Photodegradation of Wuhan handern Polyethylene Profile Film
DATE：2020/4/29 8:08:20 / READ： / SOURCE：This station
Photodegradation of Wuhan handern Polyethylene Profile Film
Under the sunlight, the polyethylene shed film can absorb and reflect the solar radiation energy. The polyethylene shed film absorbs the energy of sunlight, making the molecules in polyethylene change from the original relatively stable ground state to the excited state; while the molecules in the excited state are extremely unstable, it will release the absorbed energy and release it. And back to the original base, this is the photophysical process of polymer (polyethylene). Due to the existence of the photophysical process, ultraviolet light, visible light, and infrared light in sunlight enter the greenhouse, generating a thermal effect, enabling plants to perform photosynthesis, etc. In addition, the photophysical process makes the photochemical reaction process of the polymer reduced Slow, play a certain role in protecting the material. www.handern.com Breathable membrane equipment
Sunlight, which can cause photochemical reactions (degradation), is the portion of light that can be effectively absorbed by the material. It causes the polymer (polyethylene) to produce excited molecules. The triplet oxygen (O2) excited by polyethylene after absorbing light energy can be transferred to the oxygen in the ground state through energy to generate singlet oxygen (O3). Because the singlet oxygen is extremely active, it reacts with the free radicals of polyethylene to generate peroxide radicals, which in turn seizes hydrogen to generate hydrogen peroxide and new polymer radicals. The chain reaction leads to the degradation of polyethylene. In fact, the occurrence of photochemical reaction (degradation) of polyethylene is mainly based on the following two aspects www.handern.com breathable membrane equipment
(1) There is an ultraviolet light absorbing group, which is derived from the polyethylene structure. There are groups in the chemical structure: unsaturated chains formed in the ethylene manufacturing process, transition metal ions in the residual catalyst, hydrogen peroxide and hydrogen peroxide generated by contact with oxygen Base compounds; polynuclear aromatic compounds, hydrogen peroxide compounds, etc. due to environmental pollution or oxygen in the air during the use of polyethylene shed films. www.handern.com Breathable membrane equipment
(2) There is ultraviolet light energy which comes from solar radiation. The sunlight reaching the earth's surface includes ultraviolet light, visible light, and infrared light. The larger the wavelength, the smaller the energy; the smaller the wavelength, the greater the energy. The external light only accounts for 5% of the solar radiation energy, but its wavelength is short, the energy is high, and it is the most destructive to polymers, and the ultraviolet light energy of different wavelengths is different. www.handern.com Breathable membrane equipment
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