This manuscript presents the studies conducted on the scalability of the radical polymerization of styrene using the atom transfer technique with activators regenerated by electron transfer (ARGET ATRP) from chlorinated initiators. Building on the research group's existing knowledge of the ascorbic acid/sodium carbonate reactivation system, a new one consisting of a lipophilic ascorbic acid derivative in combination with organic bases was studied. This resulted in a homogeneous polymerization system on which it was possible to study the impact of the pKa of the organic base on the molecular weight and polydispersity of the polymers produced, as well as the influence of the presence of trace amounts of water and oxygen on the process. This approach also allowed the reaction to be scaled up, making it possible to produce halogen-terminated polystyrene samples in quantities of tens of grams. Various post-functionalization reactions were then conducted on the obtained telechelic substrates in order to obtain polystyrenes with various reactive chain-ends (hydroxide, thiol, epoxide, azide, amino). Although many of these reactions are already documented in the literature, the primary objective of these studies has been to expand the repertoire of reactions that can be performed on chlorine-terminated polystyrenes, which are generally neglected in comparison with bromine-terminated substrates, by simplifying and adapting synthetic procedures to facilitate their industrial implementation. The functionalized polymers thus obtained may constitute an interesting new class of crosslinking agents, applicable in both conventional and dynamic networks, characterized by tunable properties. In parallel to these experiments, studies are also presented on the kinetics of anomalous crosslinking observed during ARGET ATRP of styrene from bifunctional initiators, the kinetics of ARGET ATRP of sodium styrene sulfonate, the use of different solvent/catalyst pairs as well as the synthesis and use of a new class of bifunctional initiators for ARGET ATRP aimed at obtaining thermostable polystyrenes.
Questo elaborato illustra gli studi condotti sulla scalabilità della polimerizzazione radicalica dello stirene utilizzando la tecnica a trasferimento di atomo con attivatori rigenerati tramite trasferimento elettronico (ARGET ATRP) a partire da iniziatori clorurati. Forti dalle conoscenze già acquisite dal gruppo di ricerca sul sistema rigenerante acido ascorbico/sodio carbonato, se ne è studiato uno nuovo costituito da un derivato lipofilo dell’acido ascorbico in combinazione con basi organiche. Ciò ha permesso di ottenere un sistema omogeneo di polimerizzazione sul quale è stato possibile studiare l’impatto del pKa della base organica sul peso molecolare e sulla polidispersità dei polimeri prodotti, nonchè l’influenza della presenza di tracce di acqua e ossigeno sul processo. Questo approccio ha inoltre permesso di scalare la reazione, consentendo di produrre campioni di polistirene alogeno-terminato in quantità di decine di grammi. Sui substrati telechelici ottenuti sono poi state ottimizzate diverse reazioni di post-funzionalizzazione al fine di ottenere polistireni con varie terminazioni reattive (idrossido, tiolo, epossido, azide, ammino). Sebbene molte di queste reazioni siano già documentate in letteratura, l’obiettivo primario di questi studi è stato quello di ampliare il repertorio di reazioni eseguibili sui polistireni cloro-terminati, generalmente trascurati rispetto ai substrati bromo-terminati, semplificando e adattando le procedure sintetiche per facilitarne l'implementazione industriale. I polimeri funzionalizzati così ottenuti possono costituire una nuova interessante classe di agenti reticolanti, applicabili sia in reticoli convenzionali che dinamici, caratterizzati da proprietà modulabili. In parallelo a questi studi, vengono inoltre presentati studi sulle cinetiche della reticolazione anomala osservata durante l’ARGET ATRP dello stirene da iniziatori bifunzionali, sulla cinetica dell’ARGET ATRP dello stirene solfonato di sodio, sull’utilizzo di diverse coppie solvente/catalizzatore nonchè sulla sintesi e l’utilizzo di una nuova classe di iniziatori bifunzionali per l’ARGET ATRP volta all’ottenimento di polistireni termostabili.
ARGET ATRP scalabile dello stirene: studi sul crosslinking e post-funzionalizzazione / Niccolo' Braidi , 2024 May 08. 36. ciclo, Anno Accademico 2022/2023.
ARGET ATRP scalabile dello stirene: studi sul crosslinking e post-funzionalizzazione
BRAIDI, NICCOLO'
2024
Abstract
This manuscript presents the studies conducted on the scalability of the radical polymerization of styrene using the atom transfer technique with activators regenerated by electron transfer (ARGET ATRP) from chlorinated initiators. Building on the research group's existing knowledge of the ascorbic acid/sodium carbonate reactivation system, a new one consisting of a lipophilic ascorbic acid derivative in combination with organic bases was studied. This resulted in a homogeneous polymerization system on which it was possible to study the impact of the pKa of the organic base on the molecular weight and polydispersity of the polymers produced, as well as the influence of the presence of trace amounts of water and oxygen on the process. This approach also allowed the reaction to be scaled up, making it possible to produce halogen-terminated polystyrene samples in quantities of tens of grams. Various post-functionalization reactions were then conducted on the obtained telechelic substrates in order to obtain polystyrenes with various reactive chain-ends (hydroxide, thiol, epoxide, azide, amino). Although many of these reactions are already documented in the literature, the primary objective of these studies has been to expand the repertoire of reactions that can be performed on chlorine-terminated polystyrenes, which are generally neglected in comparison with bromine-terminated substrates, by simplifying and adapting synthetic procedures to facilitate their industrial implementation. The functionalized polymers thus obtained may constitute an interesting new class of crosslinking agents, applicable in both conventional and dynamic networks, characterized by tunable properties. In parallel to these experiments, studies are also presented on the kinetics of anomalous crosslinking observed during ARGET ATRP of styrene from bifunctional initiators, the kinetics of ARGET ATRP of sodium styrene sulfonate, the use of different solvent/catalyst pairs as well as the synthesis and use of a new class of bifunctional initiators for ARGET ATRP aimed at obtaining thermostable polystyrenes.File | Dimensione | Formato | |
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