Toughening Interphases for Composites

In composites reinforced with brittle materials, control of the matrix-filler interphase provides an opportunity for enhancing composite toughness.  Our laboratory has been involved in examining the toughening potential of rubbery or high-ductility additives that are located at the interphase.  Most recently, in a collaboration with Scott Sieburth we have sought to recreate the energy-absorbing strategies of nacre proteins in synthetic β-lactams in order to develop novel composites for biomaterial applications.

CURRENT PROJECTS

Bones, teeth, spider silk and nacre are just a few of the well-known biomaterials that display exceptionally high tensile strengths, hardness, or toughness. Our approach to composite design is inspired by the adhesive proteins of nacre (mother of pearl) that bind the inorganic component and give it great toughness. These elastic biopolymers serve as relatively flexible, crack-deflecting interphase between the mineral particles; its strength and strong bond to aragonite provides the finished material (nacre) with impressive toughness.

To generate alternative synthetic analogs of the organic protein glue, we are using b-peptides. Unlike a-amino acid proteins, β-peptides are significantly resistant to enzymatic degradation. The ring-opening of β-lactams has been the only method shown to yield high-molecular weight polymers.

Our research has focused on the following areas:

Synthesis

A diversity of organic compounds including monomers, co-initiators, and linkers were synthesized.