Title

Chemorheology Investigation of a Glassy Epoxy Thermoset On Tensile Plastic Flow and Fracture Morphology

Document Type

Article

Publication Date

10-1-2015

Department

Polymers and High Performance Materials

Abstract

Reproducible and uncharacteristic tensile stress–strain behavior of cured glassy epoxy-amine networks produces distinctive fracture surfaces. Test specimens exhibiting plastic flow result in mirror-like fracture surfaces, whereas samples that fail during yield or strain softening regions possess nominal mirror-mist-hackle topography. Atomic force microscopy and scanning electron microscopy reveal branched nodule morphologies in the 50-nm size scale that may be responsible for the unusual tensile properties. Current hypothesis is that plastic flow of the glassy thermoset occurs through the existence and deformation of these nodular nanostructures. The thermal cure profile of the epoxy-amine thermoset affects the size and formation of the nodular nanostructure. Eliminating vitrification during thermoset polymerization forms a more continuous phase, reduction in size of the nodules, and eliminates the capacity of the material to yield in plastic flow. This maximizes nanostructure connectivity of the glassy epoxy-amine thermoset and reduces strain to failure significantly. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 1333–1344.

Publication Title

Journal of Polymer Science Part B: Polymer Physics

Volume

53

Issue

19

First Page

1333

Last Page

1344

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