Utjecaj mikro i nanopunila na svojstva poliamida

master's thesis

• Title (english): The influence of micro and nano fillers on the polyamide properties
• Author: Ivan Grgurev
• Mentor: Mirela Leskovac (mentor)
• Committee member: Mirela Leskovac (predsjednik povjerenstva)
• Committee member: Lidija Furač (član povjerenstva)
• Committee member: Petar Kassal (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2019-09-27, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

U ovom radu istraživan je sustav PA 12 polimera (otpadni prah nakon 3D ispisa) i mikro-(staklene mikrosfere; mikro-SiO2) te nanopunila (Aerosil 200; nano-SiO2). Cilj ovog rada bio je utvrditi svojstva polimernih kompozita PA12/mikro-SiO2 i PA12/nano-SiO2, istražiti kakve su interakcije na međupovršini polimer/punilo primjenom metode kontaktnog kuta (određivanje slobodne površinske energije), kako količina i vrsta punila utječu na mehanizam popuštanja te na mehanička i toplinska svojstva kompozita primjenom diferencijalne pretražne kalorimetrije (DSC) i termogravimetrijske analize (TGA). Pripremljeni su kompoziti PA12/mikro-SiO2 i PA/nano-SiO2 različitih volumnih udjela punila: ϕ = 0,5 %, 1 %, 2 %, 3 %, 4 % i 5 %. Karakterizacija površine je provedena mjerenjem kontaktnog kuta te određivanjem parametara adhezije, a mehanička svojstva su određivana testom jednoosnog istezanja. Toplinska svojstva su određivana DSC i TGA metodama, dok je morfologija uzoraka je istražena skenirajućom elektronskom mikroskopijom (SEM). Rezultati mjerenja kontaktnog kuta ukazuju na hidrofobnost PA12 površine te hidrofilnost mikro- i nanopunila. Parametre optimalne adhezije zadovoljava sustav PA12(talina)/ mikro-SiO2. Rezultati provedene DSC analize ukazuju na to da se dodatkom mikro- i nanopunila u poliamidnu matricu temperatura staklastog prijelaza (Tg) neznatno povećava. Temperatura (Tm) i entalpija taljenja (ΔHm) se dodavanjem različitih udjela mikro- i nanopunila u poliamidnu matricu znatno ne mijenjaju. Kod pripremljenih nanokompozita, vidljiv je porast temperature kristalizacije (Tc), što znači da nanopunila djeluju kao heterogeni nukleacijski centri. Dobiveni rezultati provedene TGA analize ukazuju na to da se dodatkom mikro- i nanopunila u poliamidnu matricu toplinska stabilnost smanjuje, a posljedica toga je brža razgradnja mikro- i nanokompozita u odnosu na poliamidnu matricu. Rezultati SEM-a pokazali su da prevladava mehanizam odvajanja na međupovršini uslijed slabe adhezije mikropunilo-matrica.

Abstract (english)

In this study a system of PA12 polymer (leftover powder after 3D printing) with micro- (glass microsfere; micro-SiO2) and nano filler (Aerosil 200; nano-SiO2) was examined. The aim of this study was to determine the properties of polymer composites PA12/micro-SiO2 and PA12/nano-SiO2, to find out what are the interactions on the intersurface polymer/filler with applying the method of contact angle (determination of free surface energy), to find out how the amount and type of filler influence on the yielding mechanism and on mechanical and thermal properties of composites using the diferential scanning caloritmery (DSC) and thermogravimetric anlysis (TGA). The prepared composites were PA12/micro-SiO2 and PA/nano-SiO2 with different volume amount of fillers: ϕ = 0,5%, 1 %, 2.%, 3 %, 4 % and 5 %. Surface characterisation was determined by measurement of contact angle and calculation of adhesion parameters. Mechanical properties were determined by tensile test. Thermal properties were determined with DSC and TGA methods, while the samples morphology was examined with scanning electron microscopy (SEM). The results of measuring the contact angle showed that PA12 surface is hydrophobic, while micro- and nano filler surfaces are hydrophilic. The system PA12(melt)/micro-SiO2 had parameters of optimal adhesion. The results of DSC analysis showed that adding micro- and nano filler into PA matrix increase the temperature of glass transition, while temperature and entaplhy of melting remains the same. Regarding the temperature of crystalization, it is shown that nano fillers act like heterogenous nucleation centres. The results of TGA analysis showed that adding micro- and nano fillers to PA matrix reduce the thermal stability. SEM micrographs showed a mechanism of separation on intersurface caused by weak adhesion between micro filler/matrix.

• Keywords: poliamid; mikropunilo; nanopunilo; toplinska svojstva; mehanička svojstva
• Keywords (english): polyamide; microfiller; nanofiller; thermal properties; mechanical properties
• Language: croatian
• URN:NBN: urn:nbn:hr:149:701621
• Study programme: Title: Environmental Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka ekoinženjerstva (magistar/magistra inženjer/inženjerka ekoinženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2022-02-21 11:54:34