Influence of temperature and humidity on aging tes

2022-08-23
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The influence of temperature and humidity on aging test in tape aging tester

I. The Influence of temperature on aging test in aging test chamber

because the effect of light is always accompanied by the rise of temperature, the rise of temperature is also an important factor to promote the aging of anti-corrosion coating. Generally, the heat of the anti-corrosion coating is aged by four vertical rods between the upper beam and the test bench, mainly due to the weight reduction process and the destruction of the polymer molecular chain; As a result of crosslinking, a three-dimensional structure is produced, which makes the anti-corrosion coating hard, brittle and inelastic; As a result of the molecular chain destruction, the macromolecular chain is broken. After the sample is clamped, the adjusting clamping force control valve and clamping speed control valve reduce the molecular length and molecular weight, forming free groups, which are soft and sticky. It is roughly estimated that if the temperature rises by 10 ℃, the speed of chemical reaction will be doubled. However, photochemical reaction is not usually a simple one-step reaction. The initial photochemical reaction is not affected by heat, and the second step reaction is affected by heat. Its effect is more important than simple thermal aging. In the artificial climate aging test, a certain temperature combined with periodic rainfall will cause frequent alternating temperature, because this will cause continuous expansion and contraction between the coating and the substrate, which can lead to the formation of great stress in the coating; In most cases, the system composed of anti-corrosion coating contains substances with different compositions and structures: primer, intermediate paint, color paint and finish paint. Therefore, when subjected to temperature alternation, due to the different stress in each coating, combined with strong light with a certain wavelength, it is easy to cause cracking of the anti-corrosion coating

II. The influence of humidity in the tape aging tester

exposed in the atmosphere, the anti-corrosion coating is actually kept in a wet state for a long time, especially in the humid tropics. The influence of moisture is also very complex, mainly including chemical reaction, physical effect, erosion, absorption/freezing thawing and thermal shock. Under high humidity conditions, water rapidly penetrates into the anti-corrosion coating, and the anti-corrosion coating will dissolve or swell due to the absorption of water. The city's financial system will seriously implement the decisions and arrangements of the central and municipal Party committees, and the volume will change, or the water-soluble substances in the anti-corrosion coating will be dissolved. When it is exposed to sunlight, especially ultraviolet light, its volume will expand rapidly, the structure will be damaged, or the photochemical change will be accelerated, It is easy to blister, rust and fall off. In particular, dew is rich in oxygen and stays on the coating surface for a long time than rain. The main reason for outdoor humidity is dew rather than rain

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