20.500.12556/RUL-119516 Reverzibilno zamrežen poliuretan s pinakolno vezjo Reversibly crosslinked polyurethane with pinacol bond Namen naloge je predstaviti reverzibilno zamrežene poliuretane z aromatsko pinakolno enoto, ki vsebuje reverzibilno C-C vez. V obravnavani študiji so znanstveniki sintetizirali PU na osnovi pinakola (P1) ter za potrditev lastnosti P1 sintetizirali in testirali še podobne poliuretane (P2, P3), ki pa se med seboj razlikujejo v sestavi in po lastnostih. Visoko žilavost PU na osnovi pinakola pripisujejo visoki energiji C-C vezi, ki pada z dolžino vezi zaradi elektronskih in steričnih učinkov. V zmernih pogojih (primerna aktivacijska energija cepitve vezi) se vezi v PU na osnovi pinakola lahko razcepijo in znova povežejo. Mešanje in preurejanje mrež vodi v celjenje razpok. Temperatura steklastega prehoda poliuretana P1 je bila določena z dinamično mehansko analizo (DMA) preko izračuna modula (elastični E', viskozni E'') materiala in tan δ. Ugotovljeno je bilo, da za reverzibilno reakcijsko procesiranje P1 ni potrebna kontrola temperature. Najpomembnejši korak pri sintezi stimulativno odzivnega polimera P1 je bil predhodna sinteza hidroksi funkcionaliziranega aromatskega pinakola ter njegova vključitev v zamrežen poliuretan. The aim of the thesis is to present reversibly crosslinked polyurethanes with an aromatic pinacol unit containing a reversible C-C bond. In the study in question, the scientists synthesized PU based on pinacol (P1) and synthesized and tested similar polyurethanes (P2, P3) to confirm the properties of P1, but they differ in composition and properties. The high toughness of pinacol-based PUs is attributed to the high energy of the C-C bond, which decreases with bond length due to electronic and steric effects. Under moderate conditions (appropriate bond cleavage activation energy), the bonds in a pinacol-based PU can split and reconnect. Mixing and rearranging the nets leads to the healing of the cracks. The glass transition temperature of polyurethane P1 was determined by dynamic mechanical analysis (DMA) through the calculation of the modulus (elastic E', viscous E'') of the material and tan δ. It was found that no temperature control is required for reversible P1 reaction treatment. The most important step in the synthesis of the stimulus-responsive polymer P1 was the preliminary synthesis of hydroxy-functionalized aromatic pinacol and its incorporation into cross-linked polyurethane. polimer poliuretan zamrežen pinakolna vez polymer polyurethane crosslinked pinacol bond true false false Slovenski jezik Angleški jezik Diplomsko delo/naloga 2020-09-09 11:10:01 2020-09-09 11:10:07 2022-08-31 03:53:28 0000-00-00 00:00:00 2020 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 9041 28028163 Mihovec_Miha_-_Reverzibilno_zamrezen_poliuretan_s_pinakolno_vezjo.pdf Mihovec_Miha_-_Reverzibilno_zamrezen_poliuretan_s_pinakolno_vezjo.pdf 1 DA0ECA5CA429F0EA3FC4C1F1B58A56C4 9649bdc136f0ec7683ddf55cf252cde87d636f4f440b1d9fea63da917d972472 d9eab366-a1b9-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=134241 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0