Toplinsko-mehanička analiza utjecaja nanočestica TiO2 na otpornost i stabilnost nanokompozita na bazi poliestera

master's thesis

• Title (english): Thermo-mechanical analysis of the effect of TiO2 nanoparticles on resistance and stability of polyester based nanocomposites
• Author: Tomislav Rodinger
• Mentor: Tatjana Haramina (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2015-07-16, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Zbog svoje velike površine u odnosu na volumen, nanočestice imaju drugačiji utjecaj na svojstva materijala matrice u usporedbi s istim dodacima većih dimenzija. U radu je provedena dinamičko-mehaničke analiza (DMA) nezasićenog poliestera s dodatkom nanočestica TiO2 na temperaturnom intervalu od sobne temperature do 125 °C, nakon čega su uzorci sporo ohlađeni na sobnu temperaturu. Na promatranom temperaturnom intervalu odvija se prijelaz iz staklastog u gumasto stanje pri čemu se modul smanji za dva reda veličine.

Uzorci su izloženi UV zračenju velikog intenziteta u trajanju od 5 i 15 min te se uz pomoć DMA analize pratila promjena modula elastičnosti i prijelaza iz staklasto u gumasto stanje uslijed strukturnih promjena nastalih zbog zračenja, kao i promjene nastale zbog sporog zagrijavanja i hlađenja tijekom DMA analize. Pokazalo se da se dodavanjem nanočestica u poliester smanjuje modul na cijelom temperaturnom intervalu, a najviše pri sobnoj temperaturi i to za 42%, a staklište pada za 25 °C. Svojstva kompozita mijenjaju se pod utjecajem UV zračenja i toplinske povijesti pri čemu rastu i modul i temperatura staklišta. Provedena su po tri sukcesivna mjerenja na neozračenim i ozračenim kompozitima pri čemu je primijećeno da je utjecaj prethodnog mjerenja velik kod drugog mjerenja, dok je kod trećeg ovaj utjecaj puno manji. Iz ovoga se zaključuje da nakon drugog zagrijavanja na 125 °C i sporog hlađenja dolazi do zasićenja.

Abstract (english)

Because of their large surface to volume ration, nanoparticles have a different effect on properties of matrix materials in comparison with the same additives of larger dimensions. In this thesis dynamic-mechanical analysis (DMA) of the unsaturated polyester with the addition of TiO2 nanoparticles was carried out in the temperature range from room temperature to 125 ° C, after which the samples were slowly cooled to room temperature. Within this temperature range the transition from a glassy to a rubbery state takes place in which the module is reduced by two orders of magnitude.

The samples were exposed to UV radiation of great intensity for 5 and 15 minutes and by means of DMA analysis the effects of heat and irradiation on modulus of elasticity and on the glass-to-rubbery transition were observed. The changes in the spectrum result from structural changes caused by radiation, as well as the slow heating and cooling during the DMA analysis. It has been shown that the addition of nanoparticles to the unsaturated polyester reduces the modulus at the whole temperature range and at room temperature it drops for 42 % whereas the glass transition temperature decreases for 25 °C. The properties of the composite can vary under the influence of UV radiation and thermal history in which the growth of the modulus and glass transition temperature was observed. Three successive measurements of the non-irradiated and irradiated composites were carried out wherein a large effect of the previous measurement was observed in the second measurement, while in the third run this effect is much lower. This leads to the conclusion that the second heating to 125 ° C and slow cooling leads to saturation.

• Keywords: dinamičko-mehanička analiza; TiO2 nanočestice; UV zračenje; toplinska povijest
• Keywords (english): Dynamic-Mechanical Analysis; TiO2 nanoparticles; UV radiation; thermal history
• Language: croatian
• URN:NBN: urn:nbn:hr:235:105056
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-05-22 13:41:05