Compatibilization of epoxidized triblock copolymer on the generation of self‐assembled nanostructured epoxies and their surface wettability

Abstract

In this work, we have successfully synthesized epoxidized poly(styrene-blockbutadiene-block-styrene) with the highest epoxidation degree (55 mol%) for the first time by using metachloroperbenzoic acid method. This highly epoxidized styrene-butadiene-styrene (eSBS) block copolymer exhibited good compatibility with the epoxy (diglycidylether of bisphenol-A)/ eSBS block copolymer-4,4 0-diamino diphenyl methane blend. Transmission electron microscope images showed that the eSBS block copolymer formed spherical nanostructure morphology within the blend due to reaction induced phase separation. The addition of eSBS block copolymer in the system significantly improved the wetting parameters such as hydrophilicity, surface free energy, work of adhesion, spreading coefficient and Girifalco-Good's interaction parameter values, which are discussed in detail. The as-prepared selfassembled nanostructured epoxy system will be useful in highly toughened coating applications such as aircraft, automobile, and flooring industries.

Highly Toughened Nanostructured Self-Assembled Epoxy-Based Material—Correlation Study between Nanostructured Morphology and Fracture Toughness—Impact Characteristics

“…The addition of the highest epoxidized SBS (55 mol wt%) that is compatible with epoxy resin leads to viscoelastic phase separation and plasticization effect. The detailed mechanism behind the generation of nanostructured core-shell morphology in epoxy/eSBS55 blend is explained in our previous studies [ 1 , 18 ]. Briefly, when we add 10 phr and 20 phr eSBS55 in epoxy, a homogeneous system appeared initially and later the homogeneity of the system disappeared.…”

“…The epoxidized SBS with a varying epoxidation degree was prepared by using the MCPBA (metachloroperbenzoic acid) method in an inert atmosphere at 0 °C using Hukj as solvent according to our previous report [ 1 , 18 ]. A total of 1 g SBS was dissolved in 70 mL DCM, and stoichiometric amount of MCPBA was added into it.…”

“…The procedure for the preparation for Epoxy/eSBS-0, 5, 10, and 20 phr -DDM blends (phr means parts per hundred) by using the solvent casting method that was described in detail in our previous papers [ 1 , 18 ] In brief, eSBS 55% and epoxy resin were dissolved in THF and heated at 80 °C in an oil bath for the complete removal of the solvent. Stoichiometric amount of DDM hardener was added at 85–90 °C under slow magnetic stirring for 10 min.…”

“…Toughening of epoxy-based thermoset has seen a remarkable surge in research interest during the past several decades [ 1 , 2 ]. The diversity of approaches, and in particular the addition of a second phase such as elastomers, thermoplastics, block copolymers, and nanoparticles, have made remarkable progress in controlling the morphology of epoxy-based multiphase systems in order to produce highly toughened materials [ 3 , 4 , 5 , 6 , 7 , 8 , 9 ].…”

“…In our previous studies, we have demonstrated the synthesis of highly epoxidized SBS (55 mol wt%) triblock copolymer and explained the reaction-induced phase separation, nanostructured morphology, wetting studies, viscoelastic, and thermal studies of blends in detail [ 1 , 18 ]. Highly epoxidized SBS block copolymer can enhance compatibility, and it will be a very good additive for producing nanostructured domains.…”