Graphene has been getting much and much interest since its first successful preparation dating back to 2004. This discovery opened the doors to multiple applications of this newly available material ranging from electronics to composites to catalysts. The use of graphene as catalyst places new challenges such as its dispersion in a suitable media that makes it possible to preserve its nanoscale size, high surface area and its catalytic activity. Different methods have been developed throughout the years to change the solubility parameters of graphene in order to be able to disperse it more easily in different solvents. This thesis work focuses on the improvement of a self-assembled adduct of polymer and graphene to be used as nanoreactor for the synthesis of imines in water. Graphene sheets have been prepared through chemical exfoliation of high surface area graphite functionalized using serinol pyrrole (HSAG-SP) and of pristine high surface area graphite (HSAG). The exfoliation was conducted using three different block copolymers and one polyurethane based on 1,6-hexamethylene diisocyanate and serinol pyrrole. The block copolymers were synthesized through RAFT (reversible addition-fragmentation chain transfer) polymerization and have one end that provides good affinity with water and the other capable of non-covalently interaction with the graphene sheets in graphite. The synthesized polymers are all capable of binding to graphene forming nanoparticles in water. Their catalytic activity has been investigated and compared to the graphene and ethanol pyrrole-based polymer adducts used in the dropcat technology.
Sin dalla scoperta del primo processo di produzione di fogli di grafene, avvenuta nel 2004, questo materiale ha acquistato sempre più interesse da parte della comunità scientifica in particolare in applicazioni che riguardano l’elettronica, i materiali compositi e la catalisi. L’utilizzo del grafene come catalizzatore pone diverse sfide tra le quali la sua dispersione in un solvente adeguato che garantisca di preservare le sue dimensioni, la sua area superficiale e la sua attività catalitica. Durante gli anni sono stati sviluppati diversi metodi per modificare i parametri di solubilità del grafene per renderlo solubile in diversi solventi. Questa tesi si concentra nel miglioramento di un addotto polimero/grafene da usare come nanoreattore per la sintesi di immine in acqua. I fogli di grafene utilizzati derivano dall’esfoliazione chimica di grafite ad alta area superficiale funzionalizzata con serinol pirrolo (HSAG-SP) e grafite ad alta area superficiale pura (HSAG). L’esfoliazione è stata condotta utilizzando tre copolimeri e un poliuretano derivante da 1,6-esametilen diisocianato e serinol pirrolo. I copolimeri sono stati sintetizzati via polimerizzazione RAFT (reversible addition-fragmentation chain transfer) e possiedono una parte che offre buona affinità con acqua e l’altra capace di legarsi non covalentemente con i fogli di grafene nella grafite. I polimeri sintetizzati sono stati tutti capaci di legarsi ai fogli di grafene formando nanoparticelle in acqua. L’attività catalitica di questi addotti è stata investigata e confrontata con quella degli addotti di grafene e polimero basato su etanol pirrolo usato nella tecnologia dropcat.
Self-assembled adducts of polymers and graphene layers as confined spaces for organic reactions. The role of the polymers
VALENTINI, ENRICO
2018/2019
Abstract
Graphene has been getting much and much interest since its first successful preparation dating back to 2004. This discovery opened the doors to multiple applications of this newly available material ranging from electronics to composites to catalysts. The use of graphene as catalyst places new challenges such as its dispersion in a suitable media that makes it possible to preserve its nanoscale size, high surface area and its catalytic activity. Different methods have been developed throughout the years to change the solubility parameters of graphene in order to be able to disperse it more easily in different solvents. This thesis work focuses on the improvement of a self-assembled adduct of polymer and graphene to be used as nanoreactor for the synthesis of imines in water. Graphene sheets have been prepared through chemical exfoliation of high surface area graphite functionalized using serinol pyrrole (HSAG-SP) and of pristine high surface area graphite (HSAG). The exfoliation was conducted using three different block copolymers and one polyurethane based on 1,6-hexamethylene diisocyanate and serinol pyrrole. The block copolymers were synthesized through RAFT (reversible addition-fragmentation chain transfer) polymerization and have one end that provides good affinity with water and the other capable of non-covalently interaction with the graphene sheets in graphite. The synthesized polymers are all capable of binding to graphene forming nanoparticles in water. Their catalytic activity has been investigated and compared to the graphene and ethanol pyrrole-based polymer adducts used in the dropcat technology.| File | Dimensione | Formato | |
|---|---|---|---|
|
2019_12_Valentini.pdf
non accessibile
Descrizione: Enrico Valentini - Master's degree thesis - Chemical engineering
Dimensione
2.17 MB
Formato
Adobe PDF
|
2.17 MB | Adobe PDF | Visualizza/Apri |
I documenti in POLITesi sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
https://hdl.handle.net/10589/151243