SIGRATHERM® Graphitized Microballoons

SIGRATHERM<sup>®</sup> Graphitized Microballoons

What are microballoons?

Microballoons are hollow microspheres appearing as a fine powder. In contrast to microcapsules they are not filled with a fluid but with air or an inert gas. Their size can vary considerably depending on their intended use, diameters usually range from 1 - 300 µm. Microballoons are lightweight, chemically stable, have a 1:1 aspect ratio due to their spherical structure and can be made from several materials like glass, ceramics, polymers, metals, carbon and graphite. They function as superior performance fillers and additives in composite materials.

SIGRATHERM graphitized microballoons made by SGL Carbon are unique fillers for various composite materials. They were designed as special functional additives e.g. for polymers to form lightweight, strong and dimensionally stable composites meeting the demands of various applications in the aerospace, navy and high-temperature industries. In addition, SIGRATHERM microballoons can function as non-halogenated flame-resistant and thermal insulation fillers.

Excellent temperature resistance
• in air up to 500 °C (932 °F)
• in inert gas atmosphere and vacuum up to 3000 °C (5432 °F)
Good strength to weight ratio
Chemical inertness
Narrow particle size distribution
Low thermal conductivity
Smooth surface
Excellent compatibility e.g. with various resins

Hollow phenolic resin microspheres are used as raw material to produce SIGRATHERM hollow microspheres. The phenolic beads are first carbonized and afterwards graphitized at 2000 °C (3632 °F) turning into graphitized microballoons with a carbon content of 99.8% and an average particle size of appr. 50 µm.

In contrast to irregularly-shaped fillers, SIGRATHERM graphitized microballoons allow for an optimal packing density due to their spherical structure.

SIGRATHERM microballoons can be used e.g. to produce low-density thermal protection and insulation syntactic foams as well as other high-temperature resistant composite materials. They are suitable to prepare the following composites amongst others:

Epoxy, polyurethane, aminoplast, acrylonitrile-butadiene-styrene, polyester and phenolic resin composite materials
Syntactic polymer foams
Syntactic metal foams

Are you interested in testing SIGRATHERM microballoons for your application? Please contact us.

Read also the article 'Graphitised Microballoons as Functional Additives to Produce Superior Composite Materials' on MatMatch

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Brochures, technical data and information sheets on our products for high-temperature and thermal management applications can be found in our SIGRATHERM Download Center.

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