scholarly journals A durable coating to prevent stress corrosion effects on the surface strength of annealed glass

2021 ◽  
Author(s):  
Gregorio Mariggiò ◽  
Sara Dalle Vacche ◽  
Roberta Bongiovanni ◽  
Christian Louter ◽  
Mauro Corrado
Keyword(s):  
Cyclic Loading ◽  
Stress Corrosion ◽  
Bending Strength ◽  
Natural Weathering ◽  
Ring Test ◽  
Polymeric Coating ◽  
Surface Strength ◽  
Artificial Weathering ◽  
Double Ring ◽  
Annealed Glass

AbstractThe durability of an innovative polymeric coating recently developed by the authors to prevent stress corrosion in annealed glass is herein examined. The coating, having functional graded properties through the thickness, is optimised to provide a very good adhesion with glass and an excellent hydrophobic behavior on the side exposed to the environment, thus creating a good barrier to humidity, which is the triggering agent for stress corrosion. Three scenarios are analysed in terms of ageing: (i) cyclic loading, accomplished by subjecting coated samples to repetitive loading; (ii) natural weathering, performed by exposing coated samples to atmospheric agents; (iii) artificial weathering, carried out by exposing coated specimens to fluorescent UV lamps, heat and water. The durability of the coating is assessed indirectly, on the base of its residual effectiveness in preventing stress corrosion, by comparing the bending strength, obtained with the coaxial double ring test, of aged coated glass specimens with that of un-coated and freshly coated specimens. The obtained results prove that the proposed formulation is almost insensitive to cyclic loading, maintains a very good performance in case of natural weathering, whereas is slightly more sensitive to artificial weathering.

scholarly journals Mechanical performance of wood under artificial and natural weathering treatments

BioResources ◽  
2019 ◽  
Vol 14 (3) ◽  
pp. 6267-6277
Keyword(s):  
Exposure Time ◽  
Modulus Of Elasticity ◽  
Elastic Limit ◽  
Bending Strength ◽  
Mechanical Performance ◽  
General Information ◽  
Bending Test ◽  
Natural Weathering ◽  
Linear Regression Models ◽  
Artificial Weathering

Natural and artificial weathering treatments were studied to determine the change of wood properties as a function of exposure time. This paper aimed to provide general information about the mechanical performance of wood under natural and artificial weathering treatments and define a relationship between them. The eight strength classes of ABNT NBR 7190 (1997) were considered, in addition to a paired sampling approach. The modulus of elasticity and conventional strength value in static bending, strength in compression parallel to the grain, hardness perpendicular to the grain, and the elastic limit in the static bending test were investigated. Linear regression models for mechanical performances under artificial and natural aging treatments of the exposure time were made and tested using an analysis of variance. According to the results, 360 days of natural weathering provoked a change in mechanical performance of 15.72% that included a decrease in strength and modulus of elasticity and an increase in elastic limit. Twelve hours of the artificial weathering treatment provided the effect of 6.22 days of natural weathering exposure.

scholarly journals Durability of Wood Exposed to Alternating Climate Test and Natural Weathering

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 953
Author(s):  
Alexander Stadlmann ◽  
Maximilian Pramreiter ◽  
Robert Stingl ◽  
Christian Kurzböck ◽  
Thomas Jost ◽  
...  
Keyword(s):  
Bending Strength ◽  
Accelerated Aging ◽  
Climatic Conditions ◽  
Natural Weathering ◽  
Nacl Solution ◽  
Artificial Weathering ◽  
Hygroscopic Properties ◽  
Concentration Changes ◽  
Penetration Behavior ◽  
Effects Of Media

The use of wood-based materials in the automotive industry is currently under discussion and investigation. One of the major material requirements for such applications is sufficient weathering stability. This can be demonstrated by an accelerated aging process in which the samples are exposed to changing climatic conditions and a spray mist of an aqueous NaCl solution. The effects of media salt (NaCl) on the mechanical and physical properties of wood have scarcely been investigated. The presented study investigated the changes in bending strength (MOR), modulus of elasticity (MOE), and impact bending strength (α) of naturally and artificially weathered oak (Quercus spp.) and birch (Betula pendula Roth) wood. The tests provided comparable results. The decrease under natural weathering of oak was 3.73%, 4.69%, and 6.45% for MOR, MOE, and α. Under artificial weathering the decrease observed for oak was 7.33%, 10.87%, and 16.29% and 3.2%, 8.21%, and 4.03% for birch respectively. It is remarkable that α increased for birch wood at the beginning of the artificial weathering cycles. The penetration of the aqueous NaCl solution into the wood substance resulted in an increase in the wood’s equilibrium moisture content (EMC), which can be explained by the stronger hygroscopic properties of NaCl compared to wood. The higher impact strength at the beginning of artificial weathering can be partly explained by this increase in EMC. In order to investigate the penetration behavior of salt into the wood substrate, the artificially weathered samples were examined by means of energy dispersive X-ray analysis (EDX) and it was shown that the salt concentration changes significantly over the weathering cycles and sample cross-section.

Comparison of wood coating durability in natural weathering and artificial weathering using fluorescent UV-lamps and water

2014 ◽  
Vol 72 (3) ◽  
pp. 367-376 ◽  
Author(s):  
Gerhard Grüll ◽  
Florian Tscherne ◽  
Irene Spitaler ◽  
Boris Forsthuber
Keyword(s):  
Natural Weathering ◽  
Wood Coating ◽  
Artificial Weathering ◽  
Coating Durability ◽  
Uv Lamps

scholarly journals Influence of Natural and Artificial Weathering on the Colour Change of Different Wood and Wood-Based Materials

Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 488 ◽  
Author(s):  
Davor Kržišnik ◽  
Boštjan Lesar ◽  
Nejc Thaler ◽  
Miha Humar
Keyword(s):  
Laboratory Test ◽  
Colour Change ◽  
Natural Weathering ◽  
Blue Staining ◽  
Artificial Weathering ◽  
Blue Stain Fungi ◽  
Colour Changes ◽  
Blue Stain ◽  
Positive Correlations ◽  
The Aesthetic

The importance of the aesthetic performance of wood is increasing and the colour is one of the most important parameters of aesthetics, hence the colour stability of twelve different wood-based materials was evaluated by several in-service and laboratory tests. The wood used for wooden façades and decking belongs to a group of severely exposed surfaces. Discolouration of wood in such applications is a long-known phenomenon, which is a result of different biotic and abiotic causes. The ongoing in-service trial started in October 2013, whilst a laboratory test mimicking seasonal exposure was performed in parallel. Samples were exposed to blue stain fungi (Aureobasidium pullulans and Dothichiza pithyophila) in a laboratory test according to the EN 152 procedure. Afterwards, the same samples were artificially weathered and re-exposed to the same blue stain fungi for the second time. The purpose of this experiment was to investigate the synergistic effect of weathering and staining. The broader aim of the study was to determine the correlation factors between artificial and natural weathering and to compare laboratory and field test data of fungal disfigurement of various bio-based materials. During the four years of exposure, the most prominent colour changes were determined on decking. Respective changes on the façade elements were significantly less prominent, being the lest evident on the south and east façade. The results showed that there are positive correlations between natural weathering and the combination of artificial weathering and blue staining. Hence, the artificial weathering of wood-based materials in the laboratory should consist of two steps, blue staining and artificial weathering, in order to simulate colour changes.

scholarly journals Half-threaded holes markedly increase the fatigue life of locking plates without compromising screw stability

2020 ◽  
Vol 9 (10) ◽  
pp. 645-652
Author(s):  
Ching-Kong Chao ◽  
You-Lin Chen ◽  
Jinn Lin
Keyword(s):  
Fatigue Life ◽  
Cyclic Loading ◽  
Bending Strength ◽  
Locking Plates ◽  
Titanium Plate ◽  
Plate Design ◽  
American Society ◽  
Future Work ◽  
Mechanical Strengths ◽  
The Relationship

Aims To determine whether half-threaded screw holes in a new titanium locking plate design can substantially decrease the notch effects of the threads and increase the plate fatigue life. Methods Three types (I to III) of titanium locking plates were fabricated to simulate plates used in the femur, tibia, and forearm. Two copies of each were fabricated using full- and half-threaded screw holes (called A and B, respectively). The mechanical strengths of the plates were evaluated according to the American Society for Testing and Materials (ASTM) F382-14, and the screw stability was assessed by measuring the screw removal torque and bending strength. Results The B plates had fatigue lives 11- to 16-times higher than those of the A plates. Before cyclic loading, the screw removal torques were all higher than the insertion torques. However, after cyclic loading, the removal torques were similar to or slightly lower than the insertion torques (0% to 17.3%), although those of the B plates were higher than those of the A plates for all except the type III plates (101%, 109.8%, and 93.8% for types I, II, and III, respectively). The bending strengths of the screws were not significantly different between the A and B plates for any of the types. Conclusion Removing half of the threads from the screw holes markedly increased the fatigue life of the locking plates while preserving the tightness of the screw heads and the bending strength of the locking screws. However, future work is necessary to determine the relationship between the notch sensitivity properties and titanium plate design. Cite this article: Bone Joint Res 2020;9(10):645–652.

scholarly journals Compositionally Graded Hydrophobic UV-Cured Coatings for the Prevention of Glass Stress Corrosion

Coatings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 424 ◽  
Author(s):  
Sara Dalle Vacche ◽  
Gregorio Mariggiò ◽  
Alessandra Vitale ◽  
Roberta Bongiovanni ◽  
Mauro Corrado
Keyword(s):  
Tensile Strength ◽  
Stress Corrosion ◽  
Mechanical Load ◽  
Load Test ◽  
Good Adhesion ◽  
Compositional Profile ◽  
Double Ring ◽  
Structural Applications ◽  
Graded Coating ◽  
Set Up

The use of glass in architecture is growing and is moving towards structural applications. However, the tensile strength of glass cannot be fully exploited because of stress corrosion. This is a corrosion triggered by stress applied to the material and dependent on environmental factors such as humidity and temperature. To protect glass from stress corrosion, we developed a UV-cured coating, characterized by hydrophobicity, barrier to water vapor properties, and good adhesion to glass, thanks to a compositional profile. The coating was obtained by combining a cycloaliphatic diacrylate resin with a very low amount of a perfluoropolyether methacrylate co-monomer, which migrated to the free surface, creating a compositionally graded coating. The adhesion to glass was improved, using as a primer an acrylated silane able to co-react with the resins. With a mechanical load test using the coaxial double ring set-up, we proved that the coating is effective in the inhibition of stress corrosion of glass plates, with an increase of 76% of tensile strength.

Glass Fiber Stress-Corrosion Setup: Selection of a Polymeric Coating Material for the Pushing Rod

2020 ◽  
Author(s):  
Andrejs Krauklis
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Glass Fiber ◽  
Stress Corrosion ◽  
Polymeric Coating ◽  
Fiber Stress ◽  
Coating Materials ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
Selection Of

Various polymers were tested for leaching of ions via High Resolution Induced Coupled Plasma Mass Spectrometry (HR-ICP-MS) in order to determine which coating materials for the pushing rod are compatible with the glass fiber stress-corrosion setup. The biggest concern is the leaching of Si ions, and is compared among various commercially available polymers - four different polyurethanes, polyvinylchloride, poly(methylmethacrylate) and silicone. Significant amounts of other elements leached were also noted and reported.

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