scholarly journals Removal of a Past Varnish Treatment from a 19th-Century Belgian Wall Painting by Means of a Solvent-Loaded Double Network Hydrogel

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2651
Author(s):  
Ehab Al-Emam ◽  
Victoria Beltran ◽  
Steven De Meyer ◽  
Gert Nuyts ◽  
Vera Wetemans ◽  
...  
Keyword(s):  
Ftir Spectroscopy ◽  
Polymeric Materials ◽  
Wall Painting ◽  
Solvent Mixtures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrogel Composite ◽  
Varnish Layer ◽  
Last Judgment ◽  
Cleaning Methods

Polymeric materials have been used by painting conservator-restorers as consolidants and/or varnishes for wall paintings. The application of these materials is carried out when confronting loose paint layers or as a protective coating. However, these materials deteriorate and cause physiochemical alterations to the treated surface. In the past, the monumental neo-gothic wall painting ‘The Last Judgment’ in the chapel of Sint-Jan Berchmanscollege in Antwerp, Belgium was treated with a synthetic polymeric material. This varnish deteriorated significantly and turned brown, obscuring the paint layers. Given also that the varnish was applied to some parts of the wall painting and did not cover the entire surface, it was necessary to remove it in order to restore the original appearance of the wall painting. Previous attempts carried out by conservator-restorers made use of traditional cleaning methods, which led to damage of the fragile paint layers. Therefore, gel cleaning was proposed as a less invasive and more controllable method for gently softening and removing the varnish. The work started by identifying the paint stratigraphy and the deteriorated varnish via optical microscopy (OM), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectroscopy. A polyvinyl alcohol–borax/agarose (PVA–B/AG) hydrogel loaded with a number of solvents/solvent mixtures was employed in a series of tests to select the most suitable hydrogel composite. By means of the hydrogel composite loaded with 10% propylene carbonate, it was possible to safely remove the brown varnish layer. The results were verified by visual examinations (under visible light ‘VIS’ and ultraviolet light ‘UV’) as well as OM and FTIR spectroscopy.

Synthesis of Galactomannan Sulfate-Citrate

2022 ◽  
Vol 1049 ◽  
pp. 218-223
Author(s):  
Aleksandr S. Kazachenko ◽  
Yuriy N. Malyar ◽  
Anna S. Kazachenko
Keyword(s):  
Biological Activity ◽  
Ftir Spectroscopy ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
X Ray ◽  
Mixed Ester ◽  
First Time ◽  
Derivatives Of

Sulfated derivatives of polysaccharides have anticoagulant, hypolipedimic and other biological activity. In this work, a complex mixed ester of galactomannan, its sulfate-citrate, was obtained for the first time. The introduction of citrate and sulfate groups was proved by FTIR spectroscopy by the appearance of corresponding absorption bands. It was shown by X-ray diffraction that the introduction of the citrate group leads to the amorphization of the galactomannan structure.

Comparison between Rice Husk Ash and Commercial Silica as Filler in Polymeric Composites

2016 ◽  
Vol 869 ◽  
pp. 209-214 ◽  
Author(s):  
Iara Janaína Fernandes ◽  
Daiane Calheiro ◽  
Emanuele Caroline Araújo dos Santos ◽  
Roxane Oliveira ◽  
Tatiana Louise Avila de Campos Rocha ◽  
...  
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Polymeric Materials ◽  
Fluidized Bed Reactor ◽  
Specific Weight ◽  
High Energy ◽  
Loss On Ignition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Sources

The use of rice husk ash (RHA) as filler in polymeric materials has been studied in different polymers. Research reported that RHA may successfully replace silica. The silica production process using ore demands high energy input and produces considerable amounts of waste. Therefore, the replacement of silica by RHA may be economically and environmentally advantageous, reducing environmental impact and adding value to a waste material. In this context, this study characterizes and compares RHA of different sources (moving grate and fluidized bed reactor) with commercially available silicas to assess performance as filler in polymeric materials. Samples were characterized by X-ray fluorescence, loss on ignition, X-ray diffraction, grain size, specific surface area, specific weight, and scanning electron microscopy. The results show that RHA may be used as a filler in several polymeric materials.

scholarly journals Identification of sugars and phenolic compounds in honey powders with the use of GC–MS, FTIR spectroscopy, and X-ray diffraction

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Katarzyna Kozłowicz ◽  
Renata Różyło ◽  
Bożena Gładyszewska ◽  
Arkadiusz Matwijczuk ◽  
Grzegorz Gładyszewski ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Ftir Spectroscopy ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Coumaric Acid ◽  
X Ray Diffraction ◽  
Phenyllactic Acid ◽  
X Ray ◽  
Spectrometry Analysis

Abstract This work aimed at the chemical and structural characterization of powders obtained from chestnut flower honey (HFCh) and honey with Inca berry (HBlu). Honey powders were obtained by spray drying technique at low temperature (80/50 °C) with dehumidified air. Maltodextrin (DE 15) was used as a covering agent. The isolation and evaluation of phenolic compounds and sugars were done by gas chromatography–mass spectrometry analysis. Scanning electron microscopy, Fourier-transform infrared (FTIR) spectroscopy, and X-ray diffraction were performed to determine the morphology of the studied honey powders. The obtained results showed that the content of simple sugars amounted to 72.4 and 90.2 g × 100 g−1 in HFCh and HBlu, respectively. Glucose was found to be the dominant sugar with a concentration of 41.3 and 51.6 g × 100 g−1 in HFCh and HBlu, respectively. 3-Phenyllactic acid and ferulic acid were most frequently found in HFCh powder, whereas m-coumaric acid, benzoic acid, and cinnamic acid were the most common in HBlu powder. The largest changes in the FTIR spectra occurred in the following range of wavenumbers: 3335, 1640, and below 930 cm−1. The X-ray diffraction profiles revealed wide peaks, suggesting that both honey powders are amorphous and are characterized by a short-range order only.

X-ray diffraction and FTIR spectroscopy of heat treated R2O3:3Ga2O3:4B2O3 systems

2002 ◽  
Vol 237-239 ◽  
pp. 874-878 ◽  
Author(s):  
E. Beregi ◽  
A. Watterich ◽  
J. Madarász ◽  
M. Tóth ◽  
K. Polgár
Keyword(s):  
Ftir Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated

An Area-Imaging Proportional Counter for X-Ray Diffraction

1980 ◽  
Vol 24 ◽  
pp. 161-166 ◽  
Author(s):  
C. Richard Desper ◽  
Ronald Burns
Keyword(s):  
Data Acquisition ◽  
Proportional Counter ◽  
Orientation Angle ◽  
Polymeric Materials ◽  
Bragg Angle ◽  
Acquisition Time ◽  
Time Interval ◽  
X Ray Diffraction ◽  
Oriented Polymers ◽  
X Ray

Slow data acquisition rates have, in the past, limited the use of X-ray diffraction for characterization of polymeric materials. Photon counting techniques yield quantitative data in digital form for computer analysis. However, a great deal of data acquisition time is required when data is taken sequentially; i.e., when each intensity determination (at a particular goniometer setting) requires a separate time interval, during which intensity at other angle values is ignored. The problem is particularly acute for oriented polymers since two or more diffraction angles are involved: The Bragg angle along with at least one orientation angle. For this reason, an area-imaging (two-dimensional) proportional counter has been developed for use with a four-circle X-ray diffraction system. Although basically a single-crystal unit, this goniometer has been used in this laboratory and others for studies of oriented polymers. The receiving pinhole collimator and aperture have been removed, and the area-imaging counter has been mounted on the detector arm track. The original receiving aperture is still used for alignment, and the area detector Is positioned with its center at the receiving aperture center position.

Erucamide-Nanoclay Systems Obtained by Intercalation Process

2017 ◽  
Vol 899 ◽  
pp. 36-41 ◽  
Author(s):  
Josiane R. Silvano ◽  
J.M.M. Mello ◽  
Lucinao Luiz Silva ◽  
Humberto Gracher Riella ◽  
Márcio Antônio Fiori
Keyword(s):  
Differential Scanning Calorimetry ◽  
Reaction Medium ◽  
Film Surface ◽  
Polymeric Materials ◽  
Polymeric Films ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Intercalation Process ◽  
The Matrix

A major challenge in the manufacture of films for polymeric packaging is the definition and setting of the friction coefficient (FCO) for the film surfaces. The FCO values are established with the incorporation of additives during the processing of the polymeric films. But, the homogenization of these additives in the polymeric matrix is very difficult. The additives have different polarity that the matrix polymeric and not are mixable. So, these additives migrate for the surface of the polymeric films easily. Several molecules are used as sliding additives, but among the most efficient are the amides molecules, highlighting the erucamide. This molecule promotes the decrease of the FOC but due its quick migration for the polymeric film surface provides numerous problems for the manufacture of the polymeric packaging and during its application as the product. In this work a nanocomposite (MMT-ERU) was obtained by an intercalation process to improve the compatibility between the polymeric materials and the erucamide molecules. The results shown in this work refers to the studies about the intercalation processes of the erucamide molecules into nanoclays (montmorillonite) to obtain the nanocomposite MMT-ERU. The effect of the temperature and the percentage of the nanoclay in the intercalation processes were studied. The results of x-ray diffraction and differential scanning calorimetry shown that erucamide molecules were intercalated in the nanoclay structures and that intercalation efficiency depends positively of the temperature and percentage amount of the nanoclay in the reaction medium.

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