and a functionalized polyolefin film were performed by hot press process with the aim of improving the moisture barrier property of hydrophilic gluten films.
Abstract: Bilayer films composed of a wheat gluten layer and a functionalized polyolefin film were performed by hot press process with the aim to improve the moisture barrier property of hydrophilic gluten films. An ethylene/acrylic ester/maleic anhydride terpolymer (Lotader 3410) and an ethylene/glycidyl methacrylate copolymer (Lotader GMA) were used. The use of both Lotader products had no incidence on film opacity, and was effective to reduce dispersion in water and water vapor permeability. In the presence of the terpolymer, the mechanical properties were enhanced and the wide range selectivity of gluten films was preserved.
TL;DR: In this paper, the effects of temperature and draw rate can be unified with a WLF time-temperature shift factor for polyethylene terephthalate diffraction patterns.
Abstract: Synchrotron radiation has been used to record the diffraction patterns from Poly(ethylene terephthalate) for a range of draw rates (0.1 to 10sec−1) and temperatures (90 to 120°C). The patterns were analysed to derive the development of the order parameter and the rates of crystallisation. The effects of temperature and draw rate can be unified with a WLF time-temperature shift factor. Comparison with estimates of chain relaxation processes show that, when the draw rate is faster than the chain retraction process, the onset of crystallisation is delayed until the end of drawing. Crystallisation is very sensitive to both temperature and orientation and has an approximate 4th power dependence on .
TL;DR: In this article, fine emulsion polymerizations of styrene initiated by a redox system ammonium peroxodisulfate/sodium thiosulfite stabilized by a non-ionic emulsifier were kinetically investigated.
Abstract: The fine emulsion polymerizations of styrene initiated by a redox system ammonium peroxodisulfate/sodium thiosulfite stabilized by a non-ionic emulsifier were kinetically investigated. The dependence of the rate of polymerization on conversion or the emulsifier concentration was described by a curve with maximum at medium conversion. The maximum rate of polymerization is proportional to the − 0.45th and 1.5th power of initiator and emulsifier concentration, the number of particles to the 0.32nd and 1.3rd power of initiator and emulsifier concentration and the molecular weight to the − 0.62th and −0.97th power of initiator and emulsifier concentration, respectively. The results show a strong decrease in turbidity at around 20% conversion when emulsion turns into translucent latex. Deviation from the micellar nucleation model was attributed to the solubility of emulsifier in monomer, high level of nonmicellar aggregates, thick interfacial layer and transfer emulsion to microemulsion. The strong decrease of molecular weight with increasing emulsifier concentration is attributed to chain transfer events promoted by the high level of emulsifier at the reaction loci.
TL;DR: In this paper, the essential work of fracture (EWF) fails for the toughness determination of polymers showing a decrease of the specific work, as a function of the specimen ligament, and this type of behaviour was observed for poly(butylene terephthalate) and its core/shell rubber modified blend (PBT/CS).
Abstract: The essential work of fracture (EWF) fails for the toughness determination of polymers showing a decrease of the specific work of fracture, as a function of the specimen ligament. This type of behaviour was observed for poly(butylene terephthalate) (PBT) and its core/shell rubber modified blend (PBT/CS). It was found that this peculiar behaviour is due to a ductile-to-brittle transition (DBT) in the crack propagation phase. Experimental data were corrected by considering only the ductile-fractured specimen area. When a non linear function of the type y=a+bx−1 was applied for the corrected specific work of fracture and ligament data, the specific essential work of fracture (we) could be deduced. The latter being an inherent material toughness parameter was compared with the critical J-integral (Jc) values and a good correlation was found between them.
TL;DR: In this article, a variety of transition metal catalysts were used for the polymerization of phenylacetylenes containing imino groups, and the produced polymers were orange to red solids and soluble in common organic solvents except for poly(1).
Abstract: Polymerization of phenylacetylenes containing imino groups with a variety of transition metal catalysts was investigated. The monomers employed were N-(4-ethynylbenzylidene)aniline (1), N-(3-ethynylbenzylidene)aniline (2), N-(4-ethynylbenzylidene)-2,6-diisopropylaniline (3), N-(4-ethynylbenzylidene)-4-hexylaniline (4), N-(4-ethynylbenzylidene)butylamine (5), and N-(4-ethynylbenzylidene)octylamine (6). All of the monomers smoothly polymerized with [(nbd)RhCl]2-Et3N to give polymers in excellent yields, whereas no polymerization took place with W, Mo, and Fe catalysts. The produced polymers were orange to red solids and soluble in common organic solvents except for poly(1). UV-vis spectra of the polymers indicated that the main chains possess a similar degree of conjugation to that of poly(phenylacetylene). However, the stability of polymer backbone toward oxidative cleavage in solution remarkably improved, which is contributed by the electron-withdrawing character of imino groups.
TL;DR: In this paper, the reaction behavior of resins based on 4-vinylpyridine and N,N′-dimethylacrylamide and 2-acrylanidoglycolic acid as comonomers, compared with the crosslinked homopolymers, towards Hg(II, Cd(II), Zn, Pb, and Cr(III) was studied at different pHs depending on the metal ion.
Abstract: Sorption behavior of resins based on 4-vinylpyridine and N,N′-dimethylacrylamide and 2-acrylamidoglycolic acid as comonomers, compared with the crosslinked homopolymers, towards Hg(II), Cd(II), Zn(II), Pb(II), and Cr(III) was studied at different pHs depending on the metal ion. Some resins show that from pH = 1.0 or 2.0 Hg(II), Cr(III), and Cd(II) were sorbed significatively from an aqueous solution of 1.0 g/L. Hg(II) and Cr(III) were eluted significatively in acidic media.