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Abstract  

The thermal analysis methods (TG, DTG and DTA) were used for the investigation of the thermal degradation of some recent manufactured tanned leathers, leathers that are supports of cultural or historical objects (leather from book covers (XVII-XIX centuries); leather from an Austrian belt (Franz Joseph period), Cordoba leather (XVII century), lining leathers), recent and patrimonial parchments and recent extracted collagen (sorts of collagen obtained from bovine leather at different pH-values, bovine collagen with different hydration degree). At progressive heating, all investigated materials exhibit two main successive processes, associated with the dehydration and thermo-oxidative degradation. Each analyzed material has a characteristic thermal analysis curve (TG, DTG and DTA) that can be considered a material 'fingerprint'. This result suggests the use of the thermal analysis methods to identify of leathers from which the patrimonial objects are manufactured. The rate of thermo-oxidation of recent manufactured tanned leathers is substantially higher than the rate of the same process corresponding to naturally aged leathers that exhibit values of the thermo-oxidation rate appropriate to those obtained for parchments and collagens. The rate of thermo-oxidation of leather can thus be used as a criterion to distinguish between recent manufactured leather and patrimonial one.

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Abstract  

Vinylidene chloride polymers containing comonomer units capable of consuming evolved hydrogen chloride to expose good radical-scavenging sites might be expected to display greater thermal stability than similar polymers containing simple alkyl acrylates as comonomer. Incorporation of a comonomer containing the phenyl t-butyl carbonate moiety into a vinylidene chloride polymer has the potential to afford a polymer with pendant groups which might interact with hydrogen chloride to expose phenolic groups. Copolymers of vinylidene chloride with [4-(t-butoxycarbonyloxy)phenyl]methyl acrylate have been prepared, characterized, and subjected to thermal degradation. The degradation has been characterized by thermal and spectroscopic techniques. The degradation of vinylidene chloride/[4-(t-butoxycarbonyloxy)phenyl]methyl acrylate copolymers is much more facile than the same process for similar copolymers containing either [4-(isobutoxycarbonyloxy)phenyl]methyl acrylate or methyl acrylate, a simple alkyl acrylate, as comonomer. During copolymer degradation, [4-(t-butoxycarbonyloxy) phenylmethyl acrylate units are apparently converted to acrylic acid units by extensive fragmentation of the sidechain. Thus, the phenyl t-butyl carbonate moiety does function as a labile acid-sensitive pendant group but its decomposition in this instance leads to the generation of a phenoxybenzyl carboxylate capable of further fragmentation.

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Abstract  

Complexes of cell–THPC–urea–ADP with transition metal ion Co2+ and lanthanide metal ions such as La3+, Ce4+, Nd3+ and Sm3+ have been prepared. The thermal behavior and smoke suspension of the samples are determined by TG, DTA, DTG and cone calorimetry. The activation energies for the second stage of thermal degradation have been obtained by following Broido equation. Experimental data show that for the complexes of cell–THPC–urea–ADP with the metal ions, the activation energies and thermal decomposition temperatures are higher than those of cell–THPC–urea–ADP, which shows these metal ions can increase the thermal stability of cell–THPC–urea–ADP. Moreover, these lanthanide metal ions can more increase thermal stability of samples than do the transition metal ion Co2+. The cone calorimetry data indicate that the lanthanide metal ions, similar to transition metal Co2+, greatly decrease the smoke, CO and CO2 generation of cell–THPC–urea–ADP, which can be used as smoke suppressants.

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Abstract  

Dynamic mechanical and thermal properties of poly(ester urethanes) (PEU) cross-linked with styrene have been studied. The investigated polyurethanes were obtained from 4,4′-diphenylmethane diisocyanate and unsaturated oligo(alkyleneester)diol based on cis-2-butene-1,4-diol. The conducted analyses dealt with the correlation between the chemical structure of poly(ester urethanes) and their ability to phase separate as well as their thermal stability. The products of PEU thermal degradation were characterized using infrared spectroscopy.

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Journal of Thermal Analysis and Calorimetry
Authors:
K. L. G. V. Araújo
,
P. S. Epaminondas
,
M. C. D. Silva
,
A. E. A. de Lima
,
R. Rosenhaim
,
A. S. Maia
,
L. E. B. Soledade
,
A. L. Souza
,
I. M. G. Santos
,
A. G. Souza
, and
N. Queiroz

oil subjected to thermal degradation, using thermogravimetry (TG), pressurized differential scanning calorimetry (PDSC), physicochemical methods, UV–vis spectroscopy and chromatography. Experimental The crude fish oil from

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Abstract  

The thermal degradation behavior of P. halepensis needles treated with two ammonium-polyphosphate-based commercial retardants was studied using thermal analysis (DTG) under nitrogen atmosphere. Moreover, for the same experimental material, the heat of combustion of the volatiles was estimated based on the difference between the heat of combustion of the fuel and the heat contribution of the charred residue left after pyrolysis. The heat of combustion of the volatiles was exponentially related to the retardant concentration of the samples. In the range of retardant concentrations from 10 to 20% w/w the mean reduction percentage of the heat of combustion of the volatiles, with respect to untreated samples, was 18%.

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Abstract  

Hyperbranched epoxy resin (HTDE) has relatively low viscosity and high molecular mass and holds great promise as a functional additive for enhancing the strength and toughness of thermosetting resins. In this work, the curing and thermal degradation kinetics of HTDE/diglycidyl ether of bisphenol-A epoxy (DGEBA) hybrid resin were studied in detail using differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) techniques by Coats–Redfern model. The effect of molecular mass or generation and content of HTME on the activation energy, reaction order, and curing time were discussed; the results indicated that HTDE could accelerate the curing speed and reduce the activation energy and reaction order of the curing reaction.

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Plus UV-Vis (Analytik Jena) instrument and expressed as mg cyanidin-3-O-glucoside/100 g DW. 1.4 Thermal degradation kinetics The thermal stability was evaluated during heating the crude extract in citrate buffer pH 3.5 at 50 °C and 80 °C. Plotting lnC

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Journal of Thermal Analysis and Calorimetry
Authors:
Valentina Uivarosi
,
Mihaela Badea
,
Rodica Olar
,
Dana Marinescu
,
Teodor Octavian Nicolescu
, and
George Mihai Nitulescu

Cl 2 ]Cl·4H 2 O ( b ) Thermal behavior of complexes An analysis of the thermal degradation behavior of the ruthenium–fluoroquinolone complexes was the primary focus of the study

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Abstract  

The thermal behaviour of ultra-high molecular weight polyethylene (UHMWPE) of different molecular weights was examined by thermal analysis methods. The melting temperatureT m and the heat of melting δH were measured by the DSC method. The thermooxidative degradation process was investigated by using a MOM Q-1500 D derivatograph at various heating rates in air atmosphere. The initial decomposition temperatureT i was determined from the TG curves, and other characteristic temperatures of decomposition were calculated. It was found thatT m and δH are higher for UHMWPE than those for HDPE, i.e. 146‡C and 195 J g−1 for UHMWPE as compared with 133‡C and 166 J g−1 for HDPE. The thermal behaviour of the investigated UHMWPE samples is not significantly influenced by molecular weight.

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