Title Struktura i svojstva PUR pjena Title (english) Structure and properties of PUR foams Author Valentina Šimatović Mentor Mirela Leskovac (mentor)Committee member Mirela Leskovac (predsjednik povjerenstva)Committee member Zvonimir Katančić (član povjerenstva)Committee member Petar Kassal (član povjerenstva)Granter University of Zagreb Defense date and country 2019-09-16, Croatia Scientific / art field, TECHNICAL SCIENCES Abstract Poliuretani nastaju reakcijom hidroksilne skupine poliola i izocijanatne skupine izocijanata, a naziv im je povezan s rezultirajućom uretanskom vezom. Njihova proizvodnja raste iz dana u dan, a najvažnija potrošnja poliuretana je u obliku pjene. Poliuretanska pjena ima ćelijastu strukturu, a prema krutosti može postojati kao kruta ili savitljiva pjena. Također, niska toplinska vodljivost čini poliuretansku pjenu izvrsnim toplinskim izolatorom krovova te hlađenih spremnika. U ovom radu dan je pregled dosadašnjih spoznaja o strukturi i svojstvima poliuretanskih pjenastih materijala. Osim teoretskih razmatranja, provedena su ispitivanja toplinskih svojstva i strukturna analiza četiri uzorka poliuretanske pjene: poliuretanske spužve za pranje posuđa (S-PP), medicinske poliuretanske spužve za pranje (S-MED), poliuretanske spužve za namještaj (S-N) i montažne PUR pjene (M-PUR). Strukturna analiza istražena je primjenom FTIR-ATR spektroskopije, a toplinska su svojstva istražena primjenom diferencijalne pretražne kalorimetrije (DSC) i termogravimetrijske analize (TGA). Provedena FTIR-ATR analiza potvrdila je prisutnost karakterističnih vrpci poliuretana u ispitivanim uzorcima. Također, kod uzoraka M-PUR i S-PP utvrđena je vrpca koja odgovara neizreagiranoj izocijanatnoj (-NCO) skupini, a što predstavlja opasnost za zdravlje ljudi i okoliš. Rezultati TGA analize ukazuju na nisku toplinsku stabilnost M-PUR pjene u odnosu na S-MED, S-PP i S-N pjene. Ostatak nakon razgradnje kod M-PUR, S-PP i S-N pjena posljedica je dodatka anorganske komponente, koja je vjerojatno punilo CaCO3. DSC analizom određene su temperature staklastog prijelaza i temperature taljenja mekog segmenta PUR pjena, dok talište i staklište tvrdog segmenta nije uočeno. Najmanju upojnost vode ima uzorak montažne PUR pjene (M-PUR) budući da u strukturi prevladavaju zatvorene ćelije koje otežavaju prodor vode u unutrašnjost. Dobiveni rezultati jasno ukazuju na važnost strukture i morfologije PUR pjena na toplinska svojstva i svojstva upojnosti vode.
Abstract (english) Polyurethanes, which represent one of the most important classes of polymers, are formed by the reaction between a hydroxyl group of polyols and an isocyanate group of isocyanates, and their name is associated with the resultant urethane bond. Their production is increasing day by day and the most important consumption of polyurethane is in the form of foam. Polyurethane foam has a cellular structure, and according to its rigidity, it can exist as a rigid or flexible foam. Low thermal conductivity makes polyurethane foam an excellent thermal insulator for roofs and refrigerated containers. This paper provides an overview of current knowledge about the structure and properties of polyurethane foam materials. In addition to theoretical considerations, thermal properties analysis and structural analysis of four samples of polyurethane foam (sponge) were performed: polyurethane dishwashing sponge (S-PP), polyurethane medical washing sponge (S-MED), polyurethane furniture sponge (S-N) and mounting PUR foams (M-PUR). Structural analysis was investigated by FTIR-ATR spectroscopy and thermal properties were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). FTIR-ATR analysis confirmed the presence of characteristic polyurethane bands in the samples. Also, for the M-PUR and S-PP samples, a band corresponding to the unreacted isocyanate (-NCO) group was identified, which causes a risk to human health and the environment. The results of TGA analysis indicate lower thermal stability for M-PUR foam, relative to S-MED, S-PP and S-N foams. The residue after thermal degradation of M-PUR, S-PP and S-N foams is due to the addition of an inorganic component, which is probably CaCO3 filler. The glass transition temperature and the melting temperature of the soft PUR foam segment were determined by DSC analysis, while the melting point and the glass temperature of hard segment were not observed. The sample of mounting PUR foam (M-PUR) has the lowest water absorption since closed cells dominates in the structure, which disable the penetration of water into the structure. The obtained results clearly indicate the importance of knowing the structure and morphology of PUR foams on the thermal and water absorption properties.
Keywords
poliuretan
poliuretanska pjena
strukturna svojstva
toplinska svojstva
Keywords (english)
polyurethane
polyurethane foam
structural properties
thermal properties
Language croatian URN:NBN urn:nbn:hr:149:557412 Study programme Title: Chemical Engineering - Undergraduate study Type of resource Text File origin Born digital Access conditions Access restricted to students and staff of home institution Terms of use Created on 2023-05-29 09:17:32
