Functional polyamides. 3. Synthesis and chelating properties of a new poly(amide thioether)

Polymerization of β,β′-(ethylenedithio)dipropionitrile

1 IUPAC name: 4,7-dithiadecane dinitrile.

with formaldehyde in the presence of sulfuric acid was carried out in order to permit the synthesis of polymides containing thioether groups. The obtained poly(amide thioether)s were characterized; they coordinate mercury (II) with a high degree of selectivity.     

Thermal analysis of poly(phenylene sulfide) polymers. I: Thermal characterization of PPS polymers of different molecular weights

Thermal properties of Fortron®

1 ®Registered trademark of Hoechst Celanese Corporation.

poly(phenylene sulfide) (PPS) polymers of different molecular weights were studied by DSC. Crystallization studies revealed that the ability of these polymers to crystallize decreases with increasing molecular weight. The Avrami equation poorly describes the isothermal crystallization of PPS. Lamellar crystallization was observed for the lowest molecular weight sample. For the other, higher molecular weight polymers the Avrami exponent is always between 2 and 3, suggesting development of distorted spherulites with heterogeneous nucleation. The temperature dependence of the solid and melt heat capacities have been determined. The solid specific heat capacity did not exhibit a molecular weight dependence. The heat capacity increase at the glass transition, T_g, has been calculated to be 28.1 J°C^?1 mole^?1. The equilibrium melting point of PPS has been estimated to be 348.5°C using the Hoffman–Weeks method. The T_g of PPS increases with molecular weight. The T_g of the highest molecular weight evaluated is 92.5°C. A DMA relaxation peak corresponding to the onset of the phenylene ring rotation occurs at ?92°C. Only the highest molecular weight could be quenched to a completely amorphous state.     

Separation of heavy metal ions by complexation on poly (N-vinyl imidazole) hydrogels

Summary Poly (N-vinyl imidazole) (PVIm) hydrogels were prepared by -irradiating binary mixtures of N-vinyl imidazole-water in a ⁶⁰Co- source having 4.5 kGy/h dose rate. These hydrogels were characterized with gravimetric and spectrophotometric studies. Hydrogels with equilibrium swelling ratio of 600% in distilled water were used in the metal ion adsorption studies. The effects of pH, equilibration time, and initial metal ion concentration were considered in batch equilibrium study on the chelation of Cu²⁺, Co²⁺, Cd²⁺, and Pb²⁺ ions. Maximum metal ion adsorption were observed at pH=6.0. It has also been observed that the amount of adsorbed metal ions decreased at lower pHs because of protonation of PVIm ring.     

Glass fiber-reinforced epoxy composites

Glass fiber-reinforced epoxy composites were prepared from the matrix resins tetraglycidyl diaminodiphenylmethane

1 Systematic name: N,N,N′,N′-Tetrakis(2,3-epoxypropyl)-4,4′-diaminodiphenylmethane.

(TGDDM) and tetraglycidyl bis(o-toluidino)-methane

2 Systematic name: N,N,N′,N′-Tetrakis(2,3-epoxypropyl)-4,4′-bis(o-toluidino)methane.

(TGMBT) using various amines like 4,4′-diaminodiphenylmethane (DDM), 4,4′-diaminodiphenylsulfone (DDS) and diethylene triamine (DETA) as curing agents. The fabricated laminates were evaluated for their mechanical and dielectrical properties and chemical resistance. The composites prepared using an epoxy fortifier (20 phr) showed significant improvement in the mechanical properties.     

Antioxidants and stabilizers, 107. Reaction of N-phenyl-1,4-benzoquinoneimine with the 1-cyano-1-methylethyl-radical

The reaction of N-phenyl-1,4-benzoquinoneimine (I)

1 Decoding of abbreviations see p. 103/104.

and 4-hydroxydiphenylamine (II) with the carbon centred 1-cyano-1-methylethyl radical (R^·) was studied in connection with an investigation of the action mechanism of industrial antidegradants, such as N-phenyl-N′-sec-alkyl-1,4-phenylenediamines. The mixture of I and II reacts very readily with R^·, giving rise to III , VI , and VIII . I alone reacts much slowlier, and the reaction mixture contains more products. IV and VII were identified along with III . Under the conditions used, II alone does not react at all. IV exists in two isomeric forms, syn and anti. VIII is very labile; XI was isolated from its transformation products. Reduction of IV gives V , which is labile, similarly to VIII .     

Temperature dependent dc dark conductivity in poly(n-vinyl carbazole): Arrhenius and density of state model

DC dark conductivity (σ) has been measured in thin films of poly(N-vinyl carbazole) (PVK). The dependence of σ on temperature (T) followed a typical Arrhenius relation but at the same time a relation σ(T)α exp(-[T₀/T]²) could be fitted to the experimental points. To reconcile this observation, it is suggested that the expression for the conductivity then is expected to contain in addition to the activation term, the factor exp[-(T₀/T)²] which is the behavior expected in a trap-free molecular hopping system with a Gaussian distribution of sites energy, so that the DC dark conductivity would be of the functional form .     

Skin and layer formation in films prepared from carbohydrates,poly(ethylene-co-acrylic acid), and polyethylene

Cornstarch, a canary dextrin, and a maltodextrin were compared in films blown from carbohydrates compounded with poly(ethylene-co-acrylic acid) (EAA), low-density polyethylene (LDPE), and aqueous ammonium hydroxide plasticizer. Dextrins or maltodextrins having dextrose equivalent values of one and greater caused dark-colored films with caramel odors, probably due to Maillard reactions. Blown films with hydrophobic skins and water sensitive cores were produced with the dextrinized carbohydrates, but not from natural cornstarch. Water sensitivity of films containing the dextrinized carbohydrate was reduced by recycling the films through the blown film die. A mechanism for development of the skins is proposed, as is a method for preparing thin semipermeable membranes. © 1993 John Wiley & Sons, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Stevensanaloge,Durch Nickelkomplexe Katalysierte Umlagerung Von Triarylphosphoryliden Und Darstellung Sowie Strukturbestimmung Von Phosphorylid-Nickeltricarbonylkomplexen

The Stevens rearrangement of the triarylphosphorusylids R₃ P=CHR′ (III) (R′ = H, CH₃, C₂ H₅) to diarylbenzylphosphines (V) is catalyzed by nickel complexes (e.g., (COD)₂ Ni (I)). Attempts to prepare trimesitylphosphine-methylene result in direct formation of dimesityl (mesitylmethyl) phosphine (XII) — the first recorded direct Stevens rearrangement of a phosphorusylid. Phosphorusylids react with nickeltetracarbonyl without rearrangement to give complexes of the type R₃P=CH_a · Ni(CO)₃ (XIV). The structure of XIV has been established by the IR and NMR spectra and confirmed by an X-ray structural determination.

1 B. L. Barnett and C. Krüger, J. Cryst. Mol. Struct., im Druck.

The ylid is bonded to the nickel through the C-atom with resulting hybridization from sp² towards sp³.     

Thermomechanical properties of blends of pectin and poly(vinyl alcohol)

Blends of citrus pectin and several types of poly(vinyl alcohol) were investigated to determine the effects of compositional variables and polymer type on film properties. Some films were also plasticized with glycerol. Films were cast from water onto Lexan™ plates, dried, and removed. Thermomechanical properties were obtained using a dynamic mechanical analyzer, and thermodynamic transitions were also obtained using a differential scanning calorimeter. Increasing the amount of poly(vinyl alcohol) in the blends reduced the storage and loss modulus of the films above the glass transition temperature (T_g). The T_g values observed decreased as the amount of PVOH in the blend increased. Addition of glycerol depressed the PVOH T_g and merged it into the T_g of the pectin/glycerol blend. Changes in the molecular weight and degree of ester hydrolysis of poly(vinyl alcohol) exerted a rather small effect on the blends. © 1996 John Wiley & Sons, Inc.

1 Reference to a brand or firm name does not constitute an endorsement by the U.S. Department of Agriculture over others of a similar nature.

     

Miscibility of linear low density polyethylene (LLDPE)-graft-poly(methyl methacrylate) with poly(vinylidene fluoride) (PVF2) and its application as compatibilizer LLDPE/PVF2 blends

Differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used to study the miscibility of blends of a graft copolymer of poly(methyl methacrylate) on linear low density polyethylene (LLDPE-g-PMMA, G-3) with poly(vinylidene fluoride)

1 Systematic name: poly(1,1-difluoroethylene).

(PVF₂) and the compatibilization of blends of LLDPE/PVF₂. The specific interaction between PMMA side chains and PVF₂ in G-3/PVF₂ binary blends is weaker than that between the homopolymers PMMA and PVF₂. There are two states of PVF₂ in the melt of a G-3/PVF₂ (60/40, w/w) blend, one as pure PVF₂ and the other interacting with PMMA side chains. The miscibility between PMMA side chains and PVF₂ affects the crystallization of PVF₂. LLDPE-g-PMMA was demonstrated to be a good compatibilizer in LLDPE/PVF₂ blends, improving the interfacial adhesion and dispersion in the latter. Diffusion of PMMA side chains into PVF₂ in the interfacial region reduces the crystallization rate and lowers the melting point (T_m) and the crystallization temperature (T_c) of PVF₂ in the blends.     

Fracture behavior of coated/uncoated graphite-epoxy composites

The static delamination behavior of graphite/epoxy composite specimens subjected to mode I tensile opening (using UDCB

1 Uniform double cantilever beam.

specimens), and pure mode II shear loading (using ENF

2 End-notched flexural.

specimens) were studied. The graphite epoxy composites for the study were made from commercially treated fibers, with and without an electropolymerized interlayer. The mode I fracture energy (G_IC) was found to be significantly higher (more than 50 percent) for the coated fibers. However, this improvement was accompanied by a high reduction (more than 3 times) in the mode II fracture energy (G_IIC). This effect is apparently related to poor adhesion between the interlayer and the epoxy resin, which may be corrected by use of a “top layer” of appropriate composition to form chemical bonds between the phases. The fracture toughness (K_IC) of composites made with commercially treated fibers was also evaluated, using double side-notched specimens.     

A polymeric amine–copper(II) complex as catalyst for the hydrolysis of 1,2,2-trimethylpropyl methylphosphonofluoridate (soman) and bis (1-methylethyl) phosphorofluoridate (DFP)

The Cu (II) complex of poly-4-vinylpyridine, quaternized with 19 mol % ethyl bromide and 36 mol % 4-chloromethyl-4′-methyl-2,2′-bipyridine, was examined as a catalyst for the hydrolysis of the toxic organophosphorous compounds bis (1-methylethyl) phosphorofluoridate ( 1 ,

1 Registry no.: 1 , 55-91-4; 2 , 96-64-0.

DFP) and 1,2,2-trimethylpropyl methylphosphonofluoridate ( 2 , soman). Studies were carried out at 25.0 and 37.0°C for both substrates in MOPS buffer at pH 7.0. In the presence of 7.31 × 10^?3 M catalyst at 25.0°C, soman is hydrolyzed with a first-order rate constant of 0.019 min^?1 (t_1/2 = 37.5 min), whereas DFP hydrolyzes with a rate constant of 0.011 min^?1 (t_1/2 = 63.8 min). For soman, this represents a 14-fold increase over the uncatalyzed rate in the same buffer. Other studies examined the effect of a strongly sorptive polymeric resin on catalysis by this copper-containing polymer and found a dramatic decrease in the hydrolysis rate of soman in the presence of the polymeric sorbent.     

Effects of water content on the properties of starch/poly(ethylene–vinyl alcohol) blends

The physical properties of unmodified starch, poly(ethylene vinyl alcohol), glycerol, and water mixtures are reported. Thermal and melt-flow properties of the preprocessed, physically mixed materials were determined along with the tensile properties and morphology of injection-molded microtensile samples. Melt-flow properties were measured by a capillary rheometer, and the water content was varied from 4 to 18%. The morphology, rheology, and tensile properties are all highly related to the percentage of water present. A transition in the tensile properties and morphology of the blends was observed at approximately 11% moisture content. © 1994 John Wiley & Sons, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Simultaneous fluorine elimination and alkylation of poly(tetrafluoroethylene)

PTFE (powder or foils) was defluorinated and derivatized in a one-step process by alkyl- and aryllithium in the presence of tetramethylethylenediamine

1 Systematic name: 1,2-Bis-[dimethylamino]ethane.

(TMEDA) as a catalyst. As evidenced by infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and elemental analysis the C₄H₉-, C₈H₁₇-, C₁₂H₂₅- or phenyl groups were attached to a partly defluorinated macromolecular chain. Analogous reactions with dilithioaryl or dilithioalkyl agents presumably lead to crosslinking of the polymeric chains through alkyl or aryl groups. When the PTFE powder is treated with more concentrated RLi (>3 mol L^?1) at temperatures >150°C, the defluorination is almost quantitative even in the absence of the catalyst. The TMEDA-catalyzed reaction proceeds via elimination and nucleophilic addition. On the other hand, more concentrated RLi in the absence of the catalyst seems to react via a radical mechanism.     

The STOBBE Condensation with Pyrrolyl Aldehydes – a synthesis of indole derivatives

The condensation of pyrrolyl-2-aldehyde or 1-methyl-pyrrolyl-2-aldehyde with dimethyl succinate, using sodium hydride as condensing agent, gave predominantly the halfesters 1a and 1c respectively. Their structure and (E)-configuration

1 i. e., pyrrol ring and COOCH₃ group are in trans position. This nomenclature follows the IUPAC 1968 Tentative Rules, Section E, Fundamental Stereochemistry, J. org. Chemistry 35 , 2849 (1970).

were confirmed by their cyclisation to the corresponding indole derivatives 2a–h .     

Photochemical and thermal stability of amaranth (FD&C red no. 2) in aqueous media

The decomposition of the formerly

1 This dye was delisted by the U. S. Food and Drug Administration in 1976, and has not been legally used in the U. S. in foods, drugs, or cosmetics since that date.

used food and pharmaceutical dye amaranth (FD&C Red No. 2) in water was studied under a variety of conditions. A matter of some concern is that one of the decomposition products is α-naphthylamine, a known carcinogen.     

Copolymerization of N-vinyl phthalamide with acrylate and methacrylate monomers and preliminary analysis of the stereochemistry of poly(N-vinyl phthalamide)

Summary N-Vinyl phthalamide was copolymerized with methyl methacrylate, isobutyl methacrylate or butyl acrylate. The copolymerizations were initiated free radically and it was necessary to conduct the polymerizations in solution or else insoluble products would result. In most cases the polymerizations preceded to relatively high conversions in a short time. The conversions necessitated the use of high conversion methods to calculate the reactivity ratios. The N-vinyl phthalamide was found to be the less reactive monomer in all cases. As part of this study, poly(N-vinyl phthalamide) homopolymer was synthesized by free radical initiation. While the ¹H-NMR spectrum yield very little information concerning polymer stereochemistry, the methine carbon resonance in the ¹³C-NMR spectrum displayed a sensitivity to polymer stereochemistry.     

Porous bead aliphatic-aromatic methacrylate copolymers,I. Effect of polymerization conditions on porous structure formation of methyl methacrylate — di(methacryloyloxymethyl)naphthalene copolymers

The influence of inert porogenic mixture and monomer mixture composition and concentration on specific surface areas, pore size distribution, volumes of pores capable of capillary condensation of nitrogen and true density of copolymers were investigated for a new type of methacrylate monomer system: methyl methacrylate and di(methacryloyloxymethyl)naphthalene. The obtained copolymers exhibit similar character as it is typical for PPS

1 PPS = Porous by Precipitant and Solvent.

styrene-divinylbenzene resins.     

Detection of Radicals at the Photolysis of tert-Butyl Hydroperoxide in DMSO and water

The decomposition of tert-butyl hydroperoxide by photochemically induced reactions in DMSO

1 Abbreviations used: DMSO, dimethyl sulfoxide; DMSO-d₆, completely deuterium labelled dimethyl sulfoxide; cw-ESR, continuous-wave Electron Spin Resonance; u. v., ultra violet; DMPO, 5, 5-dimethyl-I-pyrroline N-oxide; TMPO, 3, 3, 5, 5-tetramethyl-l-pyrroline N-oxide.

and water was investigated by cw-e.s.r. spectroscopy. The products tert-butylperoxyl, methyl and sulfur-centered free radicals were identified. The tert-butoxyl free radical is involved in the primary process as shown by time-resolved e.s.r. technique. On the basis of directly identified radical species, a mechanism for the photochemically induced reactions of tert-butyl hydroperoxide in DMSO is proposed. At concentrations below 0.8 mol · l⁻¹ the radical formation from tert-butyl hydroperoxide proceeds by cleavage of the O O bond rather than by hydrogen abstraction.     

Synthesis,characterization and corrosion protection properties of poly(N-vinyl carbazole-co-glycidyl methacrylate) coatings on low nickel stainless steel

Methacrylate based copolymers are considered as one of the best organic coating materials for anticorrosive application. Poly(N-vinyl carbazole-co-glycidyl methacrylate) have been synthesized by free radical solution polymerization technique from different mole ratios of N-vinyl carbazole (N-Vc) and glycidyl methacrylate (GMA) and characterized using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (¹H NMR and ¹³C NMR). Thermal analyses of the poly(N-Vc-co-GMA) were performed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The number average molecular weight (M_n) of different compositions of the same was determined by gel permeation chromatography (GPC). The corrosion performances of low nickel stainless steel specimens coated with different composition of copolymers were investigated in 1 M H₂SO₄ using potentiodynamic polarization, electrochemical impedance spectroscopic (EIS) method, scanning electron microscopic (SEM) and energy dispersive X-ray analysis (EDAX). Poly(N-Vc-co-GMA) have been provided in order to achieve adherent, low permeability to aggressive ions as well as environmentally favored good anticorrosive coating. Electrochemical corrosion test and surface analysis results clearly showed that poly(N-Vc-co-GMA) coatings served as a stable host matrix on low nickel stainless steel against corrosion. It was also observed that the coatings of poly(N-Vc-co-GMA) with equal mole ratio of N-Vc and GMA exhibited the best corrosion resistance among all combinations.