ULTRAVIOLET PROTECTION AND DAMPING ABILITY OF TRANSPARENT POLYURETHANE MATRICES WITH THE COMPONENTS OF DIFFERENT CHEMICAL NATURE.

This article is devoted to the study of the influence of the chemical nature of the components of polyurethane matrices (PU) on their optical and viscoelastic properties in order to obtain polymer materials that combine several different functional properties: high transparency, effective UV protection and high damping ability. PU matrices with different chemical structures of diisocyanate (aliphatic (hexamethylene diisocyanate) or aromatic (toluylene diisocyanate)) and oligodiol (oligoether (oligooxypropylene glycol) or oligoester (oligodiethylene glycol adipate)) were synthesized. PU matrices with different molecular weights of ester (800 and 1500) were synthesized too. It was established that all PU matrices have a fairly high (~90 %) transmission coefficient in the range of visible wavelengths and UV blocking. However, the range of UV absorption significantly depends on the PU components. Matrices based on aliphatic diisocyanate absorb UV up to 250-280 nm. The UV absorption of PU matrices based on aromatic diisocyanate, regardless of the nature of their oligoester component and its molecular weight, undergoes a shift to the long-wavelength region - up to 300-400 nm, which is due to the presence of aromatic rings. For PUs with an aromatic component, the highest absorption in the UV region is observed for PUs based on oligoesters, which is explained by the greater absorption ability of ester groups relative to ether ones. It was found that PU matrix based on oligoester has better elastic properties, but the PU matrix based on oligoether is characterized by a wider temperature range of effective damping. The replacement of aliphatic diisocyanate with an aromatic one shift s the area of effective damping of PU material towards positive temperatures. Therefore, by changing the nature of PU components, as well as the molecular weight of the PU oligoester component, it is possible to obtain transparent materials with a wide temperature range of effective damping in combination with high protection against UV radiation. [ABSTRACT FROM AUTHOR]