Strukturiranje poliuretanskih materijala primenom različitih prekursora mreža
Structuring of polyurethane materials using different network precursors
Author
Pavličević, JelenaMentor
Budinski-Simendić, JaroslavaCommittee members
Radičević, RadmilaBudinski-Simendić, Jaroslava
Stoiljković, Dragoslav
Mesaroš-Sečenji, Katalin
Marinović-Cincović, Milena
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U ovom radu, sintetisani su poli(uretan-izocijanuratni) elastomeri sa kovalentnim čvorovima, katalitičkom ciklotrimerizacijom teleheličnih diizocijanata kao prekursora mreže na osnovu 2,4-toluen-diizocijanata, α,ω-dihidroksipoli(oksipropilen)diola i monoola dietilenglikolmonometiletra. Dobijeni su i termoplastični segmentirani poliuretani, sa čvorovima fizičkog umreženja, jednostepenim postupkom i metodom prepolimerizacije, reakcijom dve vrste alifatskog polikarbonatnog diola, koji se razlikuju u strukturi lanca, heksametilen-diizocijanata i produživača lanca (1,4-butandiola). Sintetisana je i serija poliuretanskih hibridnih materijala, dodatkom 1% m/m nanočestica organski modifikovanih glina (montmorilonita i bentonita). Prioritet rada je bio da se utvrdi uticaj udela elastično aktivnih i visećih lanaca na dinamičko-mehanička svojstva, toplotnu stabilnost i svojstva prigušenja poliuretanskih mreža sa izocijanurat (heksahidro-1,3,5-triazin-2,4,6-trion) prstenovima, kao čvorovima. Takođ...e, cilj istraživanja je bio da se ispita uticaj odnosa 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).
In this work, poly(urethane-isocyanurate) elastomers, with covalent junction points, were synthesized by catalytic cyclotrimerization of telechelic diisocyanates as network presursors based on 2.4-tolylenediisocyanate, a,w,dihydroxypoly(oxypropylene) and monool component 2-(2-metoxyetoxy)ethanol. Thermoplastic polyurethanes, with physical crosslinking, were obtained by one-step technique and pre-polimerization method, using two aliphatic polycarbonate diols (differening in chain constitution), hexamethylene-diisocyanate and chain extender (1,4-butane diol) as reactive components. One serie of polyurethane hybrid materials was prepared by addition of 1 wt. % of organically modified clay nanoparticles (bentonite and montmorillonite). The goal of this work was to investigate the influence of elastically active and dangling chains content on thermal stability, dynamic mechanical and damping properties of polyurethane networks with heat-resistant isocyanurate-(hexahydro-1,3,5-triazin-2,4,6-...trion) rings, as crosslinks. The aim was also to determine the influence of diisocyanate, macrodiol and chain extender reactive groups’ ratio and nanoparticles addition on surface properties, morphology, dynamic mechanical and thermal properties of obtained segmented unfilled and filled elastomers. Thermal degradation of poly(urethane-isocyanurate) networks and segmented thermoplastic polycarbonate-based polyurethanes was investigated by nonisothermal analysis, using thermogravimetry coupled with mass spectroscopy analysis (TG-MS) and thermogravimetry coupled with differential scanning calorimetry (TG-DSC). Viscoelastic and damping properties of obtained polyurethane elastomers were estimated by dynamic mechanical measurements (DMA). Modulated differential calorimetry (MDSC) was used to investigate thermal behavior of segmented polyurethanes and nanocomposites, synthesized using one-step technique. The glass transition temperature and thermoplastic properties of unfilled and filled polyurethane materials, prepared by pre-polimerization procedure were assessed by differential scanning calorimetry (DSC). Fourier transform infrared spectroscopy (FTIR) was used to investigate the hydrogen bond formation and chemical structure of prepared segmented elastomers. The investigation of the influence of hard segment content on morphology and surface topography of prepared segmented elastomers sheets was done by atomic force microscope (AFM). In order to determine the degree of cristallinity and to evaluate the dispersion of montmorillonite and bentonite in the polyurethane matrices, the prepared hybrid materials were characterized by wide angle X-ray scattering (WAXS).