doktorska disertacija
Alenka Bunderšek (Author), Peter Krajnc (Mentor)

Abstract

V pričujočem delu sem se ukvarjala z vgradnjo ATH nanodelcev v akrilne sisteme. Nanodelci so bili sintetizirani po sol-gel postopku na Nanotesla Institutu v Ljubljani. Za karakterizacijo delcev smo uporabili različne metode. Velikost delcev smo določili z BET metodo, porazdelitev in velikost z DLS, sestavo smo proučili z XRD. Preliminarne raziskave so pokazale, da je nemogoče pripraviti utrjene nanokompozitne plošče in hkrati ohranili transmisijo PMMA, z neposrednim vnosom ATH koloida v akrilatno vezivo, pripravljeno iz MMA. Zaradi večje kompatibilnosti polimerne matrice in polnila, smo ATH nanodelce integrirali v hidrofilna veziva, izdelana iz monomerov, ki so vsebovali hidroksilno skupino. Iz HEMA, HEA in HPA monomerov smo z radikalsko polimerizacijo v 2-propanolu sintetizirali omenjena hidrofilna veziva z različnimi stopnjami konverzije, ki smo jo zasledovali z metodo določanja suhe snovi. Iz ATH koloida, hidrofilnih veziv in dodatkov smo izdelali predpolimerizacijske mešanice, ki so se med sabo razlikovale glede na uporabljeno hidrofilno vezivo in na vsebnost suhe snovi v vezivu. V naslednji fazi smo prav tako z radikalsko polimerizacijo MMA izdelali akrilno vezivo, z 20 ± 5 % vsebnostjo suhe snovi. Iz izdelanega akrilnega veziva in predpolimerizacijske mešanice smo pripravili utrjene akrilne nanokompozite v obliki 3 ± 0,2 mm ploščic. Ugotovili smo, da nanodelci upočasnjujejo hitrost polimerizacije. Izdelali smo plošče z 5 ut. % in 10 ut. % predpolimerizacijske mešanice. Nanokompozitnim ploščam smo določili mehanske, termične in optične lastnosti, ter testirali njihovo odpornost na ogenj. Ugotovili smo, da je na lastnosti utrjenih nanokompozitov vplivala tako koncentracija predpolimerizacijske mešanice, kot tudi vezivo, ki smo ga uporabili za izdelavo le-te. Izdelani nanokompoziti so bili različno odporni na ogenj. Pri spremljanju hitrosti gorenja smo opazili, da so vzorci, ki so vsebovali predpolimerizacijsko mešanico izdelano s HEMA hidrofilnim vezivom goreli počasneje. V okviru disertacije smo proučevali tudi sinergijske učinke nanodelcev ATH s komercialno dosegljivim TEP. Plošče izdelane z obema dodatkoma so v primerjavi z vzorci, ki so vsebovale le ATH nanodelce pokazale večjo odpornost na ogenj. Vzorci so goreli z zmanjšano hitrostjo ali pa so celo ugasnili. Poleg samega gorenja, ki predstavlja neposredno nevarnost, med gorenjem nastajajo tudi toksični plini, ki predstavljajo nevarnost za človeka in okolje. Zato smo se odločili in v okviru disertacije izmerili koncentracijo plina CO2 in CO med gorenjem vzorcev, ki sta izkazala največjo odpornost na ogenj. Testiranje je pokazalo, da nanodelci ATH in TEP vplivajo tako na hitrost gorenja, kot tudi na količino nastalih toksičnih plinov. V primeru uporabe omenjenih dodatkov so bile vrednosti merjenih plinov nižje. Vzorec, ki je vseboval nanodelce ATH in TEP, je med samim testiranjem celo ugasnil.

Keywords

nanokompoziti;polimetilmetakrilat;nanodelci;akrilni kompoziti;ognjeodpornost;mehanske lastnosti;aluminijev trihidroksid;doktorske disertacije;Polimerni materiali;Disertacije;PMMA;Izboljšanje odpornosti;

Data

Language: Slovenian
Year of publishing:
Typology: 2.08 - Doctoral Dissertation
Organization: UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher: [A. Bunderšek]
UDC: 620.3:678.744.33.017(043.3)
COBISS: 280318464 Link will open in a new window
Views: 1450
Downloads: 192
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Other data

Secondary language: English
Secondary title: INFLUENCE OF INTEGRATION OF Al(OH)3 NANOPARTICLES ON PROPERTIES OF CURED ACRYLIC COMPOSITES
Secondary abstract: Present work describes the integration of ATH nanoparticles into acrylic systems. Nanoparticles were synthesized by sol-gel procedure at the Nanotesla Institute Ljubljana. For particle characterization different methods were used. Particle size and distribution were determined using BET method and dynamic light scattering, crystallographic structures were examined by X-ray diffraction. Preliminary study clearly demonstrated that it was impossible to prepare PMMA nanocomposite sheets with integrated ATH nanoparticles while at the same time retaining the transparency of pure PMMA. To achieve better compatibility of nanoparticles and polymer matrix, ATH nanoparticles were firstly integrated into hydrophilic acrylic resin made of monomers with a hydroxyl group. From HEMA, HEA and HPA monomers during the radical polymerization in 2-propanol, hydrophilic acrylic resins with different conversions were made. The degree of conversion was followed by determination of non-volatile matter. ATH colloid, hydrophilic acrylic resin and additives were used to prepare premixes, which differed in type of used hydrophilic acrylic resin and in the degree of non-volatile matter of resin. Furthermore, during MMA polymerization, PMMA acrylic resin with 20 ± 5 % of dry matter was prepared. PMMA resin and premixes were used for the preparation of 3 mm nanocomposite sheets. Nanocomposite sheets with 5 wt. % and 10 wt. % of premix were made. Temperature and rate of polymerization were followed by temperature sensors. Integration of nanoparticles showed negative effect on the rate of polymerization. Mechanical, thermal and optical properties of cured sheets were measured and resistance to fire was tested. We have found that the properties of the nanocomposite sheets are affected both the concentration of the premix and the hydrophilic acrylic resin which was used for the manufacture thereof. During the measurements of the rate of burning it was observed that the samples containing premix manufactured with HEMA acrylic resin burned slower. As a part of the thesis we have also studied the synergistic effects of nanoparticles ATH with commercially available TEP. Nanocomposite sheets made with both additives, compared with samples that contained only ATH nanoparticles showed better resistance to fire. These samples burned at low speed or even stopped burning. Besides fire, which poses an immediate danger, toxic gases are also produced during combustion and pose a threat to human health and environment. We measured the concentration of CO2 and CO during combustion of samples that showed the greatest resistance to fire. Testing showed that nanoparticles ATH and TEP affect both the combustion and the formation of toxic gases. The sample which contained ATH and TEP nanoparticles even extinguished during the testing.
Secondary keywords: nanocomposites;nanoparticles;polymethyl metacrylate;aluminium hydroxide;fire resistance;
URN: URN:SI:UM:
Type (COBISS): Dissertation
Thesis comment: Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages: XIV, 125 str.
ID: 8757042