Investigation on Aesthetic and Water Permeability of Surface Protective Material under Accelerated Weathering

In this paper, experiments were conducted on the effects of aesthetic and durability of three representative surface protective material under accelerated weathering test for 5000 h. First, the adaptability of the surface protective material coating to the substrate was proven by examining the aesthetic properties and the water permeability of the building materials. Second, the pollutant resistance of the surface protective material coating to artificial stain was assessed using xenon-arc light. The result shows that the appearance of the silane types did not change significantly, and the water permeability was improved. In addition, the silicate types did not improve water permeability and the surface color was changed. Fluor- resin types effectively improved the water permeability, but the surface color became dark. Sample measurements showed changes in the average width of the contamination after weathering, with an increase after spray cleaning and ultrasonic cleaning. However, it was observed that after washing the pollution average width of all specimens due to weathering at 5000 h was almost as much or smaller than the initial value.

Effects of accelerated weathering test on the properties of larch wood

To investigate the changes of larch wood properties under the influence of long-standing exposure to the environment, the QUV accelerated weathering tester (fluorescent UV and condensation testers) was used to accelerate the weathering of wood within a given preset time, and the changes were studied by analogue simulation. The wood color changed noticeably under different weathering time, and it gradually darkened from light yellow to deep reddish brown. Scanning electron microscopic (SEM) analysis revealed that as the weathering time increased, the cell wall was broken, the pits were cracked, and the tracheids were damaged. The results of the energy spectrum analysis (O/C (oxygen/carbon)) showed an increasing trend in the ratio, indicating that the wood underwent an oxidation reaction induced by light. From the values of the two testing indexes and their change patterns with weathering time, the same trend was observed, with the values of modulus of elasticity (MOE) in static bending being greater than that in dynamic bending Ed (the dynamic modulus of elasticity). However, the variability of MOE was greater than that of Ed. A comparative analysis of the two detection indicators was performed. The relationship between the proposed combined correction Ed and weathering time was: y = 0.0000001017 t2 – 0.0006 t + 9.77.

Comparison of the Physico-Mechanical and Weathering Properties of Wood–Plastic Composites Made of Wood Fibers from Discarded Parts of Pomelo Trees and Polypropylene

The purpose of this study is to compare the characteristics of wood–plastic composites (WPCs) made of polypropylene (PP) and wood fibers (WFs) from discarded stems, branches, and roots of pomelo trees. The results show that the WPCs made of 30–60 mesh WFs from stems have better physical, flexural, and tensile properties than other WPCs. However, the flexural strengths of all WPCs are not only comparable to those of commercial wood–PP composites but also meet the strength requirements of the Chinese National Standard for exterior WPCs. In addition, the color change of WPCs that contained branch WFs was lower than that of WPCs that contained stem or root WFs during the initial stage of the accelerated weathering test, but the surface color parameters of all WPCs were very similar after 500 h of xenon arc accelerated weathering. Scanning electron microscope (SEM) micrographs showed many cracks on the surfaces of WPCs after accelerated weathering for 500 h, but their flexural modulus of rupture (MOR) and modulus of elasticity (MOE) values did not differ significantly during weathering. Thus, all the discarded parts of pomelo trees can be used to manufacture WPCs, and there were no significant differences in their weathering properties during 500 h of xenon arc accelerated weathering.

Effects of UV, humidity, and high temperature exposure on linen fibers

Generally, the most common damaging factors for linen textile materials are the environmental conditions, their handling, and natural decay. Such environmental factors are ultraviolet (UV) radiation, humidity, and high temperature. Therefore, to investigate the effects these factors may cause, an accelerated weathering test was conducted on linen fabrics, using alternating cycles of UV exposure and humidity, along with relatively high temperatures. The effects of this test were investigated using non-destructive and micro-destructive analysis techniques. Scanning Electron Microscopy (SEM) was used to observe any modifications appearing at the surface of the fibers. Energy Dispersive X-Ray Analysis (EDS) was employed in conjunction with SEM for obtaining the spectrum of the chemical elements that were present at the surface of the linen samples. The modifications of functional groups occurring due to the weathering of linen were assessed by Fourier-Transform Infrared Spectroscopy (FT-IR). The color change of the samples was measured with a spectrophotometer. All the acquired information can be used as a starting point for the development of customized environmental parameters for keeping patrimony linen fabrics in museums in optimum conditions, thus preventing further damage. Additionally, the artificially weathered fabrics will be further employed in conservation experiments as substitute for old linen fabrics.

The effect of using alum mordant in wild cherry bark dyestuff for the production of UV resistant colored paper

Depending on the use of wood in the forest industry, wood bark is mostly peeled and used as fuel. The ash and smoke left from the burned bark causes environmental pollution. The most environmentally friendly method for waste disposal is to convert waste into a valuable commodity. In this study, cherry tree bark was used as a dyestuff in paper production. Wild cherry (Cerasus avium L.) bark was boiled with water and KOH. The purpose of using KOH is to increase the solubility of the bark compounds. The chemi-thermomechanical pulp (CTMP) was dyed using the dyestuff. The alum mordant is used to fi x the dyestuff. Paper can be exposed to external influences (mechanical, physical and biological) depending on the place of use. One of these effects is sunshine. When paper is exposed to direct or indirect sunlight, paper changes its color. Depending on the place of use, it is expected that the color of the paper will not be affected by the sunlight or that it will provide long-term strength after the application. Accelerated weathering test was chosen to measure the UV resistance of the dyestuff. The results have shown that the mordant has a significant effect on the fixation of dyestuff. After a total of 150 hours of weathering test, the color change was observed to be the lowest in the paper samples to which alum mordant was added to the dyestuff.

Potential of Advanced Consolidants for the Application on Sandstone

Alkoxy-based consolidants are widely used for conservation of cultural heritage objects made from sandstones. Even if such consolidants were introduced into practice already in the 19th century, their performance has been enhanced by several modifications to their composition only recently. To obtain a relevant comparison of their application potential, both commercial (Remmers KSE OH and SurfaPore FX SB) and a self-developed particle-modified ethyl silicate consolidant supplemented with two phosphate-based ones, were assessed. Importantly, the potential toxicity of our novel consolidants was considered. Since the stone substrate should mimic the properties of naturally weathered stone, sandstone from the Msene quarry in Central Bohemia, characterized by a high porosity and relatively low mechanical strength, is selected. From practical point of view, the long-term durability of the consolidation effect is crucial compared to the initial level of consolidation. Regarding the determination of durability of the sandstone consolidation according to an American Society for Testing and Materials (ASTM) accelerated weathering test, we performed mechanical tests in micro- (nanoindentation) and macroscale (drilling resistance measurements). The cohesion of the consolidant xerogels in the pores were determined by sorption experiments in gas phase. The durability of our TiO2 and ZnO particle-modified consolidants is superior to that of the commercial products. The aqueous diammonium hydrogen phosphate-based consolidant, which also shows exceptional durability, reveals itself to be a promising product for not only carbonate but also sandstone materials.