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Doctoral Thesis
DOI
https://doi.org/10.11606/T.75.2021.tde-18082022-083135
Document
Author
Full name
Patricia Borim
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2021
Supervisor
Committee
Cavalheiro, Carla Cristina Schmitt (President)
Silva Filho, Luiz Carlos da
Albas, Agda Eunice de Souza
Roveda Junior, Antonio Carlos
Santos, Willy Glen
Title in Portuguese
Exploring methods to synthesize polymers with complex architecture by radical polymerization via a combination of  "catalyst free" RAFT and ATRP
Keywords in Portuguese
ATRP
Networks
RAFT
RDRP
STEM gels
Abstract in Portuguese
Inicialmente, seis diferentes monômeros foram estudados para Polimerização Radicalar via Adição Fragmentação Reversível (RAFT) fotoinduzida sob luz verde. Os monômeros utiliados foram: poli(etileno glicol) metacrilato de metil éter (PEG300MA and PEG550MA), metacrilato de butila (BMA), metacrilato de polidimetilsiloxano (PDMSMA), lauril metacrilato (LMA) e metacrilato de 2-(dimetilamino)etil (DMAEMA). A fotopolimerização de todos os monômeros, exceto para BMA e LMA, por RAFT sem catalisador sob luz verde mostrou-se descontrolada, enquanto BMA e LMA forneceram alta conversão e baixa polidispersividade: de 95%; 1,31 e 80%; 1,35, respectivamente. Em um segundo aspecto a tese investigou alguns agentes de transferência que foram adicionados à Polimerização por Radicais Livres (FRP) para permitir o cálculo do coeficiente de transferência do halogênio para a cadeia de propagação, a fim de determinar a rapidez com que ocorre e também para encontrar uma molécula ideal para fazer estruturas do tipo "bottlebrush". Os melhores resultados foram obtidos com etilbromo-α-isobutirato (EBiB) onde foi determinado um coeficiente de transferência (Cs) igual a 0,0162. Além disso, estruturas de polímeros em rede foram sintetizadas por FRP e estruturas funcionalizadas foram preparadas usando RAFT e Polimerização Radicalar por Transferência de Átomo (ATRP). Observou-se que redes altamente reticuladas podem ser frágeis, mas a preparação de géis com estruturas macromoleculares projetados e estruturados (STEM) altamente sintonizáveis podem ser preparados por procedimentos de polimerização radicalar de desativação reversível (RDRP). Esses polímeros de rede foram caracterizados por testes de inchamento. Em um último momento da pesquisa, novas redes poliméricas com diferentes funcionalidades foram sintetizadas por FRP, onde a cadeia principal é composta por metacrilato de metila (MMA) e, PEG550DMA foi utilizado como agente de reticulação (crosslinking), enquanto LMA, 1-pirenometil metacrilato e 2- cloridrato de metacrilato de aminoetila foram utilizados para funcionalizar esses polímeros. Eles foram caracterizados por reologia, análise termogravimétrica (TG/DTA), UV-vis e Fluorescência.
Title in English
Exploring methods to synthesize polymers with complex architecture by radical polymerization via a combination of  "catalyst free" RAFT and ATRP
Keywords in English
ATRP
networks
RAFT
RDRP
STEM gels
Abstract in English
Initially, six different monomers were examined for Reversable Addition Fragmentation chainTransfer Polymerization (RAFT) photoinduced polymerization under green light. The monomers used were: poly(ethylene glycol) methyl ether methacrylate (PEG300MA and PEG500MA), butyl methacrylate (BMA), poly(dimethylsiloxane) methacrylate (PDMSMA), lauryl methacrylate (LMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA). Photo polymerization of all monomers, except for BMA and LMA, by catalyst free RAFT under green light appeared to be very uncontrolled while BMA and LMA provided high conversion and low dispersity of 95%; 1.31 and 80 %; 1.35, respectively. In a second aspect of the research program, some transfer agents were added to Free Radical Polymerizations (FRP) in order to allow calculatation of the transfer coefficient from the halogen to propagating chain in order to determine how fast it occurs and also to find a good molecule to make bottlebrushes structures. The best results were obtained with ethylbromo-α-isobutyrate (EBiB) where we determined a transfer coefficient (Cs) equal 0.0162. Also, network polymers structures were synthetized by FRP and functionalized structures were prepared by using RAFT and Atom Transfer Radical Polymerization (ATRP). It was observed that highly crosslinked networks can be brittle but the preparation of highly tunable Structurally Tailored and Engineered Macromolecular (STEM) gels could be prepared by Reversible Deactivation Radical Polymerization (RDRP) procedures. These network polymers were characterized by swelling tests. In the last aspect of the research, novel polymer networks with different functionalities were synthetized by FRP, where the main chain is composed of methyl methacrylate (MMA), and PEG550DMA was used as crosslink agent, while LMA, 1-pyrenemethyl methacrylate and 2- aminoethyl methacrylate hydrochloride were used to functionalize these polymers. They were characterized by rheology, thermogravimetric analysis (TG/DTA), Differential Scanning Calorimetry (DSC), UV-vis and Fluorescence.
 
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Publishing Date
2022-08-19
 
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