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The non-additivity of the substituent effect in para-, meta-, and ortho- homo-disubstituted benzenes on π-valence orbitals is smaller than that on σ-ones. The former increases while the latter decreases with π-electron-donating character of the substituent which demonstrates the role of hyperconjugation in the substituent effect.

The dynamic development of the automotive industry and improvements in quality of life have caused a significant increase in the production of car tires. Unfortunately, when the useful life of these products comes to an end, the problem of their disposal arises. The article presents the results of tests of epoxy mortars in which granules made from waste tires were used as a substitute for sand in the amount of 0, 20, 40, 60, 80 and 100% vol. respectively. The available literature lacks information about resin composites that arise with such a large or complete replacement of sand with rubber waste. Along with the increase in the content of waste, the values of strength parameters of composites decreased; however, a material characterized by very low water absorption, that is lightweight and with a low thermal conduction coefficient was obtained. Using the ADINA program, numerical simulations were carried out regarding the temperature distribution in a part of the building structure containing modified rubber mortar. The results of the simulation confirmed the possibility of practical use of the obtained composite due to its good thermal insulation properties. This approach to testing composites modified with rubber waste is innovative.

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