Controlled epoxidation of poly(styrene-b-isoprene-b-styrene) block copolymer for the development of nanostructured epoxy thermosets

To be used as templates for nanostructured thermosets, a commercial poly(styrene-b-isoprene-b-styrene) (SIS) block copolymer (BCP) was epoxidized by three different epoxidation procedures. An exhaustive analysis of methodologies using metal catalyzed/hydrogen peroxide, dimethyldioxirane (DMDO), and...

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Detalles Bibliográficos
Autores principales: Goyanes, Silvia Nair, D'Accorso, Norma Beatriz
Publicado: 2011
Materias:
block copolymers
dimethyldioxirane
epoxidation
nanocomposites
phase separation
thermosets
Atomic force microscopy
Catalysis
Crosslinking
Epoxidation
Isoprene
Nanocomposites
Oxidation
Peroxides
Phase separation
Styrene
Thermosets
Chromatographic techniques
Diglycidyl ether of bisphenol-A
Dimethyldioxirane
Epoxy thermosets
Macro phase separation
Metal-catalyzed
Nano-structured
Nanostructured thermosets
Block copolymers
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0887624X_v49_n20_p4505_Garate
http://hdl.handle.net/20.500.12110/paper_0887624X_v49_n20_p4505_Garate
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
Descripción
Sumario:To be used as templates for nanostructured thermosets, a commercial poly(styrene-b-isoprene-b-styrene) (SIS) block copolymer (BCP) was epoxidized by three different epoxidation procedures. An exhaustive analysis of methodologies using metal catalyzed/hydrogen peroxide, dimethyldioxirane (DMDO), and meta-chloroperbenzoic acid (m-CPBA) was performed to obtain reactive BCPs. The DMDO approach was the best strategy to obtain highly epoxidized SIS BCP (85 mol %) without formation of side products. Careful control in BCP epoxidation by metal catalyzed/hydrogen peroxide and m-CPBA approaches led to a maximum epoxidation degree (ED) of approximately 60 mol % without the formation of side products. The ED by metal catalyzed/hydrogen peroxide strategy could be further increased to 69 mol %, but a significant amount of crosslinking, ring opening, and polymer chain scission reactions were detected by spectroscopic and chromatographic techniques. The miscibility of epoxidized BCPs with diglycidyl ether of bisphenol-A epoxy system before and after curing was analyzed to develop nanostructured epoxy thermosets. For ED higher than 69 mol %, BCPs were miscible, while those with lower ED presented macrophase separation. Highly epoxidized BCPs obtained by the DMDO methodology were successfully used to obtain ordered nanodomains inside the epoxy matrix, as determined by atomic force microscopy. © 2011 Wiley Periodicals, Inc.

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