Control of the block copolymer morphology in templated epoxy thermosets

Abstract

It has been found that by the addition of low concentrations of an amphiphilic block copolymer to an epoxy resin, novel disordered morphologies can be formed and preserved through curing. This article will focus on characterizing the influence of the block copolymer and casting solvent on the templated morphology achieved in the thermoset sample. The ultimate goal of this work is to determine the parameters that would control the microphase morphology produced. Epoxy resins blended with a series of amphiphilic block copolymers based on hydrogenated polyisoprene (polyethylene-alt-propylene or PEP) and polyethylene oxide (PEO), specifically, were investigated. In this article, the cure-induced order-order phase transition from the spherical to wormlike micelle morphology will also be discussed. It is proposed that the formation of the wormlike micelle structure from the spherical micelle structure is similar to the phase transition behavior that occurs in dilute block copolymer solutions as a function of the influence of the solvent on micelle morphology.

Innovative materials of this era for toughening the epoxy matrix: A review

“…In water solutions, the evolution from spherical micelles-wormlike micellesoctopi-jellyfish-vesicles was experienced with the increase in the hydrophobic block of the BCP with respect to the hydrophilic one. Wormlike micelles constitute the appropriate morphology for the toughening purpose [154,155,[170][171][172][173][174][175]. An elaborate study by Davidock et al [173] illustrates the intricacy in forecasting the conditions needed to generate wormlike micelles.…”

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

“…In other systems, the epoxy prepolymer and the block copolymer can provide a homogeneous solution before curing, but during the curing process the nanostructure can form through a mechanism called reaction-induced microphase separation [9]. Some examples of the copolymers that give rise to nanoscopic structures include diblocks and/or triblocks of poly(ethylene oxide) with polycaprolactone (PEO-b-PCL) [9], poly(propylene oxide) (PEO-b-PPO) [10][11][12][13][14][15], poly(hexylene oxide) (PEO-b-PHO) [16], poly(n-butylene oxide) (PBO-b-PEO) [17], poly(ethyl ethylene) (PEO-b-PEE) [7,8], poly(ethylene-alt-propylene) (PEO-b-PEP) [7,8,[18][19][20][21], low molar mass polyethylene (PEO-b-PE) [22], polystyrene (PEO-b-PS) [23], and polydimethylsiloxane (PEO-b-PDMS) [24]; block copolymers of polycaprolactone with polydimethyl-siloxane (PCL-b-PDMS-b-PCL) [25,26], poly(n-butyl acrylate) (PCL-b-PBA) [27], polybutadiene(PCLb-PBD-b-PCL) [28], polystyrene (PCL-b-PS) [29], or poly(butadiene-co-acrylonitrile) (PCL-b-PBN-b-PCL) [30]; block copolymers of poly(methyl methacrylate) with polystyrene (PMMA-b-PS) [31,32], and ABC-type triblock copolymer composed of polystyrene-b-polybutadiene-b-poly(methyl methacrylate) (PS-b-PBD-b-PMMA) [33,34], and polydimethyl-siloxane-b-polycaprolactone-b-polystyrene (PDMS-b-PCL-b-PS) [35]. The formation of ordered nanostructures in these epoxy networks occurs because the PCL, PEO or PMMA block segments in these corresponding copolymers remain miscible with the epoxy matrix after curing, whereas the other immiscible block components separate out.…”

Studies on mechanical, thermal and dynamic mechanical properties of functionalized nanoalumina reinforced sulphone ether linked tetraglycidyl epoxy nanocomposites

“…Hence, structural modication of epoxy resins along with suitable nanoreinforcements to achieve enhanced thermal and thermo mechanical properties is required for high performance industrial applications. [14][15][16][17] Introduction of sulphur group in to epoxy resins offers excellent thermal stability, high moisture resistance, low ionic contaminant concentration, and good dielectric properties. The addition of inorganic nanoparticles, carbon nanotubes and carbon akes are the widely used as nanometric reinforcements for epoxy matrices to enhance their mechanical behavior.…”