The aim of this PhD project concerns the synthesis of a new class of cross-linking molecules for polymers used in the world of tires. In particular, these molecules must be stable at room temperature but capable of reacting thermally with the polymer matrix at temperatures greater than 100 ° C, forming irreversible covalent bonds. These functionalizers must also be simple to synthesize, integrable in an industrial process, versatile, economical, relatively low toxic and able to interact with the polymer without significantly affecting its properties. In this context, a system that is able to generate two reactive species in two different temperature ranges was created: the first functionality generates a carbene, the second a 1,3-dipolar species of the nitrilimino type. Both species are capable of providing cycloadducts with olefinic systems. After careful bibliographic research in order to identify the most suitable systems, both known and new compounds were synthesized, trying to modulate the activation temperature of these structures. All synthesized systems were characterized by NMR and IR analyzes. The characterization was completed by thermogravimetric analysis (TGA), with which the activation temperature of the functions present was detected; as well as the temperature at which the cycloaddition reaction should take place. Finally, on the most interesting selected systems, reactivity tests were performed on model polymeric systems that could be easily processed on a laboratory scale, in order to demonstrate the actual functionalization by thermal means. The molecules that presented the most interesting technological characteristics were prepared in quantities in the order of grams necessary to conduct compound tests using a "Brabander" mixer. These compounds were then analyzed by RPA (Rubber Process Analyzer) to observe any positive effects of the functionalized polymers. The system with two different activation temperatures was used to study possible effects on the morphology of the phases within polymeric blends: the different reactivity of the carbene and nitrilimine components is exploited, trying to improve the interaction of the two polymers as well as the physical properties of the resulting material. All compounds were also characterized by swelling, Dumbbell traction, DSC, DMA, frequency sweep and density.
Lo scopo di questo progetto di dottorato riguarda la sintesi di una nuova classe di molecole reticolanti per polimeri utilizzati nel mondo degli pneumatici. In particolare, queste molecole devono essere stabili a temperatura ambiente ma in grado reagire termicamente con la matrice polimerica a temperature maggiori di 100 °C, formando legami covalenti irreversibili. Questi funzionalizzanti devono essere anche semplici da sintetizzare, integrabili in un processo industriale, versatili, economici, relativamente poco tossici e in grado di interagire con il polimero senza però influenzarne significativamente le proprietà. In questo contesto è stato realizzato un sistema in grado di generare due specie reattive in due range di temperature diverse: la prima funzionalità genera un carbene, la seconda una specie 1,3-dipolare di tipo nitrilimminico. Entrambe le specie sono in grado di fornire cicloaddotti con sistemi olefinici. Dopo un’attenta ricerca bibliografica al fine di individuare i sistemi più adatti, sono stati sintetizzati sia composti noti in letteratura sia nuovi, cercando di modulare la temperatura di attivazione di queste strutture. Tutti i sistemi sintetizzati sono stati caratterizzati mediante analisi NMR e IR. La caratterizzazione è stata completata dall’analisi termogravimetrica (TGA), con la quale si è rilevata la temperatura di attivazione delle funzionalità presenti; nonchè la temperatura alla quale dovrebbe avvenire la reazione di cicloaddizione. Infine, sui sistemi più interessanti selezionati, sono state eseguite delle prove di reattività su sistemi polimerici modello e facilmente processabili su scala di laboratorio, al fine di dimostrare l’effettiva funzionalizzazione per via termica. Le molecole che presentavano caratteristiche tecnologiche più interessanti sono state preparate in quantità nell’ordine dei grammi necessari a condurre prove in mescola tramite un mini-mescolatore “Brabander”. Queste mescole sono state poi analizzate tramite RPA (Rubber Process Analyzer) per osservare eventuali effetti positivi dei polimeri funzionalizzati. Il sistema a due temperature di attivazione differenti è stato impiegato per studiare possibili effetti sulla morfologia delle fasi all’interno di blend polimerici: si sfrutta la diversa reattività delle componenti carbenica e nitrilimminica cercando di migliorare l’interazione dei due polimeri nonché le proprietà fisiche del materiale risultante. Tutti le mescole sono state caratterizzate anche tramite swelling, trazioni Dumbbell, DSC, DMA, frequency sweep e densità.
(2022). Multifunctionalized molecular systems for elastomers functionalization and as innovative crosslinkers in rubber compounds. (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2022).
Multifunctionalized molecular systems for elastomers functionalization and as innovative crosslinkers in rubber compounds
DE BELLIS, VITO
2022
Abstract
The aim of this PhD project concerns the synthesis of a new class of cross-linking molecules for polymers used in the world of tires. In particular, these molecules must be stable at room temperature but capable of reacting thermally with the polymer matrix at temperatures greater than 100 ° C, forming irreversible covalent bonds. These functionalizers must also be simple to synthesize, integrable in an industrial process, versatile, economical, relatively low toxic and able to interact with the polymer without significantly affecting its properties. In this context, a system that is able to generate two reactive species in two different temperature ranges was created: the first functionality generates a carbene, the second a 1,3-dipolar species of the nitrilimino type. Both species are capable of providing cycloadducts with olefinic systems. After careful bibliographic research in order to identify the most suitable systems, both known and new compounds were synthesized, trying to modulate the activation temperature of these structures. All synthesized systems were characterized by NMR and IR analyzes. The characterization was completed by thermogravimetric analysis (TGA), with which the activation temperature of the functions present was detected; as well as the temperature at which the cycloaddition reaction should take place. Finally, on the most interesting selected systems, reactivity tests were performed on model polymeric systems that could be easily processed on a laboratory scale, in order to demonstrate the actual functionalization by thermal means. The molecules that presented the most interesting technological characteristics were prepared in quantities in the order of grams necessary to conduct compound tests using a "Brabander" mixer. These compounds were then analyzed by RPA (Rubber Process Analyzer) to observe any positive effects of the functionalized polymers. The system with two different activation temperatures was used to study possible effects on the morphology of the phases within polymeric blends: the different reactivity of the carbene and nitrilimine components is exploited, trying to improve the interaction of the two polymers as well as the physical properties of the resulting material. All compounds were also characterized by swelling, Dumbbell traction, DSC, DMA, frequency sweep and density.File | Dimensione | Formato | |
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phd_unimib_846102.pdf
embargo fino al 14/04/2025
Descrizione: Multifunctionalized molecular systems for elastomers functionalization and as innovative crosslinkers in rubber compounds
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Doctoral thesis
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