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Authors
Advisor(s)
Abstract(s)
This work was devoted to the synthesis, characterization, and kinetic modeling of polyacrylonitrile (PAN) products formation. Different reaction mechanisms were considered in the framework of acrylonitrile polymerization, namely Free Radical Polymerization (FRP) and two Reversible-Deactivation Radical Polymerization (RDRP) techniques: Reversible Addition-Fragmentation Chain Transfer (RAFT) and Atom Transfer Radical Polymerization (ATRP). Furthermore, diverse polymerization conditions were also considered, namely bulk polymerization, reaction in dimethylformamide solution and precipitation in ethanol/water mixtures. The goal of these studies was the assessment of the synthesis conditions on the PAN molecular architecture, namely the polymer molecular weight distribution (MWD) and correspondent averages. Within this purpose, products were characterized using Size Exclusion Chromatography (SEC) with Refractive Index (RI) and Light Scattering (LS) detection. For comparative purposes samples of PAN produced at industrial scale were also included in these characterization studies.
The experimental work was complemented with kinetic modeling studies for PAN production in different reaction conditions. These models include some complex issues associated to acrylonitrile polymerization, namely heterogeneous phase systems, non-isothermal runs, inhibition, besides the possibility to describe ATRP and RAFT polymerization. Simulations obtained help to understand some peculiar results observed for PAN formation.
Experimental and theoretical results obtained in this work show that the synthesis conditions have a huge impact in PAN molecular architecture, namely the MWD and averages. Therefore, the design of the synthesis process can be considered to obtain tailored materials based in PAN. Especially important in this context is the possibility to design advanced PAN functional materials for technical applications with the use of ATRP and RAFT polymerization.
This work contains confidential information in the framework of the collaboration with the company SGL Carbon.
Description
Mestrado de dupla diplomaĆ§Ć£o com a UNIFACS - Universidade Salvador
Keywords
Polyacrylonitrile Free radical polymerization RAFT polymerization ATRP Light scattering