Аннотация:Abstract—A series of poly[dimethyl(methylbenzyl)siloxanes] with different content of the methylbenzylsiloxanefragments have been synthesized. Structure of the polymers has been confirmed by means of 1Н and 29SiNMR spectroscopy. Thermal properties of the polymers have been investigated by means of differential scanningcalorimetry and thermogravimetric analysis. It has been found that the copolymer crystallization is suppressedat the content of the methylbenzylsiloxane fragments on the copolymer of 3 mol % and higher, whilethe glass transition temperature is only insignificantly shifted towards the positive range. The copolymershave exhibited high temperature resistance and can be used over a wide temperature range.FUNDINGInvestigation of the samples by means of NMR, GPC,and TGA was performed at the Collaborative Access Center“Сenter for Polymer Research” Enikolopov Institute ofSynthetic Polymeric Materials, Russian Academy of Sciencesand was supported by the Ministry of Science andHigher Education of the Russian Federation (topic no.FFSM-2021-0004).The study was financially supported by the Russian ScienceFoundation (project 21-73-30030).Synthesis of the monomers was financially supported by theGovernment of Tula region (Decree no. 899, December 30,2021) in the scope of Agreement no. 11, September 7, 2022.