Reactive Tetrablock Copolymers Containing Glycidyl Methacrylate. Synthesis and Morphology Control in Epoxy−Amine Networks

Abstract

Polystyrene-block-polybutadiene-block-poly(glycidyl methacrylate) (SBG) and polystyreneblock-polybutadiene-block-poly(methyl methacrylate)-block-poly(glycidyl methacrylate) copolymers (SBMG) were synthesized by sequential living anionic polymerization in tetrahydrofuran (THF). SBMG copolymers were used as modifiers for epoxy thermosets based on the diglycidyl ether of bisphenol A (DGEBA). Different techniques including differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and optical cloud point measurements have been used to demonstrate the advantage of having a reactive copolymer to finely tune and control the morphology of nanostructured materials. The FT-IR and DSC studies were used to follow both the kinetics of reaction of the reactive block G with the epoxy-amine system and of cross-linking of the epoxy-amine system. They give an interesting insight into the problem of factors governing the expulsion of the methacrylic block out of the epoxy-amine phase during network formation. Morphological characteristics revealed by TEM appear to be closely related to the optical properties of these composites.

The microstructure and fracture performance of styrene–butadiene–methylmethacrylate block copolymer-modified epoxy polymers

“…In this case, nanostructures are preferred as they would offer the significant toughening from rubber particles without imposing a heavy penalty in processing. Most of the early work on block copolymer modification of epoxy polymers has focused on the morphologies and mechanical properties, with less emphasis on the toughening mechanisms brought about by the respective morphologies [27][28][29][30][31]. The most commonly quoted toughening mechanisms observed were rubbery phase cavitation, debonding, plastic void growth and shear yielding with large damage zones [22,24,25].…”

Characterization of nanostructured epoxy networks modified with isocyanate-terminated liquid polybutadiene

“…This requirement is only achieved by using appropriate hardeners [33,34]. Nevertheless, PS-b-PBD-b-PMMA triblock copolymers containing glycidyl methacrylate [37] or methacrylic acid [38] impart a fine morphology without macrophase separation in the epoxy thermoset blends, because these functional groups react with the reactive groups of the epoxy-hardener system, promoting improved adhesion between blend components. Other reactive block copolymers such as glycidyl methacrylate-based block copolymers [39][40][41][42][43], as well as block copolymers containing oxirane groups along the chain, such as epoxidized polystyrene-b-polybutadiene [44][45][46] also gave rise to nanostrutured materials.…”

Nanostructured Thermosetting Systems from Epoxidized Styrene Butadiene Block Copolymers

“…Several papers have been recently reported well-defined ordered nanostructures in thermosetting epoxy [1][2][3][4][5][6][7][8][9][10] or phenolic resins [11,12] based on the self-assembly capability of block copolymers. In most cases, amphiphilic block copolymers with only one of the blocks miscible with the thermosetting matrix are used as structure-directing agents.…”

“…[1][2][3][4][5] Another feasible pathway for generating selfassembled nanostructures is to use the concept of chemical compatibilization by introducing specific groups in one of the blocks as well as synthesized block copolymers with a reactive block. Indeed, epoxidized polyisoprene-polybutadiene block copolymer [6,7] as well as glycidyl methacrylate [8,9] and methacrylic acid-based copolymers [10] have been synthesized to generate nanostructured thermosetting materials. One potential candidate which fulfils the requirements for using the concept of chemical modification as directing agent for templating of nanostructuration in thermosetting systems is the well known and commercially available polystyrene-block-polybutadiene, PS-b-PB block copolymers.…”