There are various methods for weather resistance testing. Below, we will mainly explain the principles of five types of weather resistance testing: heat resistance testing, wet heat testing, cold resistance testing, mold resistance testing, and salt spray testing.

1Heat resistance test

Heat is one of the main factors that promote the aging reaction of polymers. Heat can cause chain breakage of polymer molecules, resulting in the generation of free radicals and the formation of free radical chain reactions, leading to polymer degradation and cross-linking, and performance degradation. The oven aging test is a commonly used method for heat resistance testing. The sample is placed in a hot oven under selected conditions, and the appearance and performance changes of the sample are periodically inspected and tested to evaluate its heat resistance. This method is commonly used for plastics and rubber, and is also commonly used for heat resistance testing of information recording media.

IIDamp Heat Test

In the atmospheric environment, temperature (heat) and humidity (moisture) are objective factors. Some polymer materials are stored, transported, or used in high temperature and high humidity environments. Therefore, the wet heat aging test is a work with certain practical significance and economic value. Water vapor at high temperatures has a certain permeability to polymer materials. Under the action of heat, this permeability is stronger and can penetrate into the material system and accumulate to form water bubbles, thereby reducing intermolecular interactions and leading to material performance aging. The damp heat aging test generally uses a damp heat test chamber (constant temperature and humidity test chamber, high and low temperature damp heat test chamber), which can provide a standard pollution-free atmospheric environment.

IIIcold test

The cold resistance of polymers refers to their ability to resist performance changes caused by low temperatures, but when the ambient temperature reaches a certain low temperature range, the polymer will become brittle. Low temperature storage tests can identify the low-temperature storage characteristics of materials. Cold resistance is related to the chain movement of polymers, intermolecular forces, and chain flexibility. The main chain single bond of saturated polymers has good flexibility and cold resistance due to the absence of polar or steric hindrance substituents on the molecular chain. On the contrary, if the side group is a rigid substituent with high steric hindrance, or if the polymer is heavily crosslinked, its cold resistance will be poor.

4Anti mold test

Mold is a type of microorganism, and the excrement (organic acids) produced by mold metabolism can cause material failure. In order to evaluate the degree of mold growth in materials, artificial anti mold tests are usually used. The commonly used strains for mold testing include Aspergillus niger, Aspergillus flavus, Aspergillus niger, Penicillium, and Penicillium. Due to the different types of mold that can cause erosion and damage to different materials, different test strains should be selected for different polymer materials. The cycle of artificial anti mold test is 28 days. Currently, a mold aging test chamber is commonly used, which tests the antibacterial aging ability of polymer material products by cultivating fungi under certain temperature and humidity conditions.

5salt spray test

When the particles of salt spray settle and adhere to the surface of the material, they quickly absorb moisture and dissolve into an aqueous solution of chloride. Under certain temperature and humidity conditions, the chloride ions in the solution gradually penetrate into the interior through the micropores of the material, causing material aging or metal corrosion. Salt spray test is used to evaluate the electrochemical corrosion resistance of materials. The salt spray corrosion test chamber can detect the salt spray corrosion resistance of materials.

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