Over the last 8 years, the Journal of Thermal Analysis and Calorimetry published a few papers related to leather and parchment conservation science. The titles are as follows:
2000
Volume 59, Numbers 1-2/ January
M. Odlyha, G. M. Foster, N. S. Cohen and R. Larsen; “Characterisation of Leather Samples by Non-invasive Dielectric and Thermomechanical Techniques”, pp.587-600
Abstract:
A description is given how the dielectric coaxial technique measuring in the microwave region has been used for monitoring drying processes in leather samples. It is also shown how the coupling of this technique together with dynamic mechanical analysis enables the simultaneous recording of changes in the dielectric properties, related to the moisture content of the material, together with the mechanical properties as a function of time or temperature. The samples studied include unaged and artificially aged goat and calf leathers. Measurements using the dynamic mechanical analyser are presented over a range of temperature which includes the shrinkage temperature. During the drying process, values of mechanical modulus or displacement and dielectric permittivity are recorded as a function of time or temperature which includes the temperature range of leather shrinkage, and from previous research report of Larsen this has been associated with the chemical state of the leather samples.
2003
Volume 71, Number 3/ March
M. Odlyha, N. S. Cohen, G. M. Foster, A. Aliev, E. Verdonck and D. Grandy; “Dynamic mechanical analysis (DMA), 13C solid state nmr and micro-thermomechanical studies of historical parchment”, pp.939-951
Abstract:
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.
2004
Volume 77, Number 3 / September
P. Budrugeac, L. Miu, C. Popescu and F.-J. Wortmann; “Identification of collagen-based materials that are supports of cultural and historical objects”, pp.975-985
Abstract:
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.
2005
Volume 82, Number 3 / November
G. Della Gatta, E. Badea, R. Ceccarelli, T. Usacheva, A. Mašic and S. Coluccia; “Assessment of damage in old parchments by DSC and SEM”, pp. 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.
2006
Volume 85, Number 1 / July
B. Roduit and M. Odlyha; “Prediction of thermal stability of fresh and aged parchment”, pp.157-164
Abstract:
The hyphenated thermal analysis-mass spectrometry technique (TA-MS) was applied for the investigation of the thermal behaviour 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 behaviour 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 behaviour 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 thermo analytical methods for investigating behaviour of such complicated systems as leather or parchment.
2007
Volume 88, Number 3 / June
P. Budrugeac, L. Miu and M. Souckova; “The damage in the patrimonial books from Romanian libraries”, pp.693-698
Abstract:
The thermal analysis methods (TG, DTG, DSC, methods for shrinkage temperature evaluation) and scanning electron microscopy (SEM) were used for investigation of the thermal behaviour and surface morphology of some recent manufactured parchments and vegetable tanned leathers, patrimonial parchments and leathers proceeded from Romanian libraries. At the progressive heating in static air atmosphere and in the temperature range of 20–600°C, all investigated materials exhibit three main successive processes, associated with the dehydration and thermo-oxidative degradations. The rate of the first thermo oxidative process, temperatures corresponding to the maximum rate of the second thermooxidative process and shrinkage temperature were associated with the damage of the investigated materials due to environmental impact. Parchments and leathers surfaces were characterized by SEM, and specific morphological criteria were suggested for damage assessments. These criteria were correlated with the results obtained by thermal analysis methods.
2008
Volume 91, Number 1 / January
E. Badea, L. Miu, P. Budrugeac, M. Giurginca, A. Mašić, N. Badea and G. Della Gatta; “Study of deterioration of historical parchments by various thermal analysis techniques complemented by SEM, FTIR, UV-Vis-NIR and unilateral NMR investigations”, pp.17-27
Abstract:
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.
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