Mechanical behavior of alumina/polymethylmethacrylate nanocomposites.

Journal Article · Mon Sep 01 04:00:00 EDT 2003 · Proposed for publication in Macromolecules.

OSTI ID:1005439

Schadler, Linda S ^[1]; Siegel, Richard W ^[1]; Ash, Benjamin Jesse

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1. Rensselaer Polytechnic Institute, Troy, NY

Alumina/poly(methyl methacrylate) (PMMA) nanocomposites were synthesized using 38 and 17 nm alumina nanoparticles. At an optimum weight fraction, the resulting nanocomposites display a room-temperature brittle-to-ductile transition in uniaxial tension with an increase in the strain-to-failure that averages 40% strain and the appearance of a well-defined yield point in uniaxial tension. Concurrently, the glass transition temperature (T{sub g}) of the nanocomposites drops by more than 20 C. The brittle-to-ductile transition is found to depend on poor interfacial adhesion between polymer and nanoparticle. This allows the nucleation of voids, typically by larger particles ({approx}100 nm), which subsequently expand during loading. This void formation suppresses craze formation and promotes delocalized shear yielding. In addition, the reduction in T{sub g} shrinks the shear yield envelope, further promoting this type of yield behavior. The brittle-to-ductile phenomenon is found to require both larger particles for void growth and smaller particles that induce the lowering of yield stress.

• Research Organization: Sandia National Laboratories
• Sponsoring Organization: USDOE
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 1005439
• Report Number(s): SAND2003-3570J
• Journal Information: Proposed for publication in Macromolecules., Journal Name: Proposed for publication in Macromolecules. Journal Issue: 4 Vol. 37
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ADHESION
GLASS
NUCLEATION
POLYMERS
SHEAR
STRAINS
TRANSITION TEMPERATURE