- Syntactic foam
Syntactic foams are
composite materials synthesized by filling a metal, polymeror ceramicmatrix with hollow particles called microballoons. The presence of hollow particles results in lower density, higher strength, a lower thermal expansioncoefficient, and, in some cases, radar or sonar transparency.
Tailorability is one of the biggest advantages of these materials. The matrix material can be selected from almost any metal, polymer or ceramic. A wide variety of microballoons are available, including
cenospheres, glass microspheres, carbon and polymer microballoons. The most widely used and studied foams are glass microballoon- epoxy, glass microballoon— aluminumand cenosphere-aluminum.
compressiveproperties of syntactic foams primarily depend on the properties of microballoons, whereas the tensile properties depend on the matrix material that holds the microballoons togethter. There are two main ways of adjusting the properties of these materials. The first method is to change the volume fraction of microballoonin the syntactic foam structure. The second method is to use microballoons of different wall thickness. In general, the compressive strength of the material is proportional to its density.
These materials were developed in early 1960s as
buoyancyaid materials for marine applications; the other characteristics led these materials to aerospaceand ground transportation vehicle applications. Among the present applications, some of the common examples are buoyancy modules for marine drilling risers, boat hulls, and parts of helicoptersand airplanes. New applications are coming up in sports industry; snow skis and Adidas soccer balls are some of the examples.
Wikimedia Foundation. 2010.