共查询到20条相似文献,搜索用时 15 毫秒
1.
G. Della Gatta E. Badea R. Ceccarelli T. Usacheva A. Maši? S. Coluccia 《Journal of Thermal Analysis and Calorimetry》2005,82(3):637-649
Summary Environmental impact on parchment was investigated by differential scanning calorimetry (DSC) and scanning electron microscopy
(SEM). Parchments subjected to accelerated ageing and old parchments were compared to evaluate quality and extent of deterioration.
Stability of fibrillar collagen within parchment was determined from the changes in thermodynamic parameters associated with
thermal denaturation. Parchment surface was characterised, and specific morphological criteria were selected for damage assessment.
The thermodynamic and morphological changes of collagen induced by deterioration are discussed, and their correlations are
proposed as a means of ranking damage in old parchments.</o:p> 相似文献
2.
Thermal analysis on parchments I: DSC and TGA combined approach for heat damage assessment 总被引:1,自引:0,他引:1
Ancient, new and artificially aged parchments were investigated with both differential scanning calorimetry (DSC) and thermogravimetry (TGA). Criteria to define a quantitative ranking of the damage experienced by the bulk collagen of historical parchments were assessed. A damage-related correlation was found between the collagen denaturation temperature and the moisture content of the parchment. Qualitative rules for the evaluation of the damage at the nano-and mesoscopic level were achieved on the basis of peculiarities of the shape and width of the DSC signals and confirmed by small angle X-ray scattering patterns. 相似文献
3.
To reveal the fire injuring of parchment, the changes in the thermal behaviour of some goat parchments, obtained from skins
originating from different animals, as a result of thermal aging were determined by thermal analysis methods (DSC; simultaneous
TG/DTG, DSC; micro hot table (MHT)). Thermal aging of parchments was revealed to bring about the decrease in shrinkage temperature,
absolute value of enthalpy of denaturation in water and some changes in non-isothermal parameters characteristic for dehydration
process in static air atmosphere.
The results obtained by DSC analysis performed in N2 and O2 flows as well as those obtained by simultaneous TG/DTG, DSC analyses have shown that both softening (melting) process parameters
and parameters of thermo-oxidative processes have not been changed by thermal ageing. The results obtained by thermal analysis
methods were correlated with those obtained by microscopic investigation of parchment samples immersed in water and scanning
electron microscopy (SEM). The application of these microscopic techniques has revealed the morphology changes in the investigated
parchments as a result of thermal degradation. 相似文献
4.
Shashank Vummidi Lakshman Edward L. Dreizin Mirko Schoenitz 《Journal of Thermal Analysis and Calorimetry》2014,116(1):141-149
The scope of this work was the assessment of thermo-oxidative deterioration, hydrothermal stability, and crystalline zone deterioration of some bookbinding leathers from some religious books published in XVIII century stored in Romanian libraries. In this purpose, the following thermal analysis methods were employed: thermogravimetry/derivative thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The thermo-oxidative damage of investigated leathers was characterized by the rate of the first thermo-oxidation process put in evidence in TG/DTG curves recorded in static air atmosphere. The hydrothermal stability was characterized by shrinkage temperature determined by DSC analysis of leathers in water excess. The damage of the crystalline zone of leathers was determined by DSC in nitrogen flow and DMA analyses. The qualitative damage for each leather and each kind of degradation was evaluated using the criteria resulted by thermal analysis of a large number of collagen-based materials (pure collagens, new and old parchments and leathers). The obtained results could be used for finding the best possible methods for preservation and/or restoration of the investigated bookbinding leathers. 相似文献
5.
A non-destructive and non-invasive method for quantitative characterization of parchment deterioration, based on spectral
measurements, is proposed. Deterioration due to both natural aging (ancient parchments) and artificial aging (achieved by
means of controlled UV irradiation and temperature treatment) was investigated. The effect of aging on parchment native fluorescence
was correlated with its deterioration condition. Aging causes fluorescence intensity drop, spectral shift of the main peak,
and an overall change in the fluorescence spectral features. Digital color imaging analysis based on visible reflectance from
the parchment surface was also applied, and the correspondent color components (RGB) were successively correlated with the
state of parchment deterioration/aging. The fluorescence and color imaging data were validated by analysis of historical parchments,
aged between 50 and 2000 years and covering a large variety of states of deterioration. The samples were independently assessed
by traditional microscopy methods. We conclude that the proposed optical method qualifies well as a non-destructive tool for
rapid assessment of the stage of parchment deterioration. 相似文献
6.
Andrei Cucos Petru Budrugeac Sorina Mitrea Carmen Hajdu 《Journal of Thermal Analysis and Calorimetry》2013,111(1):467-473
In order to observe the influence of sodium chloride on the melting temperature of collagen crystalline region in three new parchments, samples were soaked in water (blanks) and NaCl solutions of different concentrations, then removed, dried in air and measured by means of differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The melting temperature of crystalline region of collagen, T m, was determined as the minimum of the endothermal peak in the range 200–250 °C and as the inflection point of the decrease of storage modulus, respectively. There was observed a decrease in melting temperature of the salt-treated parchments compared to the samples soaked in water, sometimes significant (~20 °C) at certain concentrations of NaCl. Simultaneous TG/DTG/DSC thermal analysis (STA) was also applied for the determination of the amount of sodium chloride in salt-treated parchments, by calculating the mass loss due to the vaporization of NaCl, which occurs above 800 °C. By plotting T m determined by DSC and DMA versus the NaCl content of the samples, an apparent minimum is observed. Additional information regarding the structural features was also obtained through X-ray diffraction (XRD) and attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR). XRD data put in evidence the preservation of collagen crystalline region in all salt-treated samples, while FTIR measurements did not showed significant modification of collagen. By removing the sodium chloride from the salt-treated parchments through washing with water, there is a return of the melting temperatures to the values of blank samples, demonstrating the reversibility of this phenomenon. 相似文献
7.
8.
Identification of collagen-based materials that are supports of cultural and historical objects 总被引:1,自引:0,他引:1
Budrugeac P. Miu L. Popescu C. Wortmann F.-J. 《Journal of Thermal Analysis and Calorimetry》2004,77(3):975-985
The TG, DTG, DTA methods were used for investigation of the thermal degradation in static air atmosphere of some collagen-based
materials (some sorts of collagen, recent manufactured parchments and tanned leathers, patrimonial (historical) leathers).
At the progressive heating, all investigated materials exhibit two main successive processes, associated with the dehydration
and thermo-oxidative degradation. The patrimonial leathers were divided in two groups, namely: a group containing the majority
of the analyzed materials, for which the rates of the thermo-oxidation process are substantially lower than those corresponding
to the recent manufactured leathers, and a group for which the rates of thermo-oxidation process are closed to those corresponding
to the recent manufactured leathers. Consequently, if by the thermal analysis in air atmosphere of a leather sample, a value
of the rate of the thermo-oxidation process smaller than that corresponding to the recent manufactured leathers is obtained,
then the analyzed leather is a patrimonial one. The reciprocal statement of this qualitative criterion for distinction between
recent manufactured leather and patrimonial leather is not valid. The DSC analyses of collagen-based materials were performed
in air (DSC(air)) and in water (DSC(water)). The denaturation process takes place at lower temperatures in water than in air.
Unlike recent manufactured leathers and parchments, each patrimonial leather exhibits on DSC(water) plot 2-4 peaks. Consequently,
the number of peaks from DSC(water) curve could be another qualitative criterion for distinction between a recently manufactured
leather and a patrimonial leather.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
Bella Dolgin Valery Bulatov Israel Schechter 《Analytical and bioanalytical chemistry》2009,395(7):2151-2159
A nondestructive method for quantitative parchment characterization and sensitive indication of its deterioration stage was
developed. Synchronous fluorescence (SF) measurements were applied for the first time to parchment samples. The method provides
detailed spectral features, which are useful for parchment characterization. The discrimination of parchment samples into
groups (modern, historical, and artificially aged) was successfully performed. The SF spectra could be resolved into specific
fluorophores, which were related to the parchment condition. The spectral data indicate a continuous change in the collagen-to-gelatin
ratio during the aging process. Depth-resolved synchronous fluorescence spectra were also measured. The data indicate that
parchments possess a layered structure, and the dominant fluorophore in the upper layer is different from those in the lower
layers. Layer-resolved profiling allows for quantifying the contribution of each fluorophore in each given layer. This way,
significant differences between modern, artificially aged, and historical samples can be observed. 相似文献
10.
11.
Odlyha M. Cohen N. S. Foster G. M. Aliev A. Verdonck E. Grandy D. 《Journal of Thermal Analysis and Calorimetry》2003,71(3):939-951
DMA and solid state 13C NMR techniques were used to measure historical parchment samples within the framework of the project (MAP) Micro Analysis
of Parchment (EC contract No. SMT4-96-2101) in collaboration with the School of Conservation in Copenhagen. DMA was used in
both thermal scan and creep modes. Thermal scans provided information on the transitions associated with the collagen polymer.
Microthermal analysis was also used to obtain information on the topography and thermal conductivity of sample areas of 100
μm. Localised heating enabled measurements of softening transitions in the sample. This behaviour is influenced by the chemical
composition of parchment. 13C NMR provided information on the carbon atoms associated with the polypeptide chains of the collagen
in parchment. The behaviour of samples immersed in water and measured in DMA creep mode was used to measure the shrinkage
behaviour of the parchment samples. The different but complementary techniques provided a means for characterising the physicochemical
state of parchment samples.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
C. Popescu P. Budrugeac F.-J. Wortmann L. Miu D.E. Demco M. Baias 《Polymer Degradation and Stability》2008,93(5):976-982
The thermal degradation of collagen-based materials, viz. collagen, recently manufactured parchments and tanned leathers, a heritage parchment and patrimonial (historical) leathers, was investigated by thermal analysis methods. With progressive heating, all these materials exhibit three main successive processes, associated with dehydration, protein denaturation and pyrolysis/oxidation. The analysis of both denaturation and thermo-oxidation revealed significant differences between aged leather, collagen, recently manufactured parchments and tanned leathers in terms of the number of overlapping processes (reflected in the number of peaks recorded at denaturation) and of the oxidative degradation rates, given by the normalised curves of differential thermal gravimetry (DTG). The various observations are proposed as qualitative indices for assessing the age and storage conditions of leather. A three-phase model was used for explaining the results. This consists of crystalline collagen filaments that are embedded in an amorphous matrix with an interface zone between the crystalline and amorphous regions. Solid-state 1H NMR investigations corroborate the thermal analysis results and enhance the understanding of the ageing processes. 相似文献
13.
Elena Badea Lucreţia Miu P. Budrugeac Maria Giurginca A. Mašić Nicoleta Badea G. Della Gatta 《Journal of Thermal Analysis and Calorimetry》2008,91(1):17-27
A comprehensive investigation has been made of a set of 14th to 16th-century parchment bookbindings from the Historical Archives of the City of Turin. Advanced physico-chemical techniques, such as thermal analysis (DSC, TG and DTA), spectroscopy (FTIR and UV-Vis-NIR), scanning electron microscopy (SEM) and unilateral nuclear magnetic resonance (NMR-ProFiler) were employed to assess specific deterioration processes occurring at different levels in the hierarchical structure of parchment. Changes in the measured physical and chemical parameter values of parchment due to interaction with the environment were used to identify possible deterioration pathways. 相似文献
14.
The hyphenated thermal analysis-mass spectrometry
technique (TA-MS) was applied for the investigation of the thermal behavior
of reference and aged parchment samples. The kinetic parameters of the process
were calculated independently from all recorded TA and MS signals. The kinetic
analysis showed the distinct dependence of the activation energy on the reaction
progress. Such behavior is characteristic for the multistage mechanism of
the reaction.
The comparison of the kinetic parameters calculated
from the different signals i.e. TG, DSC, MS for H2O,
NO and CO2, however, indicated that they were differently
dependent on the aging of the sample. For the parchment samples, the aging
almost does not change the kinetics of the decomposition calculated from the
DSC data: the influence of aging seems to be too negligible to be detected
by these techniques. On the other hand, the much more sensitive mass spectrometric
technique applied to the kinetic analysis allowed monitoring of visible changes
in the thermal behavior of the parchment samples due to the aging process.
The influence of aging was especially visible when the MS signals of water
and nitric oxide were applied for the determination of the kinetic parameters.
The applied method of the kinetic analysis allowed also the prediction
of the thermal behaviour of reference and aged parchment samples under isothermal
and modulated temperature conditions. Presented results have confirmed the
usefulness of thermoanalytical methods for investigating behaviour of such
complicated systems as leather or parchment. 相似文献
15.
16.
Dell'Abate M. T. Benedetti A. Sequi P. 《Journal of Thermal Analysis and Calorimetry》2000,61(2):389-396
The possibility to use thermal analysis for a quick characterisation of chemical changes in the organic matter of composted
materials was tested. Nine samples were taken at progressive stages of maturation from the same trench of a fully automated
composting plant. DSC and TG were simultaneously performed in static air conditions on whole ground composts. Progressive
stages in the composting process yielded samples whose DSC traces revealed appreciable modifications in thermal patterns that
agreed well with quantitative data obtained from TG measurements. The ratio between the mass losses associated with the two
main exothermic reactions (R1) showed a good sensitivity in detecting the changes in the level of stabilisation during the
composting process. Thermal methods seem to be a valid comparative method in evaluating the level of bio-transformation of
materials during a composting process.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
17.
F. Cataldo O. Ursini E. Lilla G. Angelini 《Journal of Radioanalytical and Nuclear Chemistry》2008,275(1):125-131
Gelatin, the low molecular weight collagen derivative from porcine skin was transformed into a stable permanent hydrogel by
γ-radiation. A series of samples with 3% gelatin solution in water were irradiated at doses of 12, 25, 50, 100, 150, 200 kGy
at room temperature in the absence of air with a dose rate of 2.2 kGy/h. At low dose gelatin hydrogels incorporating all the
available water were obtained. At higher doses above 50 kGy, the gelatin hydrogel samples show a curious shrinking phenomenon
due to the relatively high crosslinking density level achieved, so part of the available water is squeezed out from the gel
cage. The gelatin hydrogel samples were studied by mass fractionation analysis, by spectrophotometric and polarimetric analysis.
Further characterization was made by FT-IR spectroscopy and by thermal analysis (DSC, DTA and TGA) of the dried gelatin samples
after irradiation in comparison to a reference untreated sample. 相似文献
18.
Matija Strli? Irena Kralj Cigi? Jana Kolar May Cassar 《Polymer Degradation and Stability》2009,94(6):886-890
Historic parchment is a macromolecular material, which is complex due to its natural origin, inhomogeneity of the skin structure, unknown environmental history and potential localised degradation. Most research into its stability has so far focussed on thermal and structural methods of analyses.Using gas chromatographic analysis of the atmosphere surrounding parchment during oxidation, we provide the experimental evidence on the production of volatile aldehydes, which can be the products of lipid autoxidation. Oxidation of parchment with different aldehyde emissions was additionally followed in situ using chemiluminometry and the same techniques were used to evaluate the oxidation of differently delipidised parchment. It was shown that the production of peroxides and the emission of aldehydes from the material decrease with lower lipid content. Building on this evidence, we can conclude that the presence of lipids (either initially present in the skin or resulting from conservation intervention) leads to oxidative degradation of collagen and that the non-destructive analysis of the emission of volatiles could be used as a quick tool for evaluation of parchment stability. 相似文献
19.
P. Budrugeac 《Journal of Thermal Analysis and Calorimetry》2009,97(2):443-451
The thermo-oxidative degradation of a parchment recent manufactured from a goat skin has been investigated by TG/DTG, DSC
simultaneous analysis performed in static air atmosphere, at six heating rates in the range 3–15 K min−1. At the progressive heating in air atmosphere, the investigated material exhibits three main successive processes occurring
with formation of volatile products, namely the dehydration followed by two thermo-oxidative processes. The processing of
the non-isothermal data corresponding to the first process of thermo-oxidation was performed by using Netzsch Thermokinetics—a
Software Module for Kinetic Analysis. The dependence of activation energy, evaluated by isoconversional methods suggested
by Friedman, and Ozawa, Flynn and Wall, on the conversion degree and the relative high standard deviations of this quantity
show that the investigated process is a complex one. The mechanism and the corresponding kinetic parameters were determined
by Multivariate Non-linear Regression program. Three mechanisms, one consisting in four successive steps and two others in
five successive steps, exhibit the best F-test Fit Quality for TG curves. It was also used the previously suggested criterion, according to which the most probable
process mechanism correspond to the best agreement between E
FR
= E
FR
(α) (E
FR
is the activation energy evaluated by isoconversional method suggested by Friedman; α is the conversion degree) obtained
from non-isothermal experimental data and activation energy values, E
iso
, obtained by applying the differential method to isothermal data simulated using non-isothermal kinetic parameters. According
to this last criterion, the most probable mechanism of parchment oxidation consists in four successive steps. The contribution
of the thermo-oxidation process in the parchment damage by natural aging is discussed. 相似文献
20.
Noemi Proietti Valeria Di Tullio Cristina Carsote Elena Badea 《Magnetic resonance in chemistry : MRC》2020,58(9):840-859
Ancient vegetable tanned leathers and parchments are very complex materials in which both different manufacturing and deterioration processes make their study and chemical characterisation difficult. In this research, solid-state nuclear magnetic resonance (NMR) spectroscopy was applied to identify different tannin families (condensed and hydrolysable) in historical leather objects such as bookbindings, wall upholsters, footwear and accessories, and military apparel. Furthermore, leather deterioration with special focus on collagen gelatinisation was investigated. A comparison with Fourier transform infrared (FTIR) spectroscopy and micro-differential scanning calorimetry (micro-DSC) was also performed to support the 13C CP-MAS NMR findings and to point out the advantages and limitations of solid-state NMR in analysing historical and archaeological leathers. A wide database of NMR and FTIR spectra of commercial tannins compounds was also collected in order to characterise historical and archaeological leathers. 相似文献