Monitoring degradation in paper: non-invasive analysis by unilateral NMR. Part II

doi:10.1016/j.jmr.2004.06.006

Journal of Magnetic Resonance

Volume 170, Issue 1, September 2004, Pages 113-120

https://doi.org/10.1016/j.jmr.2004.06.006 Get rights and content

Abstract

High quality paper samples have been oxidized with a specific oxidant to reproduce one of the possible causes of the aging of paper. All samples have been characterized by ¹³C CP–MAS NMR spectroscopy. The artificial aging of paper has been monitored using a standard NMR relaxometer and the results have been compared with the corresponding data obtained using an unilateral NMR relaxometer. Experimental values obtained with both techniques are in agreement, demonstrating that unilateral NMR relaxometric measurements constitute a suitable non-invasive method for assessing the degradation process of cellulose-based materials. The sensitivity of the non-invasive NMR method allows the detection of degradation even at a very early stage. Effects due to the sample volume and to the penetration depth have been investigated.

Introduction

In a previous paper [1], we have shown that it is possible to study the degradation of ancient books using unilateral NMR. The quality of the experimental data was sufficient for discriminating the state of paper preservation in the investigated books. The promising perspectives of this investigation prompted us to perform further experiments on cellulose-based materials to assess the limits and possibilities of the method on artificially aged paper.

Paper is one of the oldest and widely used man-made materials. It is mostly made from cellulose and water with small amounts of organic, inorganic and, possibly, dye additives [2]. While in earlier hand-made and modern high-quality machine papers only cellulose fibers are present [3], in low quality paper the cellulose is embedded in an hemicellulose and lignine matrix. In paper the water component is located in pores. The removal of even a small amount of water from these pores causes an irreversible destruction of the material [4]. In good quality modern paper, the pore size distribution was previously obtained using a well-established NMR method [5], [6], [7] which correlates the intensity of the signal of the mobile water component with the temperature. The obtained distribution is strongly asymmetric with a well defined maximum at ≈1.4 nm [7]. The average size of the water pools has been confirmed applying NMR techniques suitable for studying the spin diffusion process, i.e., dipolar-filter methods [8], [9] and 2D WISE [8]. Both techniques show that the water pools are surrounded by amorphous cellulose, whereas crystalline domains surround amorphous domains which in turn include the water pools [7]. Moreover, dipolar-filter methods allow a rough evaluation of the distance between crystalline domains and the water pools. This distance is about 3 nm. These results agree well with results obtained by transmission electron microscopy (TEM) [10].

Due to the small average size (≅1.4 nm) of water filled pores, in dry material, the diffusion process of the confined water is negligible. We have confirmed this observation using the Pulsed Field Gradient method. In fact, in dry paper, even when a strong gradient of 1000 G/cm is applied the diffusion coefficient of the water confined in the pores is too small to be measured.

The degradation of paper is a complex phenomenon due to different causes such as the biotic action of fungi and bacteria and/or chemical attack. In chemical terms, the degradation of paper is essentially the conversion of fibrous and highly crystalline cellulose into a largely amorphous degraded material. Such transformation is the result of different, complex processes among which acid hydrolysis is by far the most important. In all cases of paper degradation, a loss of water was previously observed [4] associated with a shortening of the spin–spin relaxation time T₂ of the water confined in the pores. Relaxometric NMR methods have been shown to be valuable in assessing the quality of paper with regard to an early detection of enzymatic attack [11]. The most sensible parameter is the spin-spin relaxation time T₂ of the H₂O component. In fact, after enzymatic attack, a net decrease of T₂ has been reported. Note that the same T₂ shortening is also present in dry, degraded wood [12].

Standard NMR methods are particularly suitable for studying materials and are generally considered as non-invasive. However, they do require some sampling often forbidden when studying rare and precious materials such as old books and incunabula. The sampling can be avoided using an unilateral NMR instrument such as the Eureka Mouse¹ (EM10), which is a variant of the NMR-MOUSE² [1], [13]. These sensors are portable and their use is fully non-invasive, allowing the measurement of a few NMR parameters such as the spin density, the spin–spin and the spin–lattice relaxation times. The sensor can be positioned near intact objects in different positions.

In a previous paper [1], we have indeed demonstrated that unilateral NMR is a suitable instrument to assess the quality of ancient paper made of rags. However, many questions are still open. These are for instance “Can the relaxation data measured in paper with an unilateral instrument be directly used for assessing the degradation process?” and “What is the limit of detection of the degradation process attainable with conventional and unilateral relaxometers?” To answer these questions a systematic study of one type of artificially aged paper was performed. It is worth noticing that the use of artificially aged paper samples allows a direct comparison of relaxation data obtained by unilateral NMR relaxometry and by measurements in a homogenous field.

In this work a high quality paper has been oxidized with a specific oxidant to reproduce one of the possible causes of paper aging. The artificial aging of the sheet of paper is then monitored using the unilateral relaxometer, and the results are compared with the corresponding ones obtained using a conventional NMR relaxometer. All paper samples have been also characterized by ¹³C CP–MAS NMR spectroscopy.

Section snippets

Samples

The cellulose substrate was Whatman paper N. 1 filter paper. This type of paper is obtained from cotton “linters” and can be considered as pure cellulose. Its degree of polymerization is 1230. Sodium metaperiodate (NaIO₄ 99.8%) was obtained from Sigma–Aldrich and was used without further purification.

Oxidation reaction

The oxidation of cellulose has been performed with sodium metaperiodate, a specific oxidizing agent. The reaction cleaves the C2–C3 bond and involves the formation of a 2,3-dialdehyde following the

¹³C CP–MAS NMR spectroscopy

The damage induced on cellulose by the oxidation treatment was characterized by ¹³C CP–MAS NMR spectroscopy. Fig. 1A shows the ¹³C CP–MAS spectrum of untreated Whatman paper along with the assignment of the resonances. The “c” resonances are from the crystalline domains, while the broad “a” resonances are from the amorphous environment [25]. In Figs. 1B, D, F, and H the spectra of Whatman paper after oxidation with 0.1 M NaIO₄ for 2, 24, 48, and 72 h are shown, and in Figs. 1C, E, G, and I the

Conclusion

The aging of paper has been mimicked by an oxidation reaction. The damage induced by oxidizing the cellulose fibers of Whatman paper has been followed with ¹³C CP–MAS NMR spectroscopy and by measurements of the transverse relaxation in homogeneous and inhomogeneous fields. In dry material, even at an early stage, the degradation of paper is characterized by a shortening of the spin–spin relaxation time of the confined water. This can be observed with a conventional, minimal-invasive NMR

Acknowledgements

Thanks are due to Dr. R. Lamanna of Enea (Trisaia) for the software providing the data inversion. Thanks are also due to Dr. Fabio Tedoldi and Roberto Melzi of Bruker Biospin Milano. This work was carried out as a part of the Eureka project Σ!2214—Eurocare Mouse. We acknowledge the support of Prof. A. Guarino.

References (30)

B. Blümich et al.
Degradation of historical paper: nondestructive analysis by the NMR-MOUSE^®
J. Magn. Reson.
(2003)
M. Paci et al.
NMR study of paper
Carbohydr. Polym.
(1995)
G. Eidmann et al.
The NMR MOUSE, a mobile universal surface explorer
J. Magn. Reson. A
(1996)
S. Margutti et al.
Physical–chemical characterization of acrylic polymers grafted on cellulose
Polymer
(2002)
G. Metz et al.
Ramped-amplitude cross polarization in magic-angle-spinning NMR
J. Magn. Reson. A
(1994)
B. Blümich et al.
The NMR-Mouse: construction, excitation and applications
Magn. Reson. Imag.
(1998)
K.P. Whittall et al.
Investigation of analysis techniques for complicated NMR relaxation data
J. Magn. Reson.
(1991)
G.C. Borgia et al.
Uniform-penalty inversion of multiexponential decay data
J. Magn. Reson.
(1998)
G.C. Borgia et al.
Uniform-penalty inversion of multiexponential decay data: II. Data spacing, T₂ data, systematic data errors and diagnostics
J. Magn. Reson.
(2000)
F. Balibanu et al.
NMR in inhomogeneous magnetic fields
J. Magn. Reson.
(2000)

C. Casieri et al.

Self-diffusion coefficient by single-sided NMR

J. Magn. Reson.

(2003)

C. Federici et al.

Ancient paper and its NMR characterization

Sci. Technol. Cultur. Heritage

(1996)

E.W. Hansen et al.

Low-temperature phase transition of water confined in mesopores probed by NMR. Influence on pore size distribution

J. Phys. Chem.

(1996)

E.W. Hansen et al.

Pore structure characterization of porous silica by ¹H NMR using water, benzene, and cyclohexane as probe molecules

J. Phys. Chem.

(1996)

Cited by (54)

Applications of NMR spectroscopy in cultural heritage science
2023, Comprehensive Inorganic Chemistry III, Third Edition
Nuclear magnetic resonance spectroscopy has advanced our understanding of cultural heritage objects. Solution NMR, solid state NMR, unilateral NMR, magnetic resonance imaging (MRI) and other MR techniques have been used on a wide variety of materials such as stone, ceramics, paintings, biological remains, paper, wood, textiles, resins, gums, and synthetic materials. This review highlights NMR studies that provide structural and chemical identification, moisture content and distribution, uncovers artistic techniques, determines geographical origins, identifies constituent materials of an object and helps to determine the best cleaning or treatment method for conservation. In addition, physical and chemical transformations and structural modifications due to deterioration of an object can be monitored by NMR methods, and this information provides conservators with clues as to the most appropriate methods of preservation of a unique artifact. With the continued development of NMR pulse sequences, probes and sensors, the sensitivity and utility of NMR spectroscopy in cultural heritage continues to grow.
Direct non-invasive molecular analysis of packaging label to assist wine-bottle authentication
2020, Microchemical Journal
Citation Excerpt :
The most common forensic methods for the analysis of organic components of paper and inks from documents are Thin Layer Chromatography (TLC) [6-8] and Capillary Electrophoresis (CE) [9-12]. Other important techniques are Gas Chromatography-Mass Spectrometry (GC–MS) [13,14], Direct Analysis in Real Time Mass Spectroscopy (DART-MS) [15-17] and Nuclear Magnetic Resonance (NMR) [18-20], which have also been employed for the detection of the molecular constituents of documents with minimal destructive sampling to study the manufacturing process including pulp composition and contaminants. Each of these techniques has their own advantages and limitations.
Alcoholic beverages, especially great wines and spirits, are prime targets for counterfeiters. The simplest form of wine fraud involves fixing counterfeit labels of expensive wines to bottles of less expensive wine. However, time-consuming analytical techniques requiring liquid sampling are mainly used for authentication purposes, which irremediably degrade the value of the bottle. This work aims to develop a new diagnostic tool based on the direct analysis of label matrix and ink in order to obtain valuable information that would enable a preliminary non-destructive authentication. Raman and infrared spectroscopies have been applied for fast, reproducible and discernible molecular characterization since both analytical techniques are strictly non-invasive and do not require sample preparation. They were successfully applied to a selected number of genuine and counterfeited bottles (Pauillac, France) and a series of bottles which goes from 1969 to 2010 belonging to the same producer (Pomerol, France). Raman spectroscopy and infrared spectroscopy showed a great complementarity to clarify the molecular composition of label and inks. As a general overview, pigments are not useful for discrimination purpose in the pairs of original and counterfeited samples. However, several mismatch in label composition were identified, allowing the differentiation among samples. With respect to the second batch of bottles, Raman spectroscopy was able to trace the materials used in labels and inks, giving evidences about the chronologic order of manufacture. Despite the limited number of samples, mainly due to their uniqueness, the classification power of the proposed methodology has been clearly proven.
The immune reaction and degradation fate of scaffold in cartilage/bone tissue engineering
2019, Materials Science and Engineering C
Citation Excerpt :
Ultrasound elasticity imaging (UEI) can characterize structural, functional and compositional change of biodegradable scaffolds via phase-sensitive speckle track [243]. Further, other parameters, such as pH, scaffold distribution, cell viability, can be measured through non-invasive and non-destructive methods including confocal laser scanning microscopy (CLSM), nuclear magnetic resonance (NMR), low field NMR, optical coherence microscopy (OCM) [244–250]. Besides, parameters like pH are reflection of the degradation profile as well.
Tissue engineering with scaffolds provides novel prospects for bone/cartilage damage healing. Previous studies mainly focus on the development of physical/chemical property of scaffold and their efficiency on tissue regeneration. The biocompatibility and biodegradation of scaffold have been questioned with their rapidly increased application, since the ultimate clinical application requires biological safety and efficiency of biomaterials. After scaffolds are implanted in living organisms, excessive inflammatory response and foreign body reaction may compromise tissue healing outcomes, or eventually lead to the failure of regeneration. Further, scaffolds degradation and degraded derivatives may elicit immunogenic reaction, cause environmental change, influence encapsulated drug/growth factor release and cellular activity. Hence, the understanding of the degradation characteristics of various biomaterials is required as well. Non-invasive monitoring the fate of scaffolds inside the body needs to be explored for temporally and longitudinally optical observation. The review mainly aims to provide a retrospective summary and discussion of the biocompatibility, immune response and fate of scaffold in cartilage/bone tissue engineering. The continuing development of sophisticated biocompatible and biomimetic scaffolds will eventually lead to clinical application which can improve the quality of patients' care and life.
Solid-state NMR of nanocrystals
2019, Annual Reports on NMR Spectroscopy
Recent advances in solid-state nuclear magnetic resonance (NMR) spectroscopy and dynamic nuclear polarization (DNP) of nanostructured materials are reviewed. A first group of materials is based on crystalline nanocellulose (CNC) or microcrystalline cellulose (MCC), which are used as carrier materials for dye molecules, catalysts or in combination with heterocyclic molecules as ion conducting membranes. These materials have widespread applications in sensorics, optics, catalysis or fuel cell research. A second group are metal oxides such as V-Mo-W oxides, which are of enormous importance in the manufacturing process of basic chemicals. The third group are catalytically active nanocrystalline metal nanoparticles, coated with protectants or embedded in polymers. The last group includes of lead-free perovskite materials, which are employed as environmentally benign substitution materials for conventional lead-based electronics materials. These materials are discussed in terms of their application and physico-chemical characterization by solid-state NMR techniques, combined with gas-phase NMR and quantum-chemical modelling on the density functional theory (DFT) level. The application of multinuclear ¹H, ²H, ¹³C, ¹⁵N and ²³Na solid state NMR techniques under static or MAS conditions for the characterization of these materials, their surfaces and processes on their surfaces is discussed. Moreover, the analytic power of the combination of these techniques with DNP for the identification of low-concentrated carbon and nitrogen containing surface species in natural abundance is reviewed. Finally, approaches for sensitivity enhancement by DNP of quadrupolar nuclei such as ¹⁷O and ⁵¹V are presented that enable the identification of catalytic sites in metal oxide catalysts.
Physical and chemical properties of traditional and water-mixable oil paints assessed using single-sided NMR
2017, Microchemical Journal
Citation Excerpt :
Putting the physical properties of these WMO paint alternatives in context with TOs is important for both scientific and conservation purposes. Single-sided nuclear magnetic resonance (NMR) has been used to non-invasively study objects and chemical processes including oil well logging [4,5], food [6–8], manufacturing procedures [9,10], paintings [11–15], instruments [16], ceramics [17–19], paper [20], and building materials [21]. The use of permanent magnets in single-sided devices greatly reduces engineering and operation complexity associated with traditional NMR equipment.
Single-sided NMR and gas chromatography were used in tandem to investigate the physical and chemical differences between traditional linseed oil paint and water-mixable oil paint. Water-mixable oil paints contain an emulsifier that confers water miscibility, but it may also affect the curing process and the intermolecular network formed in a cured paint film. Comparisons of paint samples of different compositions and ages show that the emulsifier changes both the chemical and physical properties of the paint films, though at different curing times and to different extents depending on the paint formulation. This research highlights the utility of NMR relaxometry in cultural heritage analysis, and suggests further study into the effects of agents affecting the curing process and reactions within a paint film.
Alcoholic nanolime dispersion obtained by the insolubilisation-precipitation method and its application for the deacidification of ancient paper
2017, Colloids and Surfaces A: Physicochemical and Engineering Aspects
Nanolime dispersions for the deacidification of ancient paper constitute a valid alternative to the lime traditional ones. Their efficacy depends on particles size, polydispersity and agglomeration that can be controlled depending on the preparation method.
In this work, nanolime preparation by insolubilisation-precipitation method is reported. Nanoparticles dispersed in a water-isopropanol mixture were obtained without any manipulation of the dispersion. The stability of the dispersion together with particle size and morphology were found to be dependent on water to isopropanol molar ratio and on the synthesis temperature.
One of the dispersion was applied on a manuscript to assess its efficiency.

View all citing articles on Scopus

View full text

Monitoring degradation in paper: non-invasive analysis by unilateral NMR. Part II

Abstract

Introduction

Section snippets

Samples

Oxidation reaction

13C CP–MAS NMR spectroscopy

Conclusion

Acknowledgements

J. Magn. Reson.

Carbohydr. Polym.

J. Magn. Reson. A

Polymer

J. Magn. Reson. A

Magn. Reson. Imag.

J. Magn. Reson.

J. Magn. Reson.

J. Magn. Reson.

J. Magn. Reson.

J. Magn. Reson.

Ancient paper and its NMR characterization

Sci. Technol. Cultur. Heritage

Low-temperature phase transition of water confined in mesopores probed by NMR. Influence on pore size distribution

J. Phys. Chem.

Pore structure characterization of porous silica by 1H NMR using water, benzene, and cyclohexane as probe molecules

J. Phys. Chem.

¹³C CP–MAS NMR spectroscopy

Pore structure characterization of porous silica by ¹H NMR using water, benzene, and cyclohexane as probe molecules