Nonwovens in space!!!

03 Jul '09

5 min read

Some of the most extreme performance fibres available work very effectively in nonwoven form – including quartz crystal – the world's purest form of silica. Blankets of nonwoven quartz have even been employed as the thermal protection systems of space rocket launchers – thanks to their intrinsic temperature resistance.

They maintain their integrity at temperatures of up to 1,050°C and can be employed for limited periods of exposure at above 1,200°C.

Quartz crystal fibres such as Quartzel, are ground, purified to enhance their chemical purity and fused into silica rods.

These rods are then drawn into fibres and sized for fibre protection and integrity, textile processability and compatibility with resin systems. The fibres can then be turned into both single and plied yarns, rovings, chopped strands, wool or low density felts.

The wool products in coarse form are amorphous, continuous tangled, white and odourless, with no volatile components. They have fibre diameters of between 4 and 9µm. In addition to providing thermal protection for launchers, quartz wool is also employed as ablative material for rocket nozzles and space re-entry vehicles.

Other applications for quartz wool are in the filtration of hot acidic liquids and gases, for furnace closures, as high temperature insulation for the semiconductor industry, and as support in the catalytic converters of heavy duty vehicles.

The wool is impregnated with an organic binder to produce low density nonwoven felts which are employed in aircraft engines, often between two welded foils of refractory alloy. Their superior insulation, performance to weight ratio, resistance to vibrations and high life cycle are appreciated by both civil and military aircraft programmes.

Needle-punched materials made from chopped quartz fibres are also employed in aircraft engine insulation applications, in addition to insulation for industrial ovens and in optical fibre manufacturing.

Nonwovens are also employed as special heat-resistant collars on the Ariane 5 – the European expendable launch system designed to deliver payloads into geostationary transfer orbit or low Earth orbit.

The material in this case is preoxidised carbon, which is needlepunched by French company Duflot Industrie, and has also been adapted to make vandal-resistant material to protect lorries and haulage containers.

Many specialised nonwovens containing such extreme performance fibres will be on display at the next INDEX – the leading show for the nonwovens sector which takes place at Geneva Palexpo from April 12-15 2011.

As was already evident at the last INDEX event in 2008, nanofibres are increasingly being applied to nonwoven filters via electrospinning technology to increase efficiency.

Proposals for the suits of future astronauts have also included such spray-on nanofibre nonwoven webs – if not as first layers, then as additional protective layers.

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