Polisiloksanski gelovi s izabranim organskim otapalima i komponentama etanol-klorbenzenskoga dozimetrijskoga sustava

doctoral thesis

• Title (english): Polysiloxane gels with selected organic solvents and components of ethanol-chlorobenzene dosimetric system
• Author: Ivana Cetina
• Mentor: Danijela Ašperger (mentor)
• Mentor: Irina Pucić (mentor)
• Committee member: Emi Govorčin-Bajsić (predsjednik povjerenstva)
• Committee member: Vilko Mandić (član povjerenstva)
• Committee member: Tanja Jurkin (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2020-06-29, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry; Physical Chemistry
• Universal decimal classification (UDC): 54 - Chemistry. Crystallography. Mineralogy

Abstract

Za pripremu gelova na bazi polisiloksana odabrano je šest strukturno različitih alifatskih amina: bis(heksametilen)triamin (BHMTA), 1,3-diamino-2-propanol (DAP), dietilentriamin (DETA), tris(2-aminoetil)amin (TAEA), tetraetilenpentamin (TEPA) i trietilentetramin (TETA). Svi amini su reagirali s diglicidil-eter-terminiranim poli(dimetil-siloksanom) (PDMS-DGE) na relativno niskoj temperaturi od 50 ºC. U reakcijama bez prisutnosti tekuće komponente dobivene su stabilne prozirne gelne mreže. Gelovi različite stabilnosti dobiveni su dodavanjem odabrane tekuće komponente u reakcijski sustav. Za tekuće komponente odabrana su organska otapala s niskim vrelištima te njihove smjese, uključujući ECB dozimetrijsku otopinu. Odnos Hansenovih parametara topljivosti (HSP) tekućih komponenti i svojstava dobivenih gelnih mreža i gelova istražen je s različitim eksperimentalnim tehnikama. Rezultati ATR-FTIR i Raman spektroskopije dopunjeni su teorijskom vibracijskom analizom baziranom na teoriji funkcionala gustoće (DFT) kako bi se potvrdila točnost asignacije. U FTIR spektrima gelnih mreža apsorpcije primarnih i sekundarnih amina povezane su s dosegom reakcije pripreme kao i s promjenama nastalim djelovanjem gama-zračenja
(D = 50 kGy). Kombinacijom tih rezultata s onima Soxhlet ekstrakcije, bubrenja, toplinske analize (DSC), dielektrične spektroskopije i reoloških mjerenja pokazano je da je vrsta amina s kojim je provedena reakcija najviše utjecala na svojstva gelnih mreža i gelova na osnovi PDMS-a. Amini koji su mogli stvarati vodikove veze ili vezati više PDMS lanaca davali su gušće i stabilnije polimerne mreže. Iako su koncentracije tekućih komponenti u gelovima bile znatne (23 – 40 masenih %), na svojstva gelova je najviše utjecala vrsta amina. Stabilni i čvrsti gelovi priređeni su s onim tekućim komponentama čiji su Hansenovi parametri topljivosti slični onom od PDMS-a, bez obzira što te komponente nisu stvarale međumolekulske interakcije. Iako se očekivalo da će stvarati vodikove veze, gelovi koji su sadržavali alkohole bili su meki jer su Hansenovi parametri topljivosti alkohola značajno veći od onog PDMS-a. Neki od tih mekih gelova imali su svojstvo samoobnavljanja. Izlaganje gama-zračenju kod većine gelnih mreža i gelova uzrokovalo je samo neznatnu degradaciju. Stoga se može zaključiti da su gelne mreže i gelovi bazirani na PDMS-u priređeni niskotemperaturnom reakcijom s alifatskim aminima stabilni prema gama-zračenju najmanje do D = 50 kGy. To se također odnosi i na gelove koji su sadržavali ECB dozimetrijsku otopinu.

Abstract (english)

In order to prepare polysiloxane-based gels six structurally different amines were selected: bis(hexamethylene)triamine (BHMTA), 1,3-diamino-2-propanol (DAP), diethylenetriamine (DETA), tris(2-aminoethyl)amine (TAEA), tetraethylenepentamine (TEPA) and triethylenetetramine (TETA). All the amines reacted with diglycidyl ether terminated poly(dimethylsiloxane) (PDMS-DGE) at a relatively low temperature of 50 ºC. In reactions without a liquid component stable transparent gel-networks were obtained. Gels of various stability were prepared by adding a liquid component to reaction system. As liquid components low boiling point organic solvents and their mixtures including ECB dosimetric solution were selected. A number of analytical techniques were used to assess the relationship between Hansen solubility parameters (HSP) and gel properties. Results obtained by ATR-FTIR and Raman spectroscopies were complemented by theoretical vibration analysis based on density functional theory (DFT) to confirm the assignations. Primary and secondary amine absorptions in FTIR-spectra of gel-networks were correlated to preparation reaction extent and to the changes caused by gamma radiation (D = 50 kGy). By combining those results with the ones of Soxhlet extraction, swelling, thermal analysis (DSC), dielectric spectroscopy and rheological measurements it was shown that the amine reagent was the most important factor that determined the properties of studied PDMS-based gel-networks and gels. Amines that were able to form hydrogen bonds or to bond more PDMS chains produced denser and more stable networks. Although the concentration of liquid components in gels was significant (23 – 40 weight %), amine type still had the greatest impact on the gel properties. Stable and firm gels were produced with liquid components that had Hansen solubility parameters close to that of PDMS, regardless of the fact that these components did not form intermolecular interactions. Hansen solubility parameters of alcohols were higher than the one for PDMS so alcohols produced soft gels, although it was expected that hydrogen bonds will be formed. Some of those soft gels exhibited self-healing properties. Gamma irradiation caused slight degradation of most gel-networks and gels. Thus it may be concluded that low temperature amine cured PDMS-based gels, are stable to gamma irradiation at least to D = 50 kGy. The same applies to the gels containing ECB dosimetric solution.

• Keywords: polisiloksani; alifatski amini; niskotemperaturno umrežavanje; gelne mreže; kemijski gel; Hansenovi parametri topljivosti; teorija funkcionala gustoće; ionizirajuće zračenje; DSC; vibracijska spektroskopija; dielektrična spektroskopija; reološka mjerenja
• Keywords (english): polysiloxane; aliphatic amines; low temperature curing; gel-networks; chemical gel; Hansen solubility parameters; density functional theory; ionizing radiation; DSC; vibrational spectroscopy; dielectric spectroscopy; rheological measurements
• Language: croatian
• URN:NBN: urn:nbn:hr:149:024825
• Promotion: 2020
• Study programme: Title: Chemical Engineering and Applied Chemistry - Doctoral course; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija (doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija)
• Type of resource: Text
• Extent: 212 str. ; 30 cm
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2023-06-05 12:17:02