scholarly journals Colour stability of wood coatings pigmented with natural indigo from Isatis tinctoria after accelerated weathering

2021 ◽  
Author(s):  
Juha Jordan ◽  
Roosa Helander ◽  
Päivi Laaksonen
Keyword(s):  
Accelerated Weathering ◽  
Colour Stability ◽  
Isatis Tinctoria ◽  
Wood Coatings

scholarly journals In Situ Performance Assessment and Evaluation of Hydrophobic and Ultraviolet Protective Treatments for Historic Log Structures

2015 ◽  
Vol 38 ◽  
pp. 100-111
Author(s):  
Courtney Magill ◽  
Frank Matero
Keyword(s):  
Field Research ◽  
Accelerated Weathering ◽  
Assessment And Evaluation ◽  
Appropriate Treatment ◽  
Wood Coatings ◽  
Subsequent Phase ◽  
Initial Results ◽  
Ongoing Project

Beginning in the summer of 2015, research was conducted on protective wood coatings and accelerated weathering testing methods for architectural log and timber. A rack for supplementary natural weathering testing of hydrophobic and ultraviolet protective surface treatments for logs was also erected as a subsequent phase at Grand Teton National Park. This laboratory and field research is part of an ongoing project to develop an appropriate treatment for historic log structures in the region that will preserve their original fabric while maintaining the intended historic appearance of the buildings, i.e., unpainted. The weathering rack will be in place for upwards of five years to verify the lab-based results from Phase I and to determine the long-term durability of the chosen treatments on already aged materials in situ. This report addresses the methods and materials for preparation of the weathering rack and samples as well as the methods being used to monitor their progress and initial results. Readings will be taken yearly to monitor the effects of weathering on each treatment.

Simple Modification Measurement of Photodegradability of Polymers by using Photo-induced Chemiluminescence Technique

2013 ◽  
Vol 10 (2) ◽  
pp. 51
Author(s):  
Siti Farhana Zakaria ◽  
Keith R Millington
Keyword(s):  
Free Radicals ◽  
Organic Materials ◽  
Oxidative Degradation ◽  
Working Life ◽  
Bimolecular Reaction ◽  
Synthetic Polymers ◽  
Accelerated Weathering ◽  
Simple Modification ◽  
Uv Absorbers ◽  
Irradiation Period

Polymers and organic materials that are exposed to sunlight undergo photooxidation, which leads to deterioration of their physical properties. To allow adequate performance under outdoor conditions, synthetic polymers require additives such as antioxidants and UV absorbers. A major problem with optimising polymer formulations to maximise their working life span is that accelerated weathering tests are empirical. The conditions differ significantly from real weathering situations, and samples require lengthy irradiation period. Degradation may not be apparent in the early stages of exposure, although this is when products such as hydroperoxides are formed which later cause acceleration of oxidation. A simple way of quantifying the number of free radicals presents in organic materials following exposure to light or heat is by measuring chemiluminescence (CL) emission. Most polymers emit CL when they undergo oxidative degradation, and it originates from the bimolecular reaction of macroperoxy radicals which creates an excited carbonyl.

PRINTING. The ageing resistance of offset and electrophotographic prints

2012 ◽  
Vol 27 (4) ◽  
pp. 739-749
Author(s):  
Silva Grilj ◽  
Tadeja Muck ◽  
Diana Gregor-Svetec
Keyword(s):  
Relative Humidity ◽  
Surface Coating ◽  
Accelerated Ageing ◽  
Colour Stability ◽  
Light Fastness ◽  
Moist Heat ◽  
Printing Technique ◽  
Lower Light ◽  
Recycled Fibres ◽  
2D And 3D

Abstract The moist heat (80°C and 65% relative humidity) and light (xenon arc lamp) treatments of accelerated ageing were applied to investigate the colour stability of offset and electrophotographic prints on papers made of virgin and I 00% recycled fibres. The prints were evaluated using spectrophotometric measurements and additional colour differences calculations. In addition to the colour differences, the 2D and 3D colour gamuts are presented. The results reveal the different colour stability of prints. The effect depends on the type of accelerated ageing, printing technique, composition of ink and paper characteristics. Moist heat ageing has less influence on colour stability than light ageing. The electrophotographic prints show better ageing resistance than offset prints. The intluence of ink on print light fastness is considerable. Azo pigments in magenta and yellow have lower light fastness than phthalocyanine pigments in cyan or carbon black. The surface coating has an intluence on light fastness of prints. Meanwhile, prints on recycled papers show similar colour stability compared to prints on papers made of virgin fibres

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