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Showing 1 to 20 of 61 for “"Oxidative degradation"”.
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Thermal and oxidative degradation of an aromatic polyamide
… of the cobalt is increased. Furthermore, T.G.A. oxidative degradation studies, conducted at isothermal temperatures in the solid state, show decreases in the activation energies associated with fibre oxidation with increased cobalt concentrations, implying the cobalt is a catalyst for oxidation. …
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Photo-oxidative degradation and stabilization of acrylonitrile-butadiene-styrene (ABS)
… such as ABS, is their susceptibility to photo-oxidative degradation when exposed to ultraviolet (UV) radiation in the presence of oxygen. This work is dedicated to the study of the influence of weathering under natural and accelerated conditions on chemical structure and properties of ABS, …
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Studies on the oxidative degradation of fluphenazine decanoate in oily solution
… was undertaken so that the formation of these degradation products in oily solution, could be accurately determined. By this means the rate of oxidation of fluphenazine decanoate by various hydroperoxides was determined. Only in the case of the C-IB unsaturated fatty esters did the overall …
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Characterisation of waxy gas-condensates by high temperature capillary gas chromatography and oxidative degradation
… the most resistant petroleum components to biodegradation. The current study reports the development of reproducible quantitative high temperature capillary gas chromatography (HTCGC) methods for studying both these aspects of the chemistry of HMW hydrocarbons. In addition those hydrocarbons …
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A study of the hydrolytic and oxidative degradation of some chlorine derivatives of starch
Call number: LD2668 .T4 1952 S75
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A study of the hydrolytic and oxidative degradation of some chlorine derivatives of starch
Call number: LD2668 .T4 1952 S75
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Investigation of the oxidative degradation mechanisms and melt stabilisation of a new generation metallocene polytehylene
… (m-LLDPE), in order to establish the thermal oxidative degradation mechanism, and secondly, to examine the role of selected commercial stabilisers on the melt stability of the polymers. The unstabilised m-LLDPE polymer was extruded (pass I) using a twin screw extruder, at different …
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Desenvolvimento de método indicativo de estabilidade para detecção de produtos de degradação da associação de zidovudina e lamivudina (300 + 150 mg) em matéria-prima e comprimidos.
… . In order to evaluate the stability of forced degradation test in which the product is subjected to studies provide evidence on how the quality can be varied over time are performed. The method indicative of stability must accurately measure changes in the concentration of active ingredients, …
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Organisch-geochemische Untersuchungen der Oberflächengewässer aus dem Einzugsgebiet der Sielacht Esens (Ostfriesland)
… The obtained results are compared with the oxidative degradation by cupric oxide (CuO). Ratios of lignin-derived compounds are indicative of the extent of oxidative degradation and suggest a highly degraded state of the lignin compounds in all samples. Samples from different locations show …
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Study of the oxidative degradation of 2,2,3,4,5-pentaphenyl-3- cyclopentenone by various oxidants ; and, [1,5]-sigmatropic phenyl rearrangements in 2- and/or 5-(p- or m-substituted phenyl)-1,3,4-triphenyl-2,4- cyclopentadien-1-ols: electronic effects at the migration terminus
… transition state is proposed. In addition, the oxidative degradation of 2,2,3,4,5-pentaphenyl-3-cyclopenten-l-one by various oxidants was investigated. This substrate was found to be inert to all the reagents examined, with the exception of diacetyl chromate. The action of this oxidant upon the …
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Oxidation and stabilisation chemistry of metallocene-based polyolefins during melt processing
… of this work were, firstly, to investigate the oxidative degradation mechanisms of m-LLDPE polymers having different comonomer (I-octene) content during melt processing. Secondly, to examine the effectiveness of some commercial antioxidants on the stabilisation of m-LLDPE melt. A …
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Part1. Relative antioxidant efficiency of synthetic and natural compounds; Part 2. Synthesis, characterization of cysteine oligopeptides and assessment of their antioxidant activity
… - mass spectrometry determinations of oxidative degradation products...The second part of the research involved enzymatic synthesis and liquid chromatographic - mass spectrometric (LC-MS) characterization of cysteine containing hydrophobic oligopeptides. Two types of oligopeptides …
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Plastic Waste-Derived CO2 Sorbents and Methods for Enhanced Selectivity and Stability
… stability especially in the presence of oxygen. Oxidative degradation pathways of PEI lead to imine formation and ammonia evolution; these end-products greatly reduce the sorbent’s CO2 uptake capacity. While strategies to reduce oxidative degradation exist through polymer modification, we show …
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Finite Element Analysis to Investigate Lipid Absorption in UHMWPE Under Mechanical Loading
… crosslinking and post-irradiation stabilization, oxidative degradation remains a limitation, contributing to long-term implant failure. Recent studies have shown that in vivo oxidative degradation still occurs, suggesting alternative degradation pathways. One involves the diffusion of lipid …
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The Chemical Durability of Elastomeric Bituminous Geomembranes (BGMS) in Different Geoenvironmental Applications at Elevated Temperatures
… to elevated temperatures resulted in the thermo-oxidative degradation of the bituminous coat that increased its rigidity. Concurrently, the BGM exhibited degradation in the reinforcement layer resulting in the loss of its mechanical properties. The rate of degradation in the BGM components is …
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Degradation Product Analysis of Bismaleimide Composite
This study evaluates the thermal and oxidative stabilities of a bismaleimide (BMI) polymer composite reinforced with an intermediate modulus graphite fiber, Cytec®5260/IM7. The composite is aged in helium, nitrogen, and air at elevated temperatures up to 600°C. Its weight change is followed …
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Alkynylated acenothiadiazoles and N-heteroacenes: synthesis, functionalization, and study of the optical properties for optoelectronic and sensory materials
… of the pyrazine subunit both inhibits oxidative degradation at sensitive position in the molecules. Additionally the trialkylsilylethynyl group aides in directing the packing motif as well as vastly increases the solubility over unsubstituted analogues. A requisite precursor in the …
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Chemical and physical stability of spray-dried and glass encapsulated spray-dried flavors stored below their glass transition temperatures
… flavor loss, such as volatile permeation and/or oxidative degradation, and 4) provide recommendations for shelf-life extension of MET flavors. One benzaldehyde SD flavor and two MET materials, isomalt (ISO) and evaporated cane juice (ECJ), were used as model systems. Samples were packaged in …
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