Polymer materials based on ethylene copolymers with substituted norbornene

The copolymers of ethylene with 5-ethylidene-2-norbornene containing 10–65% of the cyclic comonomer have been prepared with the use of three ansa-metallocene catalysts, namely, Et[Ind]₂ZrCl₂-methylaluminoxane, Et[IndH₄]₂ZrCl₂-methylaluminoxane, and Me₂Si[Ind]₂ZrCl₂-methylaluminoxane. Side groups >C=CH-CH₃ capable of participation in the ozonolysis reaction have been incorporated into polymer chains via the copolymerization of ethylene with the cyclic comonomer. As evidenced by DSC, and X-ray diffraction, and very cold neutron scattering measurements of the supramolecular structure of the copolymers, the enrichment of the copolymer with the cyclic comonomer causes transformation of the ethylene-5-ethylidene-2-norbornene copolymer from the semicrystalline state to the amorphous state. This effect is accompanied by an increase in the density and optical transparency of the material and a rise in its glass transition temperature. Among the copolymers under study, the highest T _g (83°C) is exhibited by the copolymer synthesized with the Et[Ind]₂ZrCl₂-methylaluminoxane catalyst and containing 30 mol % 5-ethylidene-2-norbornene.     

Novel ethylene/norbornene copolymers as nonreleasing antioxidants for food‐contact polyolefinic materials

An efficient procedure for the copolymerization of ethylene (E) with a novel norbornenic comonomer (N_ArOH) bearing a stabilizing moiety analogous to commercial antioxidant 2,6‐di‐tert‐butyl‐4‐methylphenol (BHT) is successfully developed. This study is aimed at: i) tuning the concentration of the stabilizing function along the polymer chain, and ii) preparing “nonreleasing” polymeric additives specifically destined to protect commercial low‐density polyethylene (LDPE). Films obtained from blends of the novel E/N_ArOH copolymers with an antioxidant‐free LDPE matrix are characterized by superior thermal, thermo‐oxidative, and photostability when compared not only with neat LDPE films but also with films stabilized by the commercial BHT additive. Specific migration tests conducted in order to investigate the nonreleasing character of the novel macromolecular additives confirm the reduced risk of migration, from the films into food simulants, of unreacted comonomer or degradation products bearing the antioxidant moiety. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013 , 51, 1007–1016     

Synthesis and luminescent properties of new europium-containing copolymers based on norbornene functional derivatives

New copolymers containing oxadiazole, carbazole, and europium-containing fragments in the side chains were synthesized by ring-opening metathesis polymerization. The polymeric materials obtained were characterized by IR spectroscopy, GPC and DSC methods, and elemental analysis. All the copolymers possess strong metal-centered photoluminescence in solution and in thin film. In the electroluminescence spectra, the emission of the europium cations is exhibited and a broad band with the maximum at 507 nm is observed, which supposedly is attributable to the emission of the electroplexes between the polymeric matrix and the europium-containing fragments.     

Nickel catalysts for the addition polymerization of norbornene and its derivatives and for their copolymerization with ethylene

The addition polymerization of norbornene and its derivatives has been carried out in the presence of a nickel complex or carboxylate and an electron acceptor to obtain amorphous polymers with bicyclic units. Norbornene copolymers with conjugated dienes or ethylene cannot be obtained with these catalysts because of rapid chain transfer reactions. Norbornene can be copolymerized with ethylene under mild conditions in the presence of nickel phosphorylide chelates without using any cocatalyst. In most cases, the backbone of the resulting copolymer consists of alternating comonomer units. The new catalysts allow ethylene to be copolymerized with norbornene derivatives containing ester substituents.     

Terbium-containing copolymers based on the norbornene functional derivatives. Synthesis, photoluminescent and electroluminescent properties

New carbazole- and terpyridine- containing norbornene derivatives were synthesized and structurally characterized. On the basis of these compounds by the method of metathesis polymerization copolymers were obtained with carbazole and terpyridine fragments in side chains. The synthesized copolymers react with terbium pyrazolonate complex to form the terbium-containing polymeric materials exhibiting the metalcentered photo- and electroluminescence.     

Alternating copolymers of propylene and alkyl acrylates

High-molecular-weight alternating and acrylate-rich copolymers of propylene and ethyl acrylate were prepared by using boron trifluoride to complex the acrylate ester. The polymerizations were run at room temperature and autogeneous pressures with free-radical initiation. The polymers were characterized by their nuclear magnetic resonance (NMR) and infrared (IR) spectra, differential scanning calorimetry, and gel permeation chromatography. The proton and ¹³C NMR spectra show that the equimolar copolymers are alternating to a high degree.     

Atom transfer radical polymerization of (meth)acrylates and their novel block copolymers with vinyl acetate

Homopolymerization of methyl acrylate (MA) and methyl methacrylate (MMA) by atom transfer radical polymerization (ATRP) were carried out at 90 °C using methyl-2-bromopropionate (MBP) as initiator, copper halide (CuX, X=Cl, Br) as catalyst, 2,2^′-bipyridine (bpy) or N,N,N^′,N^′,N^″-pentamethyldiethylenetriamine (PMDETA) as ligand in 1-butanol (less polar and containing OH) and acetonitrile (more polar) solvents. It was found that with CuCl/bpy catalyst ATRP of MA and MMA in 1-butanol proceeded faster than that in acetonitrile. The rate of ATRP of MA and MMA in acetonitrile and 1-butanol was comparable when CuCl/PMDETA used as catalyst system. The number-average molecular weights increased with conversion and polydispersities were low . The ATRP of MA and MMA with vinyl acetate telomer having trichloromethyl end group (PVAc-CCl₃) were also used to synthesize new block copolymers. The structures and molecular weight of synthesized PVAc-b-PMA and PVAc-b-PMMA were characterized by ¹H NMR, FTIR spectroscopy and gel permeation chromatography (GPC) and shown that the block copolymers were novel.     

Bimetal cobalt-zinc MOF and its derivatives as anode materials for lithium-ion batteries

Journal of Solid State Electrochemistry - The purplish-red rod-like crystal structure of novel bimetallic metal–organic-frameworks (MOF) {CoZn[(4,4′-BDA)(Phen)]2}n has been obtained by...     

Thermal studies of copolymers of acrylonitrile with haloalkyl acrylates and methacrylates

Thermal behaviour of copolymers of acrylonitrile containing 2–15 mol% of halogen substituted alkyl acrylates and methacrylates was studied by differential scanning calorimetry and thermogravimetry (TG) under nitrogen atmosphere. It was observed that incorporation of haloalkyl acrylates or methacrylates in polyacrylonitrile decreases the second order transition and does not affect the extent of nitrile oligomerization but the oligomerization is delayed. TG analysis of the copolymers revealed that the threshold decomposition temperatures of these copolymers are ≥260° as compared to 248° for pure polyacrylonitrile. The residue at 850° was less for the copolymers and it further decreases with increase in the comonomer concentration.     

Ene-yne-ene and ene-yne-yne metathesis of norbornene derivatives

Norbornene derivatives 4 and 5 containing sidechains bearing an internal alkyne and either a terminal alkene or a terminal alkyne were found to undergo a cascade of metathesis reactions when treated with ruthenium based metathesis catalysts to form highly functionalised pentacyclic products. The reactions illustrate an interesting difference in reactivity between Grubbs’ catalyst and the second generation catalyst, with the former being more reactive for the early steps of the cascade.     

Copolymerization of cyclopropyl-substituted dioxolanylmethyl acrylates with styrene and synthesis of photosensitive copolymers

Radical copolymerization of new monomers, cyclopropyl-substituted dioxolanylmethyl acrylates, with styrene in benzene solution was studied at low conversions. The copolymer compositions and the relative activity constants and Alfrey-Price constants of cyclopropane-containing dioxolanylmethyl acrylates were determined. The sensitivity of the copolymers obtained to UV radiation was studied, and the possibility of using them as photoresists was revealed.     

Graft and block copolymers of cellulose and its derivatives

Ohne Zusammenfassung

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Graft and block copolymers of cellulose and its derivatives

     

Binary and ternary complexes of inosine

Formation of binary and ternary complexes of Cu(II) and Ni(II) metal ions with inosine as a primary ligand and some biologically important aliphatic and aromatic carboxylic acids (succinic, oxalic, malic, maleic, malonic, tartaric, 5-sulfosalicylic, salicylic and phthalic acids) as secondary ligands was studied by the potentiometric technique at 25 degrees C and 0.10 M (NaNO(3)) ionic strength. The ternary complex formation was found to take place in a stepwise manner. The stability constants of these binary and ternary systems were calculated. The lower stability of 1:2 complexes of inosine compared to the corresponding 1:1 systems is in accord with statistical considerations. The values of Delta log K for the ternary complexes studied have been evaluated and discussed. The mode of chelation of ternary complexes was ascertained by conductivity measurements.     

Binary and ternary complexes of sulphamethoxazole

Summary The complex formation equilibria involved in the binary and ternary systemsM(II)-sulpha andM(II)-phen-sulpha were investigated by potentiometric titrations at 25°C and a ionic strength of 0.1N NaNO₃ (M = Cu, Ni, Co, Zn;sulpha = sulphamethoxazole;phen = phenanthroline). The stability constants of the binary and ternary complexes follow the order ofIrving andWilliam. The formation of the ternary complex is discussed in terms of the binary species. The mode of chelation was ascertained by conductivity measurements.

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Binäre und ternäre Komplexe von Sulphamethoxazol

Zusammenfassung Die an den binären und ternären SystemenM(II)-sulpha undM(II)-phen-sulpha (M = Cu, Ni, Co, Zn;sulpha = Sulphamethoxazol;phen = Phenanthrolin) beteiligten Komplexbildungsgleichgewichte wurden bei 25°C und einer Ionenstärke von 0.1N NaNO₃ mittels potentiometrischer Titration untersucht. Die Stabilitätskonstanten der binären und ternären Komplexe gehorchen der Reihenfolge vonIrving undWilliam. Die Bildung der ternären Komplexe wird auf der Basis der binären Spezies diskutiert. Die Art der Chelatbildung wurde durch Leitfähigkeitsmessungen ermittelt.

     

Thermal behaviour of copolymers of acrylonitrile with haloalkyl acrylates or methacrylates

Thermal stabilities of copolymers of acrylonitrile with 4–14 mol% of 3-chloro-2-hydroxypropyl acrylate or methacrylate, 2-chloroethyl acrylate or methacrylate and 2-bromoethyl acrylate or methacrylate were studied by TGA in air. A two-step degradation between 300 and 350° and 600 and 650° is observed for both PAN and the copolymers. Initially, the degradation is slow up to 350° for the copolymers (8–23% wt loss) compared with PAN (27% wt loss); the trend reverses after 350°. A mechanism of the degradation has been proposed on the basis of i.r. studies of the residue of the copolymers isothermally heated at 300° for 10 min. The influence of the haloalkyl comonomers on the flammability of acrylic copolymers in terms of limiting oxygen index is also reported.     

The reaction pattern of norbornene with excited state carbonyl compounds: Photochemical preparations of norbornene derivatives

We established that acetylacetone and acetone photolytically sensitize norbornene to undergo an efficient radical addition of solvent (ranging from hexane, cyclic ethers, haloalkanes, acetone, alcohols and acetonitrile) across the double bond. In view of its synthetic applicability, sensitized photoreactions of norbornene were reviewed and their mechanisms were compared. Photolysis of acetylacetone in the presence of norbornene in hexane induced i) acetylacetone to cycloadd to norbornene giving the expected 1,5-diketone, and ii) sensitization by triplet excited acetylacetone to generate reactive norbornene, which underwent dimerization as well as the addition of a solvent molecule by radical chain processes. In other solvents, the radical chain addition of solvent dominated the photoreaction, and superseded the cycloaddition, to give excellent to good yields of adducts to norbornene. While the excited species of acetylacetone for the sensitization was deduced to be its spectroscopic triplet excited state, that for the cycloaddition should involve a different one which may be a twisted triplet acetylacetone; sensitization experiments showed that the cycloaddition did not occur from the spectroscopic triplet state. Triplet excited acetone sensitized norbornene to undergo the same solvent addition more efficiently and cleanly than acetylacetone did. In view of various conflicts existing in the proposed energy transfer mechanism, the sensitized norbornene reactions were rationalized with electron transfer and a cation radical chain mechanism.     

Near-infrared analysis of the styrene content of copolymers with aliphatic acrylates and methacrylates

Abstract

The styrene content of copolymers with aliphatic acrylates and methacrylates is determined by near-infrared absorption measurements in chloroform at 2.144μ. The plot of absorbance vs. concentration is linear over the range 0 to 82.1 g./1.     

Synthesis of a novel polyester-ether copolymer and its derivatives as antistatic additives for thermoplastic films

Development of antistatic thermoplastic elastomer composites is gaining much interest in scientific and industrial aspects. In this contribution, a novel type of polyester-block-ether copolymer (PEBE), PEBE with ionic liquid (PEBE-IL) and quaternized PEBE (PEBE-Q) were synthesized, characterized and compounded with a commercial bottle grade polyester (PET) resin. It was found that the surface resistivity of the PET composite films was around 10⁹–10¹⁰ Ω/sq. The addition of the PEBE copolymers as an antistatic agent into PET matrix resulted in almost 10⁶ times enhancement in surface resistivity compared to neat PET film. Among the PET films with an antistatic agent, it was emphasized that PEBE-IL and ionic liquid doping to PET matrix led to a relatively lower crystallization degree, surface resistivity, contact angle and breaking force with a translucent appearance compared to neat PET film. Furthermore, it was illustrated that antistatic PET films with fine-tune physical, mechanical and morphological properties can be achieved by choosing appropriate antistatic agent type and amount.