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  • 1
    Electronic Resource
    Electronic Resource
    Antioxidants and stabilizers (1983)
    Springer
    Polymer bulletin 9 (1983), S. 121-124 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The efficiency of polyolefine melt stabilizer 2, 2′-thiobis-(4,6-di-tert.butylphenol) (I) as a hydroperoxide decomposing antioxidant was studied under model conditions.tert.Butylhydroperoxide was used to simulate the reaction with polypropylene hydroperoxide. The reaction was performed at 85°C in chlorobenzene solution. Decomposition of tert.butylhydroperoxide by I and formation of the sulphoxide II and the sulphone III from sulphide I were followed quantitatively. Formation of small amounts of effective peroxidolytic species from II or III, responsible for acceleration of hydroperoxide decomposition was considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00275578
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  • 2
    Electronic Resource
    Electronic Resource
    Exploitation of the current knowledge of antioxidant mechanisms for efficient polymer stabilizationPresented as an invited keynote lecture at the 33rd IUPAC Congress, Budapest, 17-22 August 1991 in the polymer section organized by Professor F. Tudos. (1992)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 3 (1992), S. 443-455 
    Details
    ISSN: 1042-7147
    Keywords: Antioxidant mechanisms ; Photo-antioxidants ; Polymer durability testing ; Polymer stabilization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: New mechanistic knowledge of antioxidant and photoantioxidant mechanisms is interpreted to meet the requirements of processing stability and durability of commercial plastics, rubbers and coatings in hostile environments. Factors reducing stabilizer activity and some ecological concerns dealing with polymer stabilization are included.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1992.220030805
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  • 3
    Electronic Resource
    Electronic Resource
    Antioxidantien und Stabilisatoren XXVIII. Gelchromatographie nichtflüchtiger phenolischer antioxidantien zur stabilisierung von polymerenHerrn Professor Dr. W. KERN zum 65. Geburtstag gewidmet (1971)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 15 (1971), S. 137-146 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: High resolution gel chromatography was applied to the analysis of phenolic antioxidants mixtures formed by an alkylation of 4,4'-isopropylidenebisphenol and used for the stabilisation of polyolefins and rubbers. The calibration by pure model substances provided values of relative zone rates on S-GEL-832 for a series of tert-butyl and tert-octyl derivatives of phenol and 4,4'-isopropylidenebisphenol. The chromatograms show in some cases a separation of isomers differing in size of their molecules in solution.
    Notes: Für die Analyse der bei der Alkylierung von 4,4′-Isopropylidenbisphenol anfallenden und zur Stabilisierung von Polyolefinen und Kautschuk bestimniten phenolischen Antioxidans-Gemischen wurde die Gelchromatographie mit großem Auflösungsvermögen herangezogen. Durch Eichung mit reinen Modellsubstanzen wurden die relativen Zonengeschwindigkeiten einer Reihe tertiärer butylierter und octylierter Phenole und 4,4'-Isopropylidenbisphenole an Gel S-GEL-832 bestimmt. In einigen Fällen erwiesen die Chromatogramme die Trennung der sich durch das Molekülvolumen in Lösung unterscheidenden isomeren Verbindungen.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1971.050150111
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  • 4
    Electronic Resource
    Electronic Resource
    Antioxidants and stabilizers. IL. 1,3,5-trimethyl-2,4,6-tris (1-tert-butylperoxy-3,5-ditert-butylcyclohexa-2,5-diene-4-onylmethyl)benzene: Formation, properties and effect on the oxidation of tetralin and isotactic polypropylene (1974)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 38 (1974), S. 191-205 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurde die Umwandlung des Antioxidans 1,3,5-Trimethyl-2,4,6-tris(3,5-ditert-butyl-4-hydroxybenzyl)benzol(I) während der Reaktion mit tert-Butylhydroperxid in Anwesenheit von Kobalt(II)-acetylacetonat verfolgt. In tert-butlakoholischer Lösung entsteht das Produkt II durch partielle Oxidation, in Benzol dagegen ist das Cyclohexadienon III das Hauptprodukt. Die Strukturen der beiden Osxidationsprodukte II und III wurden bestimmt und ihre thermischen und photochemischen Eigenschaften untersucht. Die antioxidative Aktivität des Trisphenols I geht durch seine stufenweise oxidative Umwandlung verloren. Die Oxidationsprodukte II und III haben bei der Temperatur ihres Entstehens keinen negativen Einfluß auf den Verlauf der thermischen Oxidation. Nach Erwärmen des organischen Substrats in die Nähe ihrer Zersetzungstemperatur wirken sie dagegen initiierend. Sie unterliegen schon bei Zimmertemperatur einer photochemischen Umwandlung und verfäben das Polymere.
    Notes: The transformation of the antioxidant 1,3,5-trimethyl-2,4,6-tris(3,5-ditert-butyl-4-hydroxybenzyl)benzene (I) by the oxidation with tert-butyl hydroperoxide in the presence of Co(II)acetylacetonate was investigated. The reaction in tert-butyl alcohol gives rise to product II of partial oxidation, while in benzene cyclohexadienone III is formed. The oxidation products were defined, and their thermal properties and behaviour in light were determined. The oxidative transformation of trisphenol I leads to a loss of its antioxidative activity. The oxidation products II and III at the temperature of their formation do not exhibit an unfavourable effect on the process of thermal oxidation. However, after heating of the hydrocarbon substrate containing them to a temperature close to their decomposition point they act as initiators. They undergo photochemical transformation already at room temperature and give colour to the polymer.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1974.050380116
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  • 5
    Electronic Resource
    Electronic Resource
    Antioxidants and stabilizers. L. Transformation of the 1,3,5-tris(4-hydroxy-3,5-di-tert-butylbenzyl)cyanuric acid into alkylperoxycyclohexadienones, their properties and effects on the oxidation of tetralin and polypropylenePart IL: See reference3. (1974)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 39 (1974), S. 107-118 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Umwandlung von 1,3,5-Tris(4-hydroxy-3,5-di-tert-butylbenzyl)cyanursäure (I), die als Antioxidans für Polyolefine dient, wurde während der Reaktion mit tert-Butylperoxyl untersucht. Zwei Oxidationsprodukte II und III entstehen in tert-Butylalkohol; die Umwandlung läuft schneller in Benzol, und als Produkt entsteht hier nur das Cyclohexadienon III. Es wurde die Struktur der Oxidationsprodukte bestätigt, die thermischen Eigenschaften mittels DTA gemessen und der Einfluß auf den Oxidationsverlauf von Tetralin und Polypropylen verfolgt. Während der oxidativen Umwandlung verliert das Trisphenol I seine antioxidativen Eigenschaften. Der Unterschied in der Aktivität von Trisphenol I und von einem anderen wichtigen phenolischen Antioxidans, 1,3,5-Trimethyl-2,4,6-tris(4-hydroxy-3,5-di-tert-butylbenzyl)benzol (IV), unter den Bedingungen der inhibierten Oxydation von Polyolefinen wird diskutiert.
    Notes: The transformation of 1,3,5-tris(4-hydroxy-3,5-di-tert-butylbenzyl)cyanuric acid (I), designed as an antioxidant for polyolefins, during its reaction with tert-butylperoxyls was studied. In tert-butyl alcohol two oxidation products, II and III, are formed, while in benzene the reaction proceeds faster with formation of cyclohexadienone III. The structures of the oxidation products were confirmed, their thermal properties were measured (by DTA) and the effect on the oxidation of tetralin and isotactic polypropylene was determined. The oxidative transformation makes trisphenol I lose its antioxidative property. The different behaviour of trisphenol I and another important phenolic antioxidant, namely, 1,3,5-trimethyl-2,4,6-tris(4-hydroxy-3,5-di-tert-butylbenzyl)benzene (IV) under the conditions of inhibited oxidation of polyolefins is discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1974.050390109
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  • 6
    Electronic Resource
    Electronic Resource
    Antioxidants and stabilizers LXVII.Part LXVI, Angew. Makromol. Chem. 65 (1977) 197. Transformation of 4,4′-thiobis(2-methyl-6-tert-butylphenol) under conditions of inhibited autoxidationPresented at 5th International Rubber Symposium, Gottwaldov, September 1-5, 1975. (1978)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 66 (1978), S. 95-104 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der Mechanismus der antioxidativen Wirkung von Thiobisphenolen während der Inhibierung der durch Hydroperoxidzersetzung initiierten Autoxidation von Polyolefinen wurde durch eine Modellreaktion von 4,4-Thiobis(2-methyl-6-tert-butylphenol) (I) mit tert-Butylhydroperoxid in Anwesenheit von Kobalt(II)-acetylacetonat untersucht. Die aus der Reaktionsmischung isolierten Produkte bestätigen, daß Thiobisphenole als Phenole die Wachstumsreaktion in der inhibierten Autoxidation unterbrechen und als Sulfide die Hydroperoxide zu nichtradikalischen Produkten zersetzen.
    Notes: The mechanism of the antioxidative effect of thiobisphenols in the inhibition of autoxidation of polyolefins initiated by the decomposition of hydroperoxides was studied by means of a model reaction of 4,4′-thiobis(2-methyl-6-tert-butylphenol) (I) with tert-butylhydroperoxide in the presence CO(II)acetyl acetonate. Products isolated from the reaction mixture prove that in the inhibition of autoxidation, thiobisphenols break as phenols the propagation chains of radical autoxidation, while they decompose as sulphides the hydroperoxides into nonradical products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1978.050660108
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  • 7
    Electronic Resource
    Electronic Resource
    Antioxidants and stabilizers. LII. Sensitized photooxidation of 2,6-di-tert-butyl-4-methylphenolPart LI. Eur. Polym. J., in press. (1974)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 39 (1974), S. 189-202 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die mittels Methylenblau sensibilisierte Photooxidation von 2,6-Di-tert-butyl-4-methylphenol (IV) in Methanol wurde im Zusammenhang mit dem Studium der Umwandlungen von Stabilisatoren während der Alterung von Polymeren studiert. Während der Reaktion in verdünnter Lösung wurde das Phenol (IV) mit Singulett-Sauerstoff zu 2,6-Di-tert-butyl-4-methyl-4-hydroperoxy-2,5-cyclohexadien-1-on (V) oxidiert. In konzentrierter Lösung wurde das Phenol (IV) durch angeregten Sensibilisator angegriffen: dadurch entstand zuerst das entsprechende Aryloxyl, dessen weitere Umwandlung zu 2,6-Di-tert-butyl-4-methoxymethylphenol (VI) führte. Das Phenol (VI) reagierte weit langsamer, aber analog dem Phenol (IV), d. h. durch Reaktion mit Singulett-Sauerstoff entstand 2,6-Di-tert-butyl-4-methoxymethyl-4-hydroperoxy-2,5-cyclohexadien-1-on (VIII). Ebenso entstand ein Aryloxyl durch Reaktion mit dem angeregten Sensibilisator; weitere Umwandlungen führten zum 3,5-Di-tert-butyl-4-hydroxybenzaldehyd (X). Die Verbindungen (VIII) und (X) reagierten weiter zum 2,6-Di-tert-butyl-1,4-benzochinon (IX).
    Notes: In connection with a complex investigation of the transformations of stabilizers during the ageing of polymers, the photooxidation of 2,6-di-tert-butyl-4-methylphenol (IV) sensitized with methylene blue in methanol was investigated. If the reaction takes place in a dilute solution, phenol(IV) is oxidized with singlet oxygen forming 2,6-di-tert-butyl-4-methyl-4-hydroperoxy-2,5-cyclohexadiene-1-one (V). In a concentrated solution phenol (IV) is attacked by an excited sensitizer which gives rise to a corresponding aryloxy radical; transformations of the latter yield 2,6-di-tert-butyl-4-methoxymethylphenol (VI). The further reaction of phenol (IV) is slower, but similar to phenol (IV): by a reaction with singlet oxygen 2,6-di-tert-butyl-4-methoxymethyl-4-hydroperoxy-2,5-cyclohexadienel-one (VIII) is formed, while a reaction with the excited sensitizer again gives rise to the corresponding aryloxyl. Transformations of the latter produce 3,5-di-tert-butyl-4-hydroxybenzaldehyde (X). Under oxidizing conditions the compounds (VIII) and (X) undergo further transformation to yield 2,6-di-tert-butyl-1,4-benzoquinone (IX).
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1974.050390116
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  • 8
    Electronic Resource
    Electronic Resource
    Macromolecular stabilizers for polymersPaper presented at the 18th Colloquium of Danubian Countries for “Natural and artificial ageing of plastics” in Villach, Austria, June 24-26, 1987 (1988)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 158 (1988), S. 221-231 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Inherent chemical activity, physical persistence and good compatibility are factors determining the efficiency of a stabilizer observed during the degradation of amorphous and crystalline synthetic polymers. Synthesis of macromolecular stabilizers is one of the ways used to solve the problem of physical persistency of stabilizers under severe aggressive environmental attacks on polymers. General types of macromolecular stabilizers, routes to their synthesis and characteristic examples of macromolecular antioxidants, UV absorbers, hindered amine light stabilizers, flame retarders and biostabilizers, as well as of polyfunctional systems are given. Problems connected with the use of macromolecular stabilizers are mentioned.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1988.051580112
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  • 9
    Electronic Resource
    Electronic Resource
    Antioxidants and stabilizers, 102Part 101: Chem. & Ind. (London), in press.. Transformation of 2,6-dialkylphenols under gamma-irradiation in benzene and isooctane solutionsPresented in part at the 25th IUPAC Microsymposium on Processing and Long-Term Stabilities of Hydrocarbon Polymers in Prague, July 1983, paper P52. (1986)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 141 (1986), S. 161-172 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der Mechanismus der Teilnahme von phenolischen Antioxidantien in γ-initiierten Prozessen unter Modellbedingungen wurde simuliert. γ-Bestrahlung von Lösungen des 2,6-Dialkylphenols (I) in Benzol und Isooktan im Vakuum führt zur Modifizierung des Antioxidants. Diese beinhaltet C—C- und C—O-Kupplungsreaktionen von Radikalen, die aus I entstanden sind, und ihre Kombination mit den aus dem Substrat RH generierten Radikalen R°. Die C—C-Kupplung wird bei Anwesenheit von niedrigeren Konzentrationen von I in RH unterdrückt. Als Folge davon nehmen sowohl die Ausbeuten der korrespondierenden tetraalkylierten Biphenyldiole V als auch die nachträgliche Bildung der Diphenochinone VI ab. 2,4,6-Trialkylphenol III wurde als Hauptprodukt im aliphatischen RH (Isooktan) gebildet.
    Notes: The mechanism of phenolic antioxidants participation in γ-radiation initiated processes in polyolefins has been simulated under model conditions. The γ-irradiation of benzene and isooctane solutions of 2,6-dialkylphenols (I) in vacuum results in an antioxidant transformation. The latter involves C—C, and presumably also C—O couplings of radicals formed primarily from I and their combination with R° radicals generated from hydrocarbon substrate (RH). The C—C coupling is suppressed at a lower concentration of I in RH. As a result, both the yield of the respective tetralkylated biphenyldiol V and the consecutive formation of diphenoquinone VI drop. 2,4,6-Trialkylphenol III is the majority product formed in the aliphatic RH (isooctane).
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1986.051410116
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  • 10
    Electronic Resource
    Electronic Resource
    Transformation products of antioxidants: The role in stabilization mechanismsPaper presented at the 18th Colloquium of Danubian Countries for “Natural and artificial ageing of plastics” in Villach, Austria, June 24-26, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 158 (1988), S. 209-219 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Antioxidants acting in polymers by chain-breaking and hydroperoxide decomposing mechanisms are chemically transformed during the stabilization process as a consequence of trapping radicals R•, RO• or RO•2 and/or reactivity with hydroperoxides. New chemical compounds with typical structures characteristic of the starting stabilizer are formed stepwise in the polymer mass. Most of these transformation products participate actively in consecutive steps of polymer degradation. Finally observed phenomena depend on the concentration of individual transformation products. Generally, autocooperative effects with starting stabilizers take place. Important data regarding properties of transformation products have been summarized.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1988.051580111
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