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  • Chemistry  (9,981)
  • 1995-1999  (1,469)
  • 1985-1989  (8,512)
  • 1980-1984
  • 1999  (1,469)
  • 1988  (8,512)
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  • 1995-1999  (1,469)
  • 1985-1989  (8,512)
  • 1980-1984
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  • 1
    ISSN: 1432-0975
    Keywords: Key words Otolith ; Chemistry ; ICP-MS ; Stock discrimination ; Epinephelus striatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract  We examined the utility of otolith minor and trace element chemistry, assayed with inductively coupled plasma mass spectrometry (ICP-MS), as a means of delineating population structure in the Nassau grouper (Epinephelus striatus). We characterized the elemental composition of otoliths collected in 1993 from three locations in Exuma Sound, Bahamas and from Glover Reef, Belize in 1995. A single location in Exuma Sound was sampled in 1994 to test temporal variability in otolith composition. Five elements (Ca, Zn, Sr, Ba and Pb) were routinely detected, at levels significantly above background, by solution-based ICP-MS. Results from analysis of variance of elemental data, expressed as a ratio to Ca, indicated that there were no significant differences among the Exuma locations for any element, but significant variability was found between Glover Reef and the pooled Exuma localities for Zn/Ca, Sr/Ca and Ba/Ca ratios. Significant inter-annual differences at one Exuma Sound location was restricted to Ba/Ca ratios. Discriminant function analysis correctly classified 86% and 95% of the Belize and pooled Exuma sites, respectively. Otoliths from Belize were characterized by low Zn/Ca and high Ba/Ca and Pb/Ca ratios compared to otoliths from fish collected in Exuma Sound. Although differences in Ba levels may be related to upwelling at Glover Reef, more data are needed to definitely link otolith composition with regional differences in water chemistry.
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  • 2
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    Springer
    Pharmacy world & science 10 (1988), S. 93-95 
    ISSN: 1573-739X
    Keywords: Anthracyclines ; Chemistry ; Drug stability ; Mitomycins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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  • 3
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    Springer
    Pharmacy world & science 10 (1988), S. 101-116 
    ISSN: 1573-739X
    Keywords: Chemistry ; Chromatography ; Etoposide ; Immunoassay ; Metabolism ; Podophyllotoxin ; Pharmacokinetics ; Teniposide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Etoposide (VP 16-213) and teniposide (VM 26) are semisynthetic epipodophyllotoxin derivatives active against a variety of tumours. The clinical efficacy has led to an increasing interest in these compounds. This review presents information on the mechanism of action, biochemical pharmacology, bioanalysis, metabolism and pharmacokinetics of etoposide and teniposide.
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  • 4
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 291-293 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the process of developing a high-sensitivity negative chemical ionization gas chromatographic/mass spectrometric assay for brain and cerebrospinal fluid (CSF) levels of quinolinic acid (QUIN, 2,3-pyridine dicarboxylic acid), (18O4)QUIN was prepared. Its properties as an internal standard were compared with those of the structural isomer 2,4-pyridine decarboxylic acid (2,4-PDC) previously used by others. All oxygen atoms in QUIN were labeled by heating in 3N HCl/(18O)water for 48 h at 80°C. Back-exchange of (18O4)QUIN was prevented during derivatization to an electron-capturing dihexafluoropropanol ester by using trifluoroacetylimidazole as catalyst instead of perfluroacyl anhydrides. When mixtures of QUIN and (18O4)QUIN and/or 2,4-PDC were followed through a procedure to isolate and quantify brain and CSF QUIN, the variability in the ratio of QUIN:2,4-PDC was greater than for QUIN:(18O)QUIN. We conclude that (18O)QUIN is the preferred internal standard in gas chromatographic/mass spectrometric quantification of brain and CSF QUIN, and that (18O)-labeled carboxylic acids may be esterified effectively without back-exchange using acylimidazole reagents.
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  • 5
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 305-310 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polycyclic peptide antibiotic, Nisin, has been analysed by plasma desorption mass spectrometry using two different sample preparation techniques and two versions of the commercial plasma desorption mass spectrometer, and a prototype with high resolving power. The spectra obtained allow identification of a major component and two minor analogues. Extensive fragmentation is observed in samples prepared by the electrospray technique, whereas only ions indicating the molecular weight are produced when the sample is adsorbed on nitrocellulose.
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  • 6
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 369-374 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 13C enrichment of the carboxyl carbon of leucine was measured by isotope ratio mass spectrometry after conversion to CO2 by reaction with ninhydrin in a Vacutainer and cryogenic purification using the Finnigan MAT Breath Gas Analysis System designed for processing 13C breath test samples. The sources of error which arise with submicromole samples are examined and corrections provided for suboptimal mass spectrometer signals and contamination of the evolved CO2 with CO2 from the reaction medium. The main limitations to the accuracy and precision of the method are not instrumental but arise from the contamination with residual CO2 in the reaction medium, and this sets a lower limit of around 0.25 μmol leucine on the practical sample size. This is an improvement of about five-fold on the previous manual method of CO2 isolation.
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  • 7
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The fragmentation pathways of methyl abscisate and its 2E isomer in methane positive ion chemical ionization (PICI) and methane negative ion chemical ionization (NICI) mass spectrometry have been elucidated using isotopically labelled analogues. It is shown that in PICI the most abundant ions are formed by the loss of water, methanol, both methanol and water and of methyl formate. The PICI mass spectrum of methyl 2E abscisate differs significantly in that the loss of water is much less important. In NICI, the most abundant ions from methyl abscisate are due to the molecular anion, [M - H2O]- and [M - CH3OH]-. It is shown, however, that the methyl ester methyl is not lost in this last fragmentation. Two other significant ions contain the side chain and the ring of methyl abscisate, respectively. In contrast, the NICI mass spectrum of methyl 2E abscisate differs principally in showing an abundant loss of a hydrogen atom.
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  • 8
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 459-460 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 9
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    Biological Mass Spectrometry 15 (1988), S. 99-104 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dehydroepiandrosterone sulphate (DHAS) has been quantified in human blood serum by fast atom bombardment (FAB)/tandem mass spectrometry of immunoadsorption extracts. FAB of DHAS yielded abundant ions corresponding to the intact steroid sulphate; these were selected by a double-focusing mass spectrometer prior to collisionally activated decomposition in a quadrupole collision cell and mass analysis by a quadrupole mass filter. [HSO4]- (m/z 97) was the sole prominent daughter ion. For quantitative analyses the quadrupole mass filter was set to transmit m/z 97 and a narrow-range magnet scan yielded a spectrum of parents, including m/z 367 and 369, corresponding to DHAS and the (2H2)-analogue (used as internal standard), respectively. Serum concentrations by this procedure were in good agreement with data obtained by gas chromatographic/mass spectrometric analyses of DHA heptafluorobutyrate, formed by direct derivatization of the steroid sulphate.
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  • 10
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 659-667 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The problem of reproducing electron capture negative ion mass spectra has been addressed by studying parameters that affect negative ion abundance on a Hewlett Packard 5985B mass spectrometer. Parameters affecting negative ion formation in the ion source, such as ion source temperature, pressure, sample concentration and electron energy, were studied in conjunction with the effect of lenses used to extract and transmit ions to the quadruples. From these experiments, it was found that, in addition to ion source temperature, the ion focus potential has the most dramatic effect on the abundance of molecular ions relative to fragment ions like Cl-. With proper control, it was found that the relative abundance of ions from decafluorotriphenylphosphine could be reproduced over a period of one year.
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  • 11
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 677-679 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 12
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 243-247 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 9-hydroxy-2-(U-2H3) methylellipticinium acetate (elliptinium) was synthesized with an isotopic purity of at least 96%. The structure was confirmed by proton nuclear magnetic resonance and direct probe fast atom bombardment mass spectrometry. A mixture of elliptinium and its deuterated analogue was administered intravenously to rats. In urine, after analysis by liquid chromatography/mass spectrometry (LC/MS), unchanged drug and N-acetylcysteinylelliptinium were found. In bile, after ion-pair extraction and LC/MS, the glutathionyl-elliptinium was found in addition to the parent drug and the N-acetylcysteine adduct.
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  • 13
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The direct determination of 2-(2-furoyl)-4(5)-(2-furanyl)-1H-imidazole (FFI), present in the acid hydrolysis products of B-poly(L-lysine) and B-albumin and which appears to be a key intermediate in the physicochemical changes occurring during the incubation of protein with glucose, has been carried out by collisional spectroscopy, using a commercial double-focusing, reverse-geometry mass spectrometer and without any sample derivatization and chromatographic separation procedures.
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  • 14
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for the screening, quantification and confirmation of a variety of estronenic substances in animal tissues. A solid-phase extraction technique combined with a liquid/liquid extraction allows for rapid sample preparation and high throughput for the following compounds in bovine liver, muscle and kidney: diethylstilbestrol, dienestrol, hexestrol, zeranol, taleranol, zearalanone, zearalenone, zearalenol, estradiol and estriol. Gas chromatography/mass spectrometry and selected ion monitoring is used for the determination with detection limits ranging from 50 to 150 ppt.
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  • 15
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 411-411 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 16
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The analysis of extracts from the South American plant Justicia pectoralis Jacq. permitted the identification, among other compounds, of coumarin, dihydrocoumarin, umbelliferone and 3-(2-hydroxyphenyl)propionic acid by gas chromatography/mass spectrometry (GC/MS); the acids and phenolic compounds were derivatized with diazomethane. GC/MS of simple coumarins, phenylpropionic acids and their hydroxylated isomers was performed after derivatization through methylation and trimethylsilylation; these results may be useful for the identification and quantification of these compounds in other biological materials.
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  • 17
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    Biological Mass Spectrometry 15 (1988), S. 419-427 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The fast atom bombardment mass spectra of 24 α-amino acids have been studied. These include the mass spectra as well as the metastable ion MI and collisional activation CA spectra of [M + H]+ and [M - H]- ions. The extent of the common neutral losses as NH3, H2O and CO2H2 in the positive ion spectra is governed by the nature of the side chain. The relationship between the fragmentation behaviour of the negative ions and the presence of particular functional groups is less obvious. Mixtures of amino acids in glycerol show pronounced surface effects.
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  • 18
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A conventional bore liquid chromatograph has been interfaced to quadrupole and magnetic sector mass spectrometers configured for fast atom bombardment ionization via a continuous flow FAB probe. It is shown that post-column addition of FAB matrix and in-line ultraviolet detection facilities do not significantly compromise chromatographic integrity and that high quality mass spectra are obtainable from such FAB LC/MS studies.
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  • 19
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    Biological Mass Spectrometry 15 (1988), S. 193-204 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method which involves the use of tandem mass spectrometry (MS/MS) for the identification of drug metabolites has been demonstrated with a triple quadrupole mass spectrometer. The method is based on the fact that metabolites usually retain various substructures of the original drug molecule. MS/MS is capable of rapidly identifying molecules with characteristic substructures without prior separation. It is shown that this method makes it possible to postulate possible drug metabolite structures rapidly and systematically without the use of standards. The MS/MS method, as it was applied to the identification of the metabolites of a new antiepileptic drug, zonisamide, is discussed. In this case it was possible to identify isomeric metabolites due to their differences in vaporization times off the probe and their different daughter spectra. The complementary uses of the neutral loss and parent scans for the determination of the site of metabolism is demonstrated. A new figure of merit, the limit of identification, is introduced. The amount of the epoxide metabolite of carbamazepine necessary for its reliable identification in urine was shown to be 0.4 ng/μl. The application of various techniques to confirm preliminary findings with this MS/MS method are described.
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  • 20
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    Biological Mass Spectrometry 15 (1988), S. 239-242 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 21
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Self-chemical ionization Fourier transform ion cyclotron resonance (FT-ICR) mass spectra are reported for bases, nucleosides, and alkylated and exocyclic adducts of bases and nucleosides. The technique always produces a protonated molecular ion and in the majority of cases this is a single, intense peak. Analysis of a base mixture and a nucleoside mixture demonstrates the technique as an excellent method to identify the constituent compounds qualitatively. The high resolution capabilities and tandem mass spectrometric techniques (msn) in FT-ICR are discussed with respect to developing the technique as a future method to identify and characterize nucleic acid constituents, specifically adducts.
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  • 22
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    Biological Mass Spectrometry 15 (1988), S. 547-551 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nucleotides of the structure P1,Pn-di(adenosine-5′)-n-phosphate (n = di- through penta-) in the form of salts, and P1,P4-di(guanosine-5′)tetraphosphate sodium salt have been analyzed by fast atom bombardment (FAB) mass spectrometry. A 0.2 molar solution of p-toluenesulfonic acid in glycerol has been evaluated as a matrix. In this matrix, the metal ions of the nucleotide salts are readily exchanged for protons, resulting in a simple spectrum with only one peak in the molecular ion region corresponding to the free phosphoric acid of the nucleotide plus or minus a proton (positive or negative mode), instead of the multiplicity of peaks arising from a series of metal and matrix adduct ions found with glycerol as matrix. The detection limit for analytes using this matrix is improved by a factor of ten compared to glycerol alone. It appears that the high acidity and the surfactant properties of p-toluenesulfonic acid both contribute to this result. Useful spectra are obtained from 250 ng of each of the above mentioned nucleotides, with the detection limit being somewhat lower in the positive mode. However, both positive and negative FAB spectra are useful and the results are complementary.
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  • 23
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact mass spectra of poly(trimethylsiloxy) derivatives of polyenic long-chain carboxylic acids containing a conjugated diene unit clearly locate all double bonds. Abundant, diagnostic fragment ions arise from cleavage of the bonds at the positions of the original double bonds, combined with loss of a molecule of trimethylsilanol for every two vicinal trimethylsiloxy groups, with the exception of similar ions formed by rupture of an original conjugated double bond and containing the other conjugated double bond, which are weak or absent. The method was applied to several alkadienoic, alkatrienoic and alkatetraenoic acids containing a conjugated diene unit.
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  • 24
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Long-chain unsaturated fatty acids (UFA) can easily be converted on a microgram scale to the corresponding 2-alkenyl-4,4-dimethyloxazolines by condensation with 2-amino-2-methylpropanol (AMP). These modified molecules with a ‘hidden’ carboxyl group have been proved to be a class of useful derivatives for gas chromatography/mass spectrometry (GC/MS) of UFA mixtures. While possessing very good GC characteristics, the title compounds show regular, well-recognizable diagnostic ion peaks of the double bond position in the chain. Detailed description of the method as well as electron impact (E1) mass spectra of derivatives resulting from mono-, di and polyenoic (maximally containing six double bonds) acids are presented.
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  • 25
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    Biological Mass Spectrometry 15 (1988), S. 63-66 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A stable isotope assay for the quantification of debrisoquine (1) and its major urinary metabolite 4-hydroxydebrisoquine (2) is described. The method consists of extractive derivatization of 1 and 2 by use of 1,3-diketones, chiral derivatization of the 4-hydroxy group of 2, and gas chromatography/negative ion chemical ionization mass spectrometry in the presence of deuterated analogues of 1 and 2. In comparison with synthetic R-(-)-2 and S-(+)-2 it is shown that in vivo benzylic 4-hydroxylation of 1 is highly stereoselective, leading predominantly to S-(+)-4-hydroxydebrisoquine (enantiomeric excess ≥90%).
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  • 26
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    Biological Mass Spectrometry 15 (1988), S. 75-77 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [MH]+ ions of peptides are degraded in one step to acyl ions, indicating the presence of different [MH]+ species. In contrast to protons, cations are added mainly at the carboxylate function of a peptide zwitterion. These species are degraded by loss of the C-terminal amino acid in the form of CO and an imine.
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  • 27
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method for qualitative and quantitative analysis of trace amounts of quaternary organoarsenicals such as arsenocholine and acetylarsenocholine has been developed. The method is based on pyrolysis, gas chromatography/mass spectrometry and use of deuterium-labelled internal standards. Arsenocholine and acetylarsenocholine have been estimated in fish from arsenic-polluted brackish water and compared with the same species of fish from unpolluted water. The investigation also includes some fish and crustacea from marine water. The presence of arsenocholine and acetylarsenocholine in different aquatic organisms indicate the existence of a general metabolic pathway for these compounds in aquatic ecosystems.
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  • 28
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    Biological Mass Spectrometry 15 (1988), S. 89-98 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of 35 steroid conjugates (sulfates and glucuronides) and bile salts were investigated by using fast atom bombardment and tandem mass spectrometry. Collisional activation of the [M - H]- anions of sulfate conjugates and bile salts predominantly yields fragment ions arising by reactions occurring remote from the charge site. These reactions are sometimes sensitive to differences in stereochemistry at positions remote from the charge site and are useful for positional isomer differentiation. On the other hand, collisional activation of the [M - H]- anions of the glucouronide conjugates leads primarily to charge-driven fragementations.
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  • 29
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electron impact mass spectra of methyl ester/methoxime/trimethylsilyl ether derivatives of thromboxane B2 (TxB2) and 2,3-dinor-TxB2 and methyl ester/trimethylsilyl ether derivative of 11-dehydro-TxB2 are presented. Additionally, the derivatives of (2H4)-thromboxanes and methyl ester (2H3)-methoxime/trimethylsilyl ether derivatives of TxB2 and 2,3-dinor-TxB2 and (2H3)-methyl ester/trimethylsilyl ether derivative of 11-dehydro-TxB2 were investigated. Collision-induced dissociation mass spectra of the most intense parent ion in the high-mass region were taken. Collisionally activated decomposition mass spectra of the [C(12)-C(20)]+ ion of TxB2 and 2,3-dinor-TxB2 show an intense but not specific daughter ion, whereas the collison-induced dissociation mass spectrum of the [M - (C(16)-C(20)]+ ion of 11-dehydro-TxB2 results in the formation of numerous daughter ions.
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  • 30
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    Biological Mass Spectrometry 15 (1988), S. 183-183 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 31
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    Biological Mass Spectrometry 15 (1988) 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 32
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    Biological Mass Spectrometry 15 (1988), S. 183-184 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 33
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Steviol (ent-13-hydroxykaur-16-en-19-oic acid), the aglycone of various plant-derived glycoside sweeteners consumed by human populations, is known to be mutagenic toward Salmonella typhimurium strain TM677 when metabolically activated using a 9000 × g supernatant fraction derived from the liver of Aroclor 1254-pretreated rats. Mass spectral analysis of this diterpenoid and some analogs revealed characteristic patterns reflecting differential stereochemistry at the C/D rings and variations in the nature of the substituents present. Such information has been used to help identify several in vitro metabolites of steviol in conditions known to produce a mutagenic response, when analyzed by human populations, is known to be mutagenic toward Salmonella typhimurium strain TM677 when metabolically be allylic oxidation and epoxidation. 15-Oxosteviol, a product of oxidation of the major steviol metabolite, 15α-hydroxysteviol, was found to be a direct-acting mutagen.
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  • 34
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Positive ion fast atom bombardment mass spectra of maltooligosaccharides reductively aminated with 2-aminopyridine (Gn-AP) contain abundant [M + H]+ ions. Determination of G2-AP and G3-AP produced from G5-AP by the action of α-amylases, based on the abundance of their [M + H]+ ions relative to that of cellobiose reductively aminated with 2-amino-6-methylpyridine as the internal standard, allowed rapid and reproducible assay of these enzymes. It was advantageous for clinical investigation that the proportion of pancreatic and salivary α-amylase activities could be determined.
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  • 35
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A multi-stage screening and identification scheme for the diagnosis of inborn errors in amino acid, fatty acid, carbohydrate and intermediary metabolism is described. The method is based on a computerized analysis of data obtained with dual-column gas chromatography/FID (GC/FID) and gas chromatography/mass spectrometry (GC/MS) profiling of urinary organic acids. It involves: (1) isolation of the compounds by solvent or solid-phase extraction; (2) conversion into trimethylsilyl (TMS) or TMS-oxime derivatives; (3) GC/FID analysis on SE-52 and OV-1701 capillary columns; (4) tentative identification by comparing the methylene unit (MU) values on both columns with a user-built library of reference compounds; (5) quantitative evaluation of the excretion profile; and (6) analysis by GC/MS of samples with an abnormal profile using an automated peak identification programme.
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  • 36
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 357-357 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 359-363 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact (EI) mass spectra (75 eV) of the new carboxylic acid ionophore griseochelin and some of its derivatives are discussed. The mass spectral fragmentation was studied using exact mass measurements and deuterium labelling. Furthermore, the negative ion mass spectra (2-4 eV) of these compounds are compared with their EI mass spectra.
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  • 38
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 367-380 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New telechelic ionomers with zinc and sodium sulfate salt terminal groups on hydrogenated polybutadiene (HPB) backbones (I) were prepared from hydroxyl-terminated hydrogenated polybutadiene (HTHPB) of three different molecular weights (1350, 2100, and 3200 g/mol). Quantitative acid-base titration, elemental analysis, and NMR spectroscopy were used to verify the structure, and further characterization included differential scanning calorimetry (DSC) and solution viscometry. The DSC results indicated that the ionomers are free of impurities within the limit of the resolution of the method. Glass transition temperatures determined by DSC indicated that the elevation in glass transition temperature by ionic crosslinking was most strongly dependent on the molecular weight of the backbone of the telechelic ionomer. The solution viscometry results showed that the sulfation reaction did not cause either covalent crosslinking or chain scission. Furthermore, the solubility characteristics of the sulfate-terminated hydrogenated polybutadiene (STHPB) oligomers were shifted towards a preference for polar solvents by the presence of salt groups. The lower molecular weight ionomers of the series showed polyelectrolyte-like extension at very dilute concentrations in polar solvents. The onset of polymer gelation in hexane was observed for the ionomers which had the highest molecular weight backbones.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 9-18 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Latexes stabilized by poly(N-isopropylacrylamide) (polyNIPAM) were prepared by polymerizing NIPAM in the presence of polystyrene and polystyrene-butadiene latex or by styrene emulsion polymerization in the presence of NIPAM. In 0.01 M CaCl2 polyNIPAM stabilized latexes exhibited critical flocculation temperatures in the range 32-35°C, which is approximately equal to the lower critical solution temperature of polyNIPAM in water. Partial substitution of NIPAM with some acrylamide (AM) gave higher flocculation temperatures. Coagulation studies with cleaned latex indicated that the polyNIPAM or polyNIPAM-co-AM polymer chains were anchored to the latex particle surfaces.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 43-59 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Copolymers of ethylene and chlorotrifluoroethylene that contain small amounts of units derived from perfluorohexylethylene show improved resistance of thermal stress cracking. This is a consequence of effects of these units on structural parameters of both the crystalline and amorphous phases. Those of the crystalline phase entail growth and organization of lamellae, whereas those of the amorphous phase are related to conformation and packing of polymer chains. The crystalline phase consists exclusively of alternately arranged units of ethylene and chlorotrifluoroethylene. The amorphous phase is characterized by chain segments composed of randomly distributed units derived from ethylene, chlorotrifluoroethylene, pairs of these two units, and units derived from perfluorohexylethylene.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 615-626 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Natural rubber was isomerized by two methods that involved either dehydrobromination of hydrobrominated natural rubber or heating natural rubber with butadiene sulfone. The 13C-NMR spectra of the methylene region of isomerized natural rubber was interpreted in terms of dyad arrangements for which assignments were made by calculating chemical shifts according to three different published methods. One method [Gronski, Murayama, Cantow, and Miyamoto, Polymer, 17, 358 (1976)] gave the best overall agreement with the experimental chemical shifts; another [Sato, Ono, and Tanaka, Polymer, 18, 580 (1977)] was better for C-1 and C-3 methylene carbon atoms; and still another [Khatchaturov, Dolinsky, Prozenko, Abramenko, and Kormer, Polymer 18, 871 (1977)] gave results which deviated considerably from the other methods. From 13C-NMR intensity measurements it was shown that the elimination of HBr from hydrobrominated natural rubber occurred by a random process. Contrary to literature reports, it was found that the sulphur dioxide catalyzed isomerization of natural rubber was accompanied by a significant amount of double bond migration; a possible reaction scheme was proposed.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 627-636 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymeric arylantimony(V) oxides [poly(ArSbO2), Ar = phenyl, p-chlorophenyl (CPh), and p-methylphenyl (Tol)] were employed as catalysts for the polymerization of oxirane [ethylene oxide (EO)] and also substituted oxiranes [propylene oxide (PO), 1,2-butylene oxide (BO), and epichlorohydrin (ECH)]. The polymerization of EO by ArSbO2s proceeded 3-60 times faster than that by the other organoantimony and -tin compounds such as triphenylstibine oxide (Ph3SbO) and arenestannoic acids (ArSnO2H), respectively. Apparent activation energy for the polymerization of EO was estimated as 13.7, 13.3, and 13.6 kcal/mol for PhSbO2, TolSbO2, and CPhSbO2, respectively. The results of the polymerization as well as 1H-, 13C-, and 17O-NMR spectroscopy suggested that the polymerization was initiated by ArSbO2 or Ar2Sb2O4 fragments, which was derived from a nucleophilc solvation of the polymeric ArSbO2 by oxiranes in situ.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 653-656 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 637-651 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The double bonds of natural rubber latex (stabilized by a nonionic surfactant) were reacted with an approximately equimolar amount of performic acid at room temperature with a limited amount of formic acid present. Product analysis by 1H-NMR during the course of the reaction showed that 69-90% epoxidation occurred before the advent of ring opening and ring expansion to produce furanized rubber; hence the rate of epoxidation was greater than the rate of furanization. Indeed, at lower concentrations of formic acid and rubber latex, epoxidation occurred to 90% and furanization was prevented; it was subsequently brought about by the addition of a catalytic amount of orthophosphoric acid. Increased formic acid concentration caused early coagulation of the modified rubber latex. By 1H- and 13C-NMR, it was found that the furanized rubber probably consisted of tetrahydrofuran rings linked together by C—C bonds at positions adjacent to the hetero atom and contained a terminal hydroxy group. The number average sequence length was 2-9, but only the sample with an average sequence length of 9 was effective as a cation binder.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 657-675 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A number of derivatives of ω-alkenoates were synthesized in preparation for the synthesis of functional polymers based on α-olefins. For the preparation of most of the methyl esters, the regular esterification of ω-alkenoic acids, specifically 10-undecenoic acid with methanol and sulfuric acid as the catalyst, was most effective. For the preparation of the tert-butyl- and 2-ethylhexyl esters of 10-undecenoic acid, the acid chloride route was found to be most convenient, whereas for the preparation of the corresponding esters of 5-hexenoic acid, our method of choice was the synthesis via the imidazolyl derivative of the acid. 2,2,2-Trifluoroethyl 10-undecenoate and the 2,2-dimethyloxazolidine derivative of 10-undecenoic acid were prepared from the acid and 2,2,2-trifluoroethanol or 2-amino-2-methyl-propanol with p-toluene sulfonic acid as the catalyst. Esters of phenol, 2,6-dimethylphenol, and 2,6-diphenylphenol were synthesized from 3-butenoic and 10-undecenoic acid with trifluoroacetic anhydride.
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  • 46
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 235-245 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aromatic polyamides were prepared from systematically halogenated terephthalic acids with hexamethylene diamine, piperazine, 4,4′-diaminodiphenylether and p-phenylene diamine by interfacial or low temperature solution polycondensation. The halogenated terephthalic acids used have mono-, di-, or tetra-substituted fluorine, chlorine, or bromine atoms on the benzene ring. The nonhalogenated terephthalic acid was also used for the comparison. The effects of halogen substitution on the benzene ring on the synthesis and some properties of polymers were examined. Reduced specific viscosity decreased in the order F 〉 Cl 〉 Br by halogen substitution. The incorporation of halogen substituents on the ring led to a decrease of crystallinity and fluoro-substituents hindered the crystallization more strongly. The melting point (Tm) decreased in the order F 〉 Cl 〉 Br by mono-substitution, and Br 〉 Cl 〉 F by di-and tetra-substitution. The change of Tm caused by the difference of the number of halogen substituents differed depending on the rigidity of polymer chains. The flame-retardancy estimated by thermogravimetry, self-ignition, and flash-ignition test increased with increasing halogen content of the polymers. Solubility increased remarkably by halogen substitution. The peak temperature of tan δ decreased by halogen substitution. Some discussion was made on these effects of halogen substitution.
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  • 47
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 301-311 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electro-initiated polymerization of acrylonitrile initiated by the anodic oxidation of an aqueous acid solution (80% HOAc + 20% H2O) containing Mn(OAc)2 · 4H2O/CNCH2COOH has been investigated in the 30-40°C temperature range. The kinetics and mechanism of the process has been investigated as a function of variables and a suitable mechanism proposed. From the experimental observations the rate of polymerization is seen to be proportional to [An]1.5I0.5[Mn+2]0.5 and [CAA]0.5. The rate of polymerization gradually decreases at a higher applied current. The rate was independent of [CAA]0.5. The rate of polymerization gradually decreases at a higher applied current. The rate was independent of CAA at high concentration. The average degrees of polymerization (Pn) increases with increasing AN and decreasing [CAA], [Mn+2] and applied current, I. The initiation is due to the anodic oxidation of Mn+2-CNCH2COOH complex. Both the initiation of polymerization by the primary radical, viz., CN—CḢ—COOH as well as the oxidation of the primary radical at the electrode are equally significant reactions and neither can be neglected in comparison with the other. Predominant mutual termination accounts for all the observed data.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 335-340 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 355-366 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics and mechanism of polymerization of methacrylic acid (MAA) and ethyl acrylate (EA) initiated by the redox system, Mn3+-thiodiglycolic acid (TDGA) were investigated in the 15-35°C temperature range. The polymerization kinetics of both the monomers followed the same mechanism, viz., initiation by primary radical and termination by Mn3+-thiodiglycolic acid complex. The rate coefficients ki/k0 and kp/kt were related to the monomer reactivity and polymer radical reactivity, respectively. It was observed that both monomer reactivity and polymer radical reactivity followed the same order, viz., EA 〉 MAA. The polymer radical reactivity varied inversely with the Q values of the monomers.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 247-254 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diepoxides and in-chain carbonate groups react readily in the presence of quarternary ammonium salts, although reaction is not observed without this catalyst. Two moles of epoxide react with each mole of carbonate. When diepoxides and polycarbonates are reacted, a three-dimensional network of chains crosslinked with carbonate groups is produced; the crosslink density is controlled by adjusting the epoxy/carbonate ratio. Tertiary amines and alkoxides also catalyze the epoxy/carbonate reaction, but these have the undesirable attribute of promoting epoxy polymerization. The presence of oligocarbonates accelerates the epoxy-amine reaction.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 267-274 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-Ethoxy-2,2,2-trifluoroethyl esters of acrylic (I) and methacrylic (II) acids were synthesized from 1-ethoxy-2,2,2-trifluoroethanol and acryloyl- and methacryloylchloride, respectively, and their densities, mass, 1H- and 13C-NMR spectra were measured and the rate constants of hydrolysis were determined. Poly(I) and poly(II) were prepared by radical homopolymerization; the rates of polymerization, specific volume contractions in polymerization, limiting viscosity numbers, average number degrees of polymerization, temperature dependences of the heat capacities both in glass and liquid state, glass transition temperatures, and the initial temperature of the spontaneous thermal decomposition of homopolymers were determined. The monomer reactivity ratios of the styrene (S) copolymerizations, S—I and S—II, and the Alfrey-Price copolymerization constants e and Q for I and II were calculated from the composition of copolymers of I and II with styrene.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 285-299 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The octameric oligomers of 1-(N-substituted-carbamoyl)-aziridine, i.e., N-ureanized-oligo-ethylenimines, form Cu(II) complexes. When the N-substituents are phenyl(1, 3), methyl(2), and p-tolyl(4) groups, the main portions of the Cu(II)-complexes are binuclear. The binuclear oligomer-Cu(II) complexes showed characteristic properties of photo-reduction of Cu(II) species, giving rise to stable yellow Cu(I) species. The ease of photo reduction strongly depends on the oligomer structures, especially on the nature of the pendant-urea groups, i.e., 4 〉 1,3 〉 2. In the series of aromatic type urea-oligomers, highly stable photo-radicals were observed in ESR. By using an optically active oligomer (3) the molecular requirements for these characteristic properties were investigated with circular dichroism and cyclic voltammometry. And one of the plausible structures was deduced as the model of binuclear Cu(II) sites surrounded by oligomeric environments.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 321-327 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The copolymerizations of phenyl-4′-vinylphenylbutadiyne (PVPB) with styrene and methyl methacrylate were carried out under various conditions. PVPB was more readily incorporated in copolymerization than the comonomers, but the diacetylenic group of PVPB interacted with the propagating radical, decreasing the polymerization rate and the molecular weight of copolymer. When the polymerization system became very viscous, crosslinking took place giving light green luminescent gels. The thermal behaviors of copolymers were also studied.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 343-353 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vinylbenzyl acetate was synthesized in yields greater than 80% via the reaction of vinylbenzyl chloride with potassium acetate. Radical copolymerization of the monomer with styrene and methylmethacrylate were studied at 60°C. Reactivity ratios determined from FT-IR analysis of low conversion copolymerizations with styrene (M1) were r1 = 0.78 ± 0.07 and r2 = 1.33 ± 0.13. Polymers and copolymers of vinylbenzyl acetate were found to completely hydrolyze in dioxane/water/base solution to yield hydroxymethyl functionality. Size exclusion chromatography studies indicated that the hydrolysis proceeded without crosslinking. This procedure is a useful method for the introduction of hydroxyl functionality on polymers and avoids crosslinking problems common in previously reported methods.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 381-391 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A procedure for the preparation of new block copolymers composed of a hydrophobic block of polystyrene, a hydrophilic spacer-block of poly(ethylene oxide) and a bioactive block of heparin was investigated. Polystyrene with one amino group per chain was synthesized by free radical oligomerization of styrene in dimethylformamide, using 2-aminoethanethiol as a chain transfer agent. This amino group was used in the coupling reaction with amino-telechelic poly(ethylene oxide) to produce an AB type diblock copolymer with one amino group per polystyrene (PSt)-poly(ethylene oxide) (PEO) chain. The amino-semitelechelic oligo-styrene was converted into the isocyanate-semitelechelic oligo-styrene using toluene 2,4-diisocyanate and subsequent coupling with H2N-PEO-NH2 afforded AB type block copolymers with terminal amino groups. The coupling of PSt-PEO-NH2 with heparin was performed in a DMF-H2O mixture, first by activating the heparin carboxylic groups with EDC at pH 5.1-5.2 and subsequently reacting the activated carboxylic groups with the amino groups of the PSt-PEO-NH2 at pH 7.5. Depending on the molecular weights of the diblock copolymer used 25-29% w/w heparin was incorporated. These polymers will be further evaluated for their blood-compatibility.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 419-427 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to obtain polysiloxanes capable of forming a film, the preparation and properties of allyldimethylsilylated silicic acid was investigated. The reaction in variable molar ratios of allyldimethylchlorosilane to silicic acid gave partially silylated silicic acids with different degrees of silylation. They provided not only fibrous polysiloxanes but also films from concentrated polymer solutions. Spinnability and film formation depended on the solvent, degree of silylation, molecular weight, and allyl group.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 457-464 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Supports were obtained by the interaction of C4H9MgCl with the reaction mixture of AlCl3 and CH3Si(OC2H5)3 or Si(OC2H5)4 (Mg/Al/Si = 2/1/1). With the combination of Al(C2H5)3 and methyl-p-toluate, immobilized titanium catalysts prepared by the treatment of the supports with TiCl4 and ethylbenzoate showed extraordinary high activity and stereoregularity in the polymerization of propylene.1 By the study of the reaction of AlCl3 with CH3Si(OC2H5)3, the elemental analysis and powder x-ray diffractometric measurements of the supports, it was found that the supports comprised of Cl, Mg, Al, and Si atoms, OC2H5 groups, C4H9 groups, and ethers, and that they were amorphous solids to the extent that the x-ray diffraction peak assigned to the 003 plane in MgCl2 crystals completely disappeared.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 901-911 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of various substituted amines on the polymerization of methyl methacrylate initiated by ferric laurate - amine as the initiator system has been studied in carbon tetrachloride medium at 60°C. Amines used are n-butyl amine, di-n-butyl amine. The rate of polymerization is found to follow the order: tertiary 〉 secondary 〉 primary amine. From the detailed kinetic studies it was found that the overall polymerization rate can be expressed by the equation: \documentclass{article}\pagestyle{empty}\begin{document}$ R_p = \frac{{k_p }}{{k_t^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} }}(k_1 f)^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} [{\rm Monomer}][{\rm Fe}^{3 + } ]^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} [{\rm Amine}]^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} $\end{document} The relative activity of the different amines has been found to be dependent on the relative electron-donating tendency of the substituents present in the amine. The mechanism of the polymerization is discussed on the basis of these results, and various kinetic constants are evaluated.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 959-962 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 60
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 965-971 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A general method for estimating kinetic parameters in polymerization reactions using Monte Carlo simulation to represent the models of the reactions is developed. From a statistical point of view, the procedure is a Bayesian one in which a posterior probability density surface (PPDS) is calculated for points on a grid in the parameter space. A smoothing function is fitted to the PPDS, then a posterior probability region, which is similar to a confidence region, is calculated for the parameters. An application to a relatively trivial example, the Mayo-Lewis copolymerization model is shown in detail. Many other potential applications are suggested.
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  • 61
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2345-2354 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High performance linear AA-BB and A-B polyamides were generated using polymerization schemes that gave polymers in higher yields and having better performance than previous methods. Polymers were characterized with FTIR, solution and solid-state 13C-NMR and showed the incorporation of aryl, alkyl, and alkenyl linkages in the polymer backbone. Thermal analysis showed that a significant weight percent of the polymers remained at 1000°C.
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  • 62
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 865-883 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel route for the thermal conversion of bis(phthalonitrile)monomers into metal-free phthalocyanine network polymers was investigated on the basis of a model study on the tetramerization reaction of 4-benzoylphthalonitrile and benzhydrol derivatives into metal-free phthalocyanine compounds. This procedure of conversion of phthalonitrile derivatives involved an oxidoreduction reaction initiated by the alcohol functional group of benzhydrol coreactant. The influence of molar ratio of phthalonitrile and benzhydrol functional groups, chemical environment of the benzhydrol reducing group has been studied by microcalorimetry and electronic spectroscopy. It was observed that the theoretical 4 : 1 phthalonitrile: benzhydrol molar ratio is respected and the reductive capacity of the benzhydrol group is increased by the electron withdrawing effect of its substituants.
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  • 63
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 885-900 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New phosphorus-containing homopolyurethanes were synthesized by reacting various diisocyanates such as tolylene diisocyanate, methylenebis(4-phenylisocyanate) and hexamethylene-1,6-diisocyanate with 1,4-bis[(dialkoxyphosphinyl)hydroxymethyl]benzene (BDAB). In addition, copolyurethanes containing approximately 3% phosphorus were prepared by copolymerization of these diisocyanates with an equimolar amount of BDAB - hydroquinone mixture. BDAB was less reactive towards diisocyanates than hydroquinone due to the electron-withdrawing inductive effect of the phosphinyl groups. The polymers synthesized were characterized by inherent viscosity measurements as well as by proton nuclear magnetic resonance (1H-NMR) and infrared (IR) spectroscopy. The spectroscopic examination of polymers did not provide evidence for crosslinking by allophanate groups. Differential thermal analysis (DTA) studies of polymers revealed that the incorporation of BDAB in polyurethanes altered their thermal decomposition mode by increasing the exothermicity due to pyrolysis. Thermogravimetric analysis (TGA) of polymers showed that the phosphorus-containing homopolyurethanes and copolyurethanes were thermally less stable than the corresponding common polyurethanes but afforded higher char yields. Determination of the limiting oxygen index (LOI) values showed that the phosphorus-containing copolyurethanes exhibited a higher fire resistance than that of common polyurethanes.
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  • 64
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 953-958 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 65
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1903-1909 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polar organic compounds either (1) inhibit the peroxide-catalyzed bulk homopolymerizations of both MAH and MMA at 80°C, (2) do not inhibit the polymerization of either MAH or MMA, or (3) inhibit the polymerization of MAH but not that of MMA. Compounds generally used as polymerization inhibitors or antioxidants inhibit the polymerizations of both MAH and MMA, presumably by interaction with peroxide decomposition products. Ketones, ethers, acids, esters, nitriles, imides, sulfones, sulfonates, sulfonamides, and acyl disulfides do not inhibit either MAH or MMA polymerization. However, amides, lactams, carbamates, amine oxides, phosphites, phosphates, phosphonates, phosphoramides, phosphine oxides, monosulfides, sulfoxides, aryl disulfides, and thiazyl disulfides inhibit the polymerization of MAH but not that of MMA. Inhibition presumably occurs as a result of electron transfer from the nitrogen-, phosphorous- or sulfur-containing electron donor compound to the MAH carbocation which is an intermediate in the polymerization of MAH.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1911-1918 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymerization of tetrahydrofuran (THF) (bulk) promoted by a free radical source, 2,2-dimethoxy-2-phenyl acetophenone (DMPA), in the presence of 4,4′-di-(methylphenyl)iodonium hexafluorophosphate was studied in detail. Rate dependence of the polymerizing system on both DMPA and the iodonium salt was studied dilatometrically. Rate saturation for the iodonium salt was attributed to the formation of iodobenzene, which may react with propagating cations to form an iodonium salt. DMPA was shown to be an efficient transfer agent in the cationic polymerization of THF. A transfer constant for DMPA was estimated to be 2.8 and, whilst the precise details of the overall mechanism cannot be deduced from the present results, it may result in functionalized polytetrahydrofuran chains having photochemically active end groups.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1919-1935 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of the solvent mixture chloroform/hexafluoroisopropanol (98 : 2 vol %) in the GPC-analysis of polyethylene terephthalate (PET) is described. PET-samples of different molecular weight have been prepared and characterized by light scattering, viscometry, and improved techniques of osmometry and end group titration. These well characterized samples were used in calibrating the GPC. The calibration with polydisperse standards was found superior to the universal calibration procedure in the solvent system chosen.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1937-1959 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Batch emulsifier-free copolymerizations of styrene (S) and butyl acrylate (BuA) have been performed for a S/BuA weight ratio = 50/50 in the presence of two types of functional comonomers [methacrylic acid (MAA) at different pHs] or potassium sulfopropylmethacrylate (SPM) and two initiators [potassium persulfate or 4-4′azobiscyanopentanoic acid (AZO)]. The use of AZO/MAA system results in the formation of polymer particles with only surface carboxylic end groups. The particle size of the final latexes can be adjusted with the MAA concentration, provided the polymerization is carried out at pH 〉 6.5. However, the higher the MAA concentration, the sooner the polymerization levels off in conversion. With the K2S2O8/SPM system, particles bearing only sulfate and sulfonate groups are produced and the polymerization is complete. In that case, the particle size of the final latexes is smaller than with the previous system and 30% of the SPM is fixed on the particle surface, instead of 10% with MAA. Using SPM, a too high functional monomer concentration results in the latex destabilization caused by the formation of a large amount of polyelectrolytes. Kinetic studies indicate that most of the functional monomer is incorporated onto the particle surface during the last 30% conversion of the polymerization. A tentative explanation of such a behavior is discussed, based on the existence of two polymerization loci in the latex system.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2517-2527 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four linear polyesters containing styrylpyridinium units were prepared from 2,6-bis(p-hydroxystyryl)pyridine and terephthalic acid, isophthalic acid, adipic acid, and sebacic acid, respectively. The polyesters are thermally stable in the 365 to 450°C range. The decomposition temperature is higher for aromatic polyesters, lower for their aliphatic analogs. The polyesters are photoreactive and crosslink on irradiation with UV. The crosslinking mechanism is 2 + 2 cycloaddition. The polyesters form protonated complexes with CF3COOH which absorb at longer wavelengths and are also photoreactive. The quantum yield of the photoreaction and the relative photosensitivities of the polyesters and their complexes were determined.
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1051-1061 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Novel polybenzimidazoles containing thiaxanthone heterocyclic units were synthesised from 2,7-thiaxanthonedicarboxylic acid-5,5′-dioxide and 2,8-thiaxanthonedicarboxylic acid-5,5′-dioxide and two aromatic tetramine hydrochlorides by PPA solution polycondensation in 60-70% yield. Two model compounds, 2,7-bis(2-benzimidazolyl)thiaxanthone-5,5′-dioxide and 2,8-bis(2-benzimidazolyl)thiaxanthone-5,5′-dioxide, were prepared and characterized by spectral methods. The polybenzimidazoles have inherent viscosities in the range 1.13-1.50 dL/g and decomposition temperatures of 495-560°C. The effect of thiaxanthone units on polymer properties are discussed.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1063-1076 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Novel polyamides containing heterocyclic thiaxanthone units were prepared by condensing 2,7-dichloroformylthiaxanthone-5,5′-dioxide and 2,8-dichloroformylthiaxanthone-5,5′-dioxide with various aromatic diamines, under low temperature solution polymerization conditions in DMAc. The model diamide, 2,8-ditolylcarbamylthiaxanthone-5,5′-dioxide was synthesised and characterized by spectroscopic methods. The polyamides were prepared in 70-80% yield and had inherent viscosity in the 0.36-0.73 dL/g range. The poyamides have decomposition temperatures in the 425-510°C range in nitrogen. The effect of thiaxanthone rings on polymer backbone on solubility, crystallinity, and thermal stability is also discussed.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1985-1988 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1991-2002 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Styrene/p-hydroxystyrene copolymers were prepared from copolymers of styrene and p-benzyloxystyrene by cleavage of the ether bond. Nuclear magnetic resonance spectroscopy was used to characterize the polymers before and after the ether cleavage reaction. Reactivity ratios were calculated by applying the method of least squares to data generated from the Fineman-Ross equation (r1 = 0.37, r2 = 0.28). The surface chemistry of centrifugally cast films of the homopolymers and the copolymers was studied by using electron spectroscopy for chemical analysis (ESCA). The Zisman contact angle method was used to determine the critical surface tension in air for each polymeric surface. Water contents of hydrated films were determined gravimetrically. The polar character of the surface was shown to increase to a small degree with an increase in the p-hydroxystyrene component. Polymers with high p-hydroxystyrene contents did not exhibit pronounced hydrogel character.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2003-2018 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two series of catalysts were made, one from MgCl2-A solution containing MgCl2, EH (2-ethylhexanol), and EB (ethyl benzoate) dissolved in decane and another from MgCl2-B solution containing MgCl2, EH, and phthalic anhydride which reacted to form the corresponding phthalic ester. Reactions of these solutions with TiCl4 with or without another ester produced a family of eight catalysts. They form two groups, one having monoesters as modifiers, and the other containing diesters as modifiers. The surface area, pore volume, x-diffractions, polymerization activity, and catalytic stereospecificity of these catalysts have been compared. The diester catalysts differ from the monoester catalysts in every respect. By comparison the corresponding member of the diester catalysts have half as much Ti per Mg, more than 10 times the pore volume, more than a 100-fold the surface area, about 50% more productivity, and greatly increased steroespecificity.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2019-2029 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A soluble monomer [methyl acrylate (MA)] and an insoluble monomer [butyl methacrylate (BMA)] were grafted onto cellulose by three types of ceric salts under both oxygen-free conditions and in the presence of oxygen. For comparison, Ce(IV) consumption during cellulose oxidation was also determined under similar reaction conditions. Slightly more Ce(IV) was consumed during cellulose oxidation in the presence of oxygen. During graft copolymerization of MA under oxygen-free conditions, the consumption of Ce(IV) was much lower than during cellulose oxidation regardless of the type of ceric salt employed. The opposite was observed in the presence of oxygen: much more Ce(IV) was consumed during grafting than during cellulose oxidation. The consumption of Ce(IV) in the graft copolymerization of BMA by ceric sulfate was nearly independent of reaction conditions and it was approximately the same as in cellulose oxidation. In the reaction initiated by ceric ammonium nitrate under oxygen-free conditions, less Ce(IV) was once again used up during grafting than during cellulose oxidation. However, the difference was much smaller than in the case of MA.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2031-2037 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The functionalization reaction of poly(styryl)lithiums (Mn = 1.3-9.9 × 103) with ethylene oxide in benzene proceeds quantitatively ( 〉 99%) to produce the corresponding hydroxyethylated polymer as determined by vapor phase osmometry, size exclusion chromatography, end-group titration, thin layer chromatography, and 1H- and 13C-NMR spectroscopy. 13C-NMR spectral analysis of the functionalized polystyrene with Mn = 1.3 × 103 was consistent with addition of only one ethylene oxide unit to poly(styryl)lithium, i.e., no evidence for ethylene oxide oligomerization was observed.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1671-1675 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1649-1657 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molecular weight studies of polyamic acids are complicated by polyelectrolyte effects. Although early work on the molecular weight determination of polyamic acids employed salts to suppress this polyelectrolyte effect, recent publications reveal that such salts can cause precipitation of polyamic acids from solution, however, a mobile phase consisting of 0.03M LiBr/0.03M H3PO4/1% vol THF in dimethyl formamide was reported to successfully suppress the noted polyelectrolyte effect without causing the precipitation of polyamic acid and give satisfactory size exclusion chromatograms using columns packed with “macro-porous” glasses. However, the development time was long (ca. 4 h) and considering the lability of the polyamic acids, the results must be viewed with skepticism. We find that use of a similar “mixed” mobile phase with Zorbax® PSM-Bimodal columns using size exclusion chromatography in the high performance mode (HPSEC) provides well resolved and reproducible chromatograms and molecular weight data with development times of 〈 15 min. Aside from the avoidance of long development times, which can lead to questionable results, this procedure permits the facile routine analysis of polyamic acid on a daily basis. The procedure has great utility as an analytical tool to support fundamental studies of polyamic acid chemistry and two examples of this application are given.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1677-1680 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1659-1669 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation of two model polymers of polynucleotides with linear polyurethane backbone and 2-(thymin-1-yl)propionyl or 2-(uracil-1-yl)propionyl group as grafted pendant are described. 2-(Thymin-1-yl)propionic acid (TPA) and 2-(uracil-1-yl)propionic acid (UPA) were grafted into partial imino functionalized polyurethane, poly[(β,β′-diethylene)amine methylene bis(4-phenylcarbamate)]-75 (PU-NH-75), at the secondary amino group through amide bonds with 1-hydroxybenzotriazole (HOBT) using the active ester technique. Two novel polymer models of polynucleotides, poly[(N-(2-(thymin-1-yl)propionyl)-β,β′-diethylene)amine methylene bis(4-phenylcarbamate)]-75 (PU-NT-75) and poly[(N-(2-(uracil-1-yl)propionyl)-β,β′-diethylene)amine methylene bis(4-phenylcarbamate)]-75 (PU-NU-75) were obtained. The imino polyurethane PU-NH-75 was produced from the partially deprotected N-Cbz imino polyurethane, poly[N-(benzyloxycarbonyl-β,β′-diethylene)amine methylene bis(4-phenylcarbamate)] (PU-NCbz) which was prepared by the polyaddition of 4,4′-diphenylmethane diisocyanate (MDI) with diol monomer N-benzyloxycarbonyl-β,β′-dihydroxyethylamine (CbzHEA). Selective N-protection of N-benzyloxycarbonyloxy-5-norbornene-2,3-bicarboximide (CbzONB) with β,β′-dihydroxyethylamine (HEA) gave the N-Cbz protected diol monomer HEA. The related monomer model compounds were also prepared by the same methods.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1189-1198 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crosslinking of LDPE resulting from reaction with dicumyl peroxide at 180°C is increased in the presence of maleic anhydride (MAH). The presence of electron-donating nitrogen-containing compounds (amides, lactams, disubstituted aromatic amines, and amine oxides), phosphorous-containing compounds (phosphites, phosphates, phosphonates, phosphoramides, and phosphine oxides) and sulfur-containing compounds (sulfoxides, aryl disulfides, and thiazyl disulfides) which inhibit the homopolymerization of MAH but not that of methyl methacrylate, prevents crosslinking and yields soluble PE containing MAH units. Crosslinking, due to coupling of PE· macroradicals formed by hydrogen abstraction from PE by excited MAH, is prevented by electron donation from the additive to the MAH+ cation which is present in the MAH+-MAH excimer as well as in the excimer which is appended to the PE.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1179-1188 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The diffusion coefficient of oxygen in poly(2-hydroxyethyl methacrylate) has been explicitly measured using an optical technique based on fluorescence quenching. This measurement represents the first explicit determination of DO2 in PHEMA. A diffusion coefficient of oxygen in PHEMA of 1.36 × 10-7 cm2/s at 20°C was obtained from this measurement. This value is shown to agree well with permeability data for PHEMA, the free volume theory of diffusion, and with values of DO2 that have been explicitly measured in other methacrylate hydrogels.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2099-2111 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Surfaces of low density polyethylene, high density polyethylene, and polystyrene have been modified by grafting with acrylic acid. Benzophenone and acrylic acid in the vapor phase were UV-irradiated in the presence of a polymer substrate. Grafting with acrylic acid took place in a thin layer on the surface, thus increasing the wettability of the polymer. After 5 min of irradiation, the contact angle against water had decreased to 20° for polystyrene and 50° for the polyethylene samples. ESCA measurements on samples irradiated for 5 min showed a 90% poly(acrylic acid) coverage of the surface for polystyrene, 63% for low density polyethylene, and 56% for high density polyethylene. Acetone or ethanol were used as carriers of monomer and initiator. Acetone was able to initiate grafting and was found to promote and direct grafting to the surface. The stability of the acrylic acid grafted surfaces was studied by contact angle measurements and ESCA. At room temperature, the grafted layer is confined to the surface, but when the material was heated in air the surface was reshaped into a hydrophobic one. The process was reversible. In aqueous surroundings at elevated temperatures the hydrophilic character of the surface was restored.
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2859-2862 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 86
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2873-2880 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ESCA has been used to characterize films deposited from perfluorobenzene and perfluorobenzene/benzene vapors during plasma polymerization and irradiation with vacuum ultraviolet light. The films deposited by both methods are shown to be essentially the same. This indicates that similar electronically excited states are involved in the formation of the precursors to deposition in both methods and that reaction mechanisms involving ions do not need to be considered for the plasma polymerization of the monomers investigated.
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  • 87
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2899-2905 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Novel phenyl-pendant aromatic polythiazoles having inherent viscosities of 0.3-1.3 dL/g were synthesized by the solution polycondensation of bis[4-(α-bromophenylacetyl)phenyl] ether with aromatic dithioamides or dithiooxamide in dimethylformamide at 60°C. The polythiazole having m-phenylene linkage was readily soluble in chloroform and m-cresol, and transparent flexible film could be cast from the chloroform solution. Glass transition temperatures of these polythiazoles were in the range of 210-250°C. They started to decompose at about 500°C in air with 10% weight loss being recorded at around 570°C.
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  • 88
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2917-2922 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aromatic polyamides (aramids) having inherent viscosities of 0.5-1.10 dL/g were prepared by the direct polycondensation of 1,1,3-trimethyl-3-(4-carboxyphenyl)indane-5-carboxylic acid with various aromatic diamines using triphenyl phosphite and pyridine as the condensing agents. Copolyamides were also prepared by a similar procedure from a mixture of the phenylindane diacid, terephthalic acid, and p-phenylenediamine. Almost all of the aramids were soluble in a variety of solvents such as N-methyl-2-pyrrolidone, pyridine, and m-cresol, and afforded transparent and tough films by the solution casting. These aramids and copolyamides had glass transition temperatures in the range of 290-355°C, and started to lose weight at 340°C in air.
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  • 89
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2941-2952 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Model reaction of bis(4-nitrophenyl) β-truxinate (BNPT) with aliphatic amines proceeded quantitatively at room temperature. Accordingly, polycondensation of BNPT with various diamines was carried out at room temperature or 80°C. During the polycondensation of BNPT with diamines, the precipitation of polymer or the observed gelation of polymerization solution occurred, which may limit the molecular weight of the polymer. On the other hand, the reaction of BNPT with 1,3-(4-piperidyl)propane (DPP) proceeded homogeneously to give the polymer with relatively high molecular weight, and the obtained polyamide (P-1e) showed excellent solubility in many solvents. The study of TG and DTA indicated that the obtained polymers were stable at lower temperature than around 270°C. The polymer prepared from the polycondensation of BNPT with hexamethylenediamine showed melting point and decomposition due to the imidation at 282°C. The photochemical reaction of these polymers was carried out in the film state. The irradiation of 254 nm light caused an absorption at 272 nm to appear and the molecular weight to decrease. This meant that the scission of cyclobutane ring in the main chain occurred to give cinnamamide structures. Also, the absorption at 272 nm decreased by the irradiation of 302.5 nm light. However, the UV spectrum of irradiated polymer did not agree with that of the original polymer. These results suggested that the dimerization of the resulting cinnamamide moieties occurred in the competition of their trans-cis-isomerization. On the other hand, the rate of scission of cyclobutane ring of P-1e was faster than that of the corresponding polyamide containing α-truxillamide structure.
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  • 90
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2991-2996 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fluorine-containing graft copolyamides were prepared from condensation-type macromonomers. Dicarboxyl-terminated poly(perfluoroalkylethyl acrylate) was prepared by radical chain transfer polymerization and copolycondensed with diamines and dicarboxylic acids in the presence of triphenylphosphine and pyridine. Nylon-6 films containing various amounts of the resulting graft copolyamides were obtained by heat pressing. Only 5 wt % of graft copolymers were sufficient to make nylon-6 surfaces water repellent.
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  • 91
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 3031-3042 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-Phenylethyl trifluoroacetate (1) does not react directly with styrene but it is readily incorporated into polymer chains in the presence of an excess of trifluoroacetic acid. The proportion of the nondeuterated 1-phenylethyl end groups in the polymerization of deuterated styrene coinitiated with the acid was much higher than the proportion of the end groups formed by direct incorporation of the acidic protons ([CH3—CHPh—CD2—CDPh— …] 〉 [HCD2—CDPh—CH2—CDPh— …]). The racemization of the optically active ester-(pseudo-first order rate constant at [HA]0 = 0.79 mol/L at 20°C equals kR = 1.7 × 10-4 S-1) is more rapid than the incorporation of the ester into polymer chains (kE = 1.5 × 10-4 mol-1 Ls-1, [M]0 〈 0.4 mol L-1, i.e., kR 〉 kE · [M]). These results and the complete loss of the optical activity in the final polymer indicate that the ester is activated by the acid but it is incorporated into polymer chain via ionic intermediates.
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  • 92
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 3043-3069 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Block copolymers of poly(N-isovaleryl ethyleneimine) (PiVEI) and poly(ethylene glycol) (PEG) were synthesized by coupling previously prepared blocks of PEG ditosylate with the dianion of the dihydroxy PiVEI. On the average four blocks coupled together to form the final block polymer. The PiVEI blocks crystallized with the same melting points as in the homopolymer. This restricted the mobility of the PEG blocks and they did not crystallize unless cooled well below room temperature. The mechanical properties of cast films were quite good with a tensile strength of 77 kg/cm2 and an elongation of 120%. The swelling of unoriented and oriented films with water was studied. The unoriented polymer absorbed about its own volume of water, even though PEG comprised only 40% of the total polymer.
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  • 93
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 3089-3102 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ethylene was polymerized by Cp2ZrCl2-methylaluminoxane (MAO) catalysts where a portion of the MAO was replaced with trimethyl aluminum (TMA). At a total Al to Zr ratio of 1070, there is neither appreciable loss of productivity nor change in polymerization profile for TMA/MAO ≤ 10. The productivity is reduced only by two- to three-fold for TMA/MAO ≤ 100 accompanied by a 10 min induction period. Aging of this catalyst did not affect the induction period, but improves its productivity. The kinetic isotope effect for radiolabeling with tritiated methanol is 2.0. About 40% of the Zr is active for the catalyst with {99 [TMA] + 1[MAO]} to Zr ratio of 100. The rate constants for propagation and chain transfer were obtained. The mechanisms for the mixed TMA and MAO cocatalyst system are discussed. The results of this work have important practical significance. MAO is a hazardous material to synthesize and only in low yields. The replacement of 〉 90% of MAO with TMA represents a substantial saving since as much as 0.1M of the former is commonly used for a polymerization.
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  • 94
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1307-1314 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title polymers were synthesized and the oxygen permeation behavior through the polymer films were studied. The oligodimethylsilane-substituted polystyrenes showed a little low Po2 compared with the oligodimethylsiloxane-substituted polystyrenes. The important role of trimethylsiloxyl group in permeation was suggested.
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  • 95
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1315-1322 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The pyrolyses of homologous poly(alkyl acrylate)s is reported with identification of the major pyrolyses products. A mechanism involving random homolytic scission of the chain followed by a series of intermolecular and intramolecular transfer reactions has been proposed for poly(methyl acrylate) by Cameron and Kane and further developed by Haken, Ho, Houghton, and Gunawan. This mechanism is demonstrated to be generally applicable to the poly(n-alkyl acrylate)s. Reaction mechanisms are postulated for the various products produced and ion fragmentation mechanisms for the mass spectra produced are shown.
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  • 96
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1335-1341 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Schiff base (SB) monomers of vinylbenzaldehyde with functional amines were prepared. Copolymers of SB monomers with N-vinyl-2-pyrrolidone soluble in aqueous solutions were obtained in most cases. However, p-aminobenzenesulfonamide monomer resulted in gel formation. Thus, the reaction of vinylbenzaldehyde copolymer with the sulfonamide was used instead of the copolymerization. The hydrolytic behaviors of SB monomers and copolymers to liberate respective amines were structure dependent and, for most copolymers, the rates were lower than those of the corresponding monomers.
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  • 97
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1323-1334 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the reaction between atactic polypropylene (APP) and oxygen in bulk at temperatures ranging from 170 to 210°C and oxygen partial pressures from 160 to 760 torr have been studied by thermal differential analysis. The reaction takes place in two successive steps, both giving hydroperoxide groups as product. Partial reaction orders with respect to APP and oxygen for the first step, which corresponds to the uncatalyzed attack of a C—H tertiary bond to give a hydroperoxide, are one and two, respectively. In the second step, interpreted as another attack on a tertiary C—H by oxygen, catalyzed by a neighboring hydroperoxide group, reaction orders are one and one-half for APP and oxygen, respectively. Activation parameters have been determined and a reaction sequence is proposed. Hydroperoxidated APP subsequently decomposes via a zero-order process giving methylketone groups as its main product. An interpretation of this process is also given.
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  • 98
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 3189-3198 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α-Methoxyphenylmethylium hexachloroantimonate was prepared from α-methoxybenzyl chloride and antimony pentachloride at 0°C and isolated for the first time, and its visible and 1H-NMR spectra were measured. This salt was used as a novel initiator for the polymerization of propylene oxide (PO) in the temperature range -20 to 30°C with dichloromethane as solvent. PO polymerized spontaneously but a limit yield was observed. The microstructure of PO polymer is amorphous by 13C-NMR. The PO polymerization is thought to proceed in the conventional cationic mechanism on the basis of the polymerization behavior and the analyses of both the polymer structure and end groups attached to the PO polymer.
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  • 99
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1377-1391 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effects of carbon blacks, chopped carbon fibers, and crushed carbon fibers on the crosslinking chemistry of a diglycidyl epoxy resin/m-phenylenediamine system were examined by infrared (IR) spectroscopy and differential scanning calorimetry (DSC). The carbon and graphite surfaces were given oxidizing and reducing treatment to simulate the surface treatment of carbon fibers used in the manufacture of composites. The oxidized carbon surfaces initially accelerated epoxy-amine reactions but inhibited the later stages of the reaction such that the final extent of cure was reduced. The oxidized carbons also preferentially adsorbed the amine curing agent, resulting in a stoichiometric imbalance at the interface.
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  • 100
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    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1361-1376 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cyanoacetamides are a novel class of curing agents for epoxy resins. Since reaction products of epoxy compounds with cyanoacetamides have not yet been described, we investigated the reaction of phenyl-glycidylether (PGE) and N-isobutylcyanoacetamide (NICA) under the conditions of the epoxy cure (120-150°C). Twenty-two fractions of the reaction product have been separated by preparative TLC and characterized by FD and MS mass spectroscopy. The structures of 10 reaction product have been elucidated by MS, NMR, and IR techniques. They belong to the classes of cyclic urethanes, spiro-dilactones, cyclo-oxa-1-hepten-4-one-2, pyrimidones, aminocrotononitrile, and tertiary amine. This complex model reaction mixture does not enable us to propose a curing mechanism. However practical cure of Bisphenol A diglycidylether (BADGE) yields clear and tough solids with a glass transition temperature up to 200°C, good mechanical strength, and high adhesion to metal surface. Cyanoacetamides are latent hardeners requiring a curing initiator. Since N-4-chlorophenyl-N′-dimethylurea is a latent initiator, liquid, homogeneous, storage stable “one shot” systems can be formulated which harden quickly above 120°C. Heat aging properties of cured specimens are reported. A series of novel liquid, resinous, and crystalline cyanoacetamides and their potential as curing agent are described.
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