Modern spectroscopic methods in non-invasive and micro-invasive analysis of paper degradation state

Papier został wynaleziony prawie 2000 lat temu i od tego czasu stał się najważniejszym nośnikiem informacji dla ludzkości. W tym czasie zebrano ogromną ilość książek, dokumentów i dzieł sztuki, z których wiele jest dziś bezcennych. Pomimo rozwoju elektronicznych nośników informacji, znaczenie papieru nie zmniejsza się. Popularność papieru wynika z jego wyjątkowych właściwości – – wytrzymałości, elastyczności, trwałości i łatwej dostępności – które zawdzięcza celulozie, swojemu głównemu składnikowi. Celuloza jest naturalnym polisacharydem składającym się z jednostek β-D-glukopiranozy połączonych wiązaniami (1→4)-glikozydowymi. Makrocząsteczki celulozy tworzą wielopoziomową strukturę, składającą się z fibryli elementarnych, mikro- i makrofibryli, budujących ściany komórkowe włókien roślinnych, które są głównym składnikiem papieru. Wysokiej jakości papier, jeśli jest prawidłowo przechowywany, degraduje powoli i może zachowywać swoje właściwości przez wieki. Jednakże papier słabej jakości w niekorzystnym otoczeniu może ulec rozkładowy w czasie ludzkiego życia. Degradacja papieru w skali makroskopowej objawia się jako żółknięcie i zwiększenie kruchości. Zmiany te są głównie wywoływane przez hydrolizę wiązań glikozydowych i utlenienie, prowadzące do powstawania grup karbonylowych. Hydroliza i utleniania są ściśle powiązane i mają katalityczny wpływ na siebie. Ich postęp prowadzi do zmian na każdym poziomie struktury włókien. Jedną z obserwowanych zmian jest rekrystalizacja polegająca na reorganizacji makrocząsteczek celulozy w bardziej uporządkowaną strukturę. Mimo, że rekrystalizacja nie jest procesem chemicznym, to możne wpływać na postęp hydrolizy i utleniania, dlatego powinna być uwzględniona w ocenie postępu degradacji papieru. W ramach niniejszej pracy opracowane zostały nowe metody analizy papieru, których zastosowanie pozwala na bardziej miarodajną ocenę postępu degradacji papieru, co pozwoliło również na pogłębienie zrozumienia mechanizmu degradacji celulozy w kontekście zależności między warunkami starzenia, różnymi ścieżkami degradacji i obserwowanymi jej skutkami. Posłużyły temu sztucznie postarzone papiery modelowe oraz naturalnie zdegradowane próbki średniowiecznych papierów ze szmat oraz papierów z transformatorów, które przebadano za pomocą chromatografii żelowej (SEC), fourierowskiej spektroskopii w podczerwieni (FT-IR), spektroskopii UV-VIS z wspomaganej obliczeniami TDDFT (UV-VIS/TDDFT) oraz dyfraktometrii rentgenowskiej (XRD). Wybrane metody pozwalają na ocenę stanu degradacji papieru przez określenie postępu depolimeryzacji, stężenia grup karbonylowych i zmian w krystaliczności celulozy.Paper was invented almost 2000 years ago and ever since it has become the most important information carrier for mankind. During this time an enormous amount of books, documents and works of art have been collected and many those artifacts are invaluable. Despite the development of electronic media, the importance of paper is not diminishing. The popularity of paper is mostly related to its unique properties – – strength, flexibility durability and availability – owed to the cellulose, its main component. Cellulose is a natural polysaccharide composed of β-D-glucopiranose units linked by (1→4)-glycosidic bonds. Macromolecules of cellulose form multileveled structure, consisting of elementary fibrils, microfibrils and macrofibrils that build cell walls of plant fibers, which are the main component of paper. Quality paper, if stored properly, degrades extremely slowly and preserves its properties for centuries. However, poor quality paper exposed to unfavorable environment can disintegrate during human lifetime. Deterioration of paper on the macroscopic scale is seen as yellowing and increasing brittleness. Those changes are induced primarily by hydrolysis of glycosidic bonds and oxidation which leads to formation of carbonyl groups. Hydrolysis and oxidation are interdependent and have a catalytic effect on each other. Their progress leads to numerous changes on each level of fiber structure. The one those changes is recrystallization is manifested by reorganization of cellulose macromolecules into more ordered structure. Recrystallization is not a chemical process although it can affect and be affected by hydrolysis and oxidation, therefore it is important to include it in assessing paper degradation state. In this study, the new methods were developed for paper analysis, which allow more meaningful assessment of paper degradation state. The use of those methods helped to increase the understanding the mechanism of cellulose degradation in terms of relationship between aging conditions, different degradation paths and its observed effects. To achieve the objectives artificially aged model papers were investigated along with naturally aged samples of ancient rag papers and insulation papers, by means of Size Exclusion Chromatography (SEC), Fourier-Transform Infrared Spectroscopy (FT-IR), UV-VIS spectroscopy aided with TDDFT calculations (UV-VIS/TDDFT) and X-Ray Diffractometry (XRD). The selection of methods allows the assessment of paper degradation state by characterization of depolymerization progress, development of carbonyl groups and recrystalization of cellulose

Reflective and photoacoustic infrared spectroscopic techniques in assessment of binding media in paintings

This study proposes a method to estimate the lipid content in binding media in paintings that can be used at any laboratory equipped with an infrared spectrometer. The lipid content estimator, termed greasiness index (GI), is defined as a ratio of lipid \nu(C=O) and protein amide I bands at 1743 and 1635 cm−1, respectively. Three Fourier transform infrared (FTIR) sampling techniques were evaluated for GI determination: reflective attenuated total reflection-ATR, specular reflection microscopy-\muSR and photoacoustic-PAS. A set of model painting samples containing three tempera binding media (casein, egg, egg + oil), seven pigments and one varnish type were used in the study. Multivariate analysis was used to evaluate the resulting data. A good reproducibility of GI was obtained by ATR and PAS but not with \mu SR. The discriminative power of the technique is higher for unvarnished samples, but, generally, the GI estimator can be used for the categorisation of binding media in large populations of painting samples analysed with the same FTIR technique (sampling technique, detection, etc.)

Circulating monocyte chemoattractant protein-1 in women with gestational diabetes.

Monocyte chemoattractant protein 1 (MCP-1) has been implicated as a key factor in the recruitment and activation of peripheral blood leukocytes in atherosclerotic lesions and adipose tissue. Elevated levels of circulating MCP-1 have been found in patients with type 1 and type 2 diabetes, as well as with coronary artery disease. In this study we compared serum MCP-1 concentrations between pregnant women with normal glucose tolerance (NGT), gestational diabetes mellitus (GDM) and non-pregnant healthy women. The group studied consisted of 62 patients with GDM (mean age 30.1 +/- 5.0 years) at 29.0 +/- 3.5 week of gestation, 64 pregnant women with NGT (mean age 30.0 +/- 4.7 years) at 29.2 +/- 2.9 week of gestation and 34 non-pregnant healthy women (mean age 29.8 +/- 4.7 years). Serum MCP-1 concentration was measured using an enzyme - linked immunosorbent assay. Median MCP-1 concentrations did not differ significantly between women with GDM (median 342.3 [interquartile range 267.9-424.4] pg/ml) and NGT (338.0 [274.7-408.2] pg/ml), but were markedly lower than those found in non-pregnant women (485.2 [409.6-642.4] pg/ml,

Experimental and theoretical study of the yellowing of ancient paper

Paper is the most widely used writing support due to the remarkable properties of its principal component - cellulose - one of the most abundant biomaterials present on Earth. However, due to the complexity of the material, an exhaustive picture of its degradation pathways is still missing. In this paper, we will present recent results and progresses obtained in the comprehension of the role of cellulose oxidation in the yellowing of ancient paper. Visible and ultraviolet spectra of cellulose in ancient paper samples and reference modern samples artificially aged have been interpreted with the aid of ab-initio Time-Dependent Density Functional Theory calculations. Through the comparison of measured and calculated absorption spectra, several oxidized forms of cellulose polymers, acting as chromophores, and responsible for ancient paper yellowing were identified. The relative concentration of ketones and aldehydic groups depends on the environmental conditions in which samples were stored along their life

La conservazione preventiva del patrimonio librario come possibile alternativa al restauro tradizionale

The present paper focuses on the close relation between library collections and their preservation environment, aiming, in particular, at highlighting the importance of promoting and sustaining the monitoring. The paper proposes some simple and ready-to-use technologies – smart monitoring – to prevent future damages

Degradation markers of fibroin in silk through infrared spectroscopy

Infrared spectroscopy (FTIR) is a commonly available tool in laboratories dealing with both degradation of materials and conservation of art objects to evaluate their condition. In this paper FTIR was engaged to study degradation of fi broin included in silk samples ( Bombyx mori ) arti fi cially aged at various conditions (oxygen, water vapor and volatile organic products) at temperature of 150 C. The results collected by Attenuated Total Re fl ectance/Fourier Transform Infrared Spectroscopy (ATR/FTIR) were validated by UV/ Vis, XRD and SEC analyses. Based on the results, the degradation estimators were veri fi ed and classi fi ed as: (1) crystallinity de fi ned as ratio of absorbance at 1620 and at 1656 cm 1 , A 1620 / A 1656 [1] , or at 1620 and 1699 cm 1 , A 1620 / A 1699 [2] ; or ratio of areas under fi tted curves of band at 1261 and 1230 cm 1 , P 1261 / P 1230 [3] , (2) oxidation e A 1620 / A 1514 and (3) depolymerization e P 1318 / P 1442 . Degradation gauges de fi ned in such a way indicate that upon arti fi cial aging water vapor and oxygen has the most profound impact on the progress of silk degradation. It also indicates that oxygen-lean conditions stabilize silk at elevated temperature