Leioa, España
The study of new materials has led to the creation of smart materials. These materials can reversely change one of their property when are exposed to external stimulus. Inside this wide group, shape-memory polyurethanes can be found which possess shape-memory effect. Thanks to this effect, when they are exposure to a heat source their original shape is change into a temporary one. Once the new shape is achieved, the heat source is removed in order to fix them in the new shape. Finally, reheating again their original shape is recovered. In this work, shape-memory polyurethanes (SMPU) have been synthesised using poly(methyl ether)glycol, isophorone diisocyanate and hexamethylene diisocyanate, and castor oil and 1,4-butanediol as chain-extenders. Biocompatible SMPUs were achieved using natural origin castor oil reagent during the synthesis. All polyurethanes have been characterized using Fourier-transform infrared spectroscopy (FTIR), dynamic-mechanical analysis (DMA) and thermomechanical analysis (TMA) in order to know their physical-chemical features. FTIR technique was used for monitoring the reactions and to confirm that the isocyanate groups had completely reacted. DMA was used to know the glass transition temperature. It was check that decreasing the poliol molecular weight or increasing the stoichiometry value the glass-transition temperature value increases. Finally with TMA was evaluated that all synthesised polyurethanes had shape-memory effect. Polyurethanes can be applied in many application, thus, the objective has been the process of making biocompatible smart-textile. The process of getting textile started transforming the polymer into fibres. Due to this, electrospinning and extrusion techniques have been applied to process the fibres. Finally, fibres are woven to get textile using different methods.
Material berrien ikerketak material adimenduen sorkuntza ekarri du. Material horiek, modu itzulgarrian beren propietate bat edo gehiago aldatzeko gai dira kanpo estimulu baten eraginpean. Talde zabal honen barruan, forma-memoria poliuretanoak daude, zeinak forma-memoria efektua duten. Efektu honen bidez, poliuretanoak berotzean hasierako forma aldatzeko aukera dute; behin forma berrian izanda, hoztuz, forma berrian finkatzen dira; eta azkenik, birberotuz jatorrizko forma berreskuratzeko gaitasuna dute. Lan honetan forma-memoria poliuretanoak (SMPU) sintetizatu dira poli(tetrametilen) glikola, isoforona diisozianatoa eta hexametileno diisozianatoa erabiliz eta, kate-hedatzaile moduan errizino olioa eta 1,4-butanodiola erabiliz. SMPU biobateragarriak lortzeko, sintesian jatorri naturala duen errizino-olioa erabili da. Sintetizatu diren poliuretano guztiak Fourieren-transformatu bidezko espektroskopia infragorri (FTIR), analisi dinamiko-mekaniko (DMA) eta analisi termomekaniko (TMA) bidez karakterizatu dira propietate fisiko-kimikoak ezagutzeko. FTIR bidez erreakzioa monitorizatu da eta isozianato-taldeak guztiz erreakzionatu dutela ziurtatzeko erabili da. DMAren bidez beira-trantsizio tenperatura determinatu da, non, poliuretanoaren pisu molekularra txikitzean edo estekiometria balioa igotzean, beira-trantsizio tenperatura igotzen dela determinatu den. Azkenik TMA bidez, poliuretano guztiek memoria-forma dutela ziurtatu da. Poliuretanoak aplikazio anitzetan erabil daitezke; hala ere, helburua ehun biobateragarri adimendunak diseinatzea izan da. Ehunak egiteko, sintetizatzen diren polimerotik zuntzak lortu behar dira. Horretarako, zuntzak prestatzeko elektrobiraketa (electrospining) edo estrusio teknikak burutu dira. Azkenik, zuntzak ehotuz ehunak lortu dira, modu desberdinetan.
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