Effect of ultraviolet and x-ray radiation on optical properties of epoxy polymers dyed with organic phosphors

Highly purified industrial bisphenols and cycloaliphatic epoxy oligomers from the ED - 24 and UP - 612 brands are used to produce optically clear products. Photodegradation was investigated using UV irradiation of a low pressure mercury lamp with 25% of light energy at 80% at 254 nm. To investigate the effect of X-rays on the spectrum of the organic dye in the epoxy polymer, an X-ray apparatus with a 0.7 BSV - Ag tube was used as the ionizing radiation source. A threshold for the energy produced by the ruby ​​laser is determined which shows degradation in the test sample recorded by the light scattering method to investigate the radiation resistance of the epoxy polymer. Basically, all dyes show high UV resistance. Observation of the absorption spectra shows that, on average, one-third of the dye molecules in the matrix will photobleach at 200 hours of exposure. The only exception is coumarin 1, which completely discolors after 40 hours of exposure. X-ray exposure of the sample for 2 hours resulted in a change in optical density equal to the change in optical density caused by exposure to UV radiation for 40 hours. However, in the first case the optical density of the substrate is proportional to the irradiation time and in the second case it remains stable during further UV irradiation. Comparison of photoageing processes in dyed and unstained epoxy polymers showed that the organic dyes studied do not sensitize the matrix. The stability of the optical properties of the epoxy matrix exposed to different factors was found to depend on the nature of the epoxy polymer and its manufacturing technique. The consequences of these effects differ markedly in the optical density change in the polymer and in the properties of the chemical conversion mechanism.

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Radiation-induced crosslinking processes in polymers are well known and have been used to improve the properties of some polymers such as polyethylene or polysulfone. However, high levels of radiation cause degradation of the polymer. An increase in hardness was observed after irradiation with gamma rays and UVA. In addition, gamma radiation is a widely used method for sterilizing polymer-based medical devices and prostheses. In some cases ultraviolet radiation (UVC) is also used to control the growth of bacteria, while ultraviolet radiation (UVA - UVB) from the sun is essentially an important cause of polymer degradation.

Ultraviolet light, a part of the electromagnetic spectrum from the violet or short wavelength end in the visible range to the X-ray region. The human eye can not detect ultraviolet (UV) light, but fluoresces when it hits a specific substance. That is, there is a possibility of emitting electromagnetic waves with low energy such as visible light. However, many insects can see ultraviolet rays. Ultraviolet rays are located between about 400 nm (1 nm × 10 -9 m) on the visible side and about 10 nm on the X-ray side, but in some authorities the limit of the short wavelength is expanded to 4 nm. In physics, ultraviolet rays are traditionally divided into four areas: near (400-300 nm), medium (300-200 nm), far (200-100 nm) and extreme (below 100 nm).