<p>U ovom radu, sintetisani su poli(uretan-izocijanuratni) elastomeri sa kovalentnim<br />čvorovima, katalitičkom ciklotrimerizacijom teleheličnih diizocijanata kao prekursora mreže<br />na osnovu 2,4-toluen-diizocijanata, α,ω-dihidroksipoli(oksipropilen)diola i monoola<br />dietilenglikolmonometiletra. Dobijeni su i termoplastični segmentirani poliuretani, sa<br />čvorovima fizičkog umreženja, jednostepenim postupkom i metodom prepolimerizacije,<br />reakcijom dve vrste alifatskog polikarbonatnog diola, koji se razlikuju u strukturi lanca,<br />heksametilen-diizocijanata i produživača lanca (1,4-butandiola). Sintetisana je i serija<br />poliuretanskih hibridnih materijala, dodatkom 1% <em>m/m</em> nanočestica organski modifikovanih<br />glina (montmorilonita i bentonita). Prioritet rada je bio da se utvrdi uticaj udela elastično<br />aktivnih i visećih lanaca na dinamičko-mehanička svojstva, toplotnu stabilnost i svojstva<br />prigušenja poliuretanskih mreža sa izocijanurat (heksahidro-1,3,5-triazin-2,4,6-trion)<br />prstenovima, kao čvorovima. Takođe, cilj istraživanja je bio da se ispita uticaj odnosa<br />reaktivnih grupa diizocijanata, polikarbonatne komponente i produživača lanca, kao i dodatka nanočestica na svojstva površine, morfologiju, dinamičko-mehanička i toplotna svojstva segmentiranih neojačanih i ojačanih elastomera. Toplotna degradacija poli(uretanizocijanuratnih) mreža i segmentiranih termoplastičnih poliuretana praćena je neizotermskim ispitivanjima, koristeći istovremenu termogravimetrijsku i masenu analizu (TG-MS), kao i istovremenu termogravimetriju i diferencijalno skenirajuću kalorimetriju (TG-DSC). Viskoelastična svojstva i svojstva prigušenja dobijenih poliuretanskih elastomera su ispitivana pomoću dinamičko-mehaničke analize (DMA). Toplotno ponašanje segmentiranih poliuretana i nanokompozita, dobijenih jednostepenim postupkom sinteze, je proučavano modulovanom diferencijalno skenirajućom kalorimetrijom (MDSC). Temperatura prelaska u staklasto stanje i termoplastična svojstva neojačanih i ojačanih poliuretanskih materijala, dobijenih postupkom prepolimerizacije, određeni su primenom diferencijalno skenirajuće kalorimetrije (DSC). Hemijska struktura i formiranje vodoničnih veza dobijenih elastomera proučavane su koristeći Furijeovu transmisionu infracrvenu spektroskopiju (FTIR). Uticaj udela tvrdih segmenata na morfologiju i svojstva površine segmentiranih poliuretana, ispitivan je pomoću mikroskopije atomskih sila (AFM). Stepen kristalnosti uzoraka i dispergovanje nanočestica u dobijenim hibridnim materijalima su odreñeni primenom metode rasipanja X-zraka pod širokim uglom (WAXS).</p> / <p> In this work, poly(urethane-isocyanurate) elastomers, with covalent junction points,<br /> were synthesized by catalytic cyclotrimerization of telechelic diisocyanates as network<br /> presursors based on 2.4-tolylenediisocyanate, a,w,dihydroxypoly(oxypropylene) and monool<br /> component 2-(2-metoxyetoxy)ethanol. Thermoplastic polyurethanes, with physical<br /> crosslinking, were obtained by one-step technique and pre-polimerization method, using two<br /> aliphatic polycarbonate diols (differening in chain constitution), hexamethylene-diisocyanate<br /> and chain extender (1,4-butane diol) as reactive components. One serie of polyurethane<br /> hybrid materials was prepared by addition of 1 wt. % of organically modified clay<br /> nanoparticles (bentonite and montmorillonite). The goal of this work was to investigate the<br /> influence of elastically active and dangling chains content on thermal stability, dynamic<br /> mechanical and damping properties of polyurethane networks with heat-resistant<br /> isocyanurate-(hexahydro-1,3,5-triazin-2,4,6-trion) rings, as crosslinks. The aim was also to<br /> determine the influence of diisocyanate, macrodiol and chain extender reactive groups’ ratio<br /> and nanoparticles addition on surface properties, morphology, dynamic mechanical and<br /> thermal properties of obtained segmented unfilled and filled elastomers. Thermal degradation<br /> of poly(urethane-isocyanurate) networks and segmented thermoplastic polycarbonate-based<br /> polyurethanes was investigated by nonisothermal analysis, using thermogravimetry coupled<br /> with mass spectroscopy analysis (TG-MS) and thermogravimetry coupled with differential<br /> scanning calorimetry (TG-DSC). Viscoelastic and damping properties of obtained<br /> polyurethane elastomers were estimated by dynamic mechanical measurements (DMA).<br /> Modulated differential calorimetry (MDSC) was used to investigate thermal behavior of<br /> segmented polyurethanes and nanocomposites, synthesized using one-step technique. The<br /> glass transition temperature and thermoplastic properties of unfilled and filled polyurethane<br /> materials, prepared by pre-polimerization procedure were assessed by differential scanning<br /> calorimetry (DSC). Fourier transform infrared spectroscopy (FTIR) was used to investigate<br /> the hydrogen bond formation and chemical structure of prepared segmented elastomers. The<br /> investigation of the influence of hard segment content on morphology and surface topography<br /> of prepared segmented elastomers sheets was done by atomic force microscope (AFM). In<br /> order to determine the degree of cristallinity and to evaluate the dispersion of<br /> montmorillonite and bentonite in the polyurethane matrices, the prepared hybrid materials<br /> were characterized by wide angle X-ray scattering (WAXS).</p>
| Identifer | oai:union.ndltd.org:uns.ac.rs/oai:CRISUNS:(BISIS)81933 |
| Date | 25 June 2010 |
| Creators | Pavličević Jelena |
| Contributors | Budinski-Simendić Jaroslava, Radičević Radmila, Stoiljković Dragoslav, Mesaroš Sečenji Katalin, Marinović-Cincović Milena |
| Publisher | Univerzitet u Novom Sadu, Tehnološki fakultet Novi Sad, University of Novi Sad, Faculty of Technology at Novi Sad |
| Source Sets | University of Novi Sad |
| Language | Serbian |
| Detected Language | English |
| Type | PhD thesis |
| Format | application/pdf |
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