Alternative insulation made from modified lignocellulosic fibers

Status

finished

Summary

Natural building-materials will be important for sustainability in the future, and extensive insulation is an important measure which we have to consider today as a way of protecting our environment.

In Austria at present, insulators are mainly made from mineral fibres (relatively high primary energy requirement) or synthetic material foams (using mineral oil as the raw material). Several products made from plant or animal materials are also available, but the market share of this alternative insulation is less than 10 %. Current disadvantages of these insulators made from biogenic materials are handling problems, flammability and their lack of availability in large quantities for industry.

The aim of this project, therefore, is to develop alternative insulation made from lignocellulosic fibres. This would have the following advantages:

• The raw material, wood, is available in sufficient quantity in Austria (only two thirds of the wood re-growth is used)
• Pulp is produced in closed process cycles and production can be extended easily
  

Within this project a new approach is planned to meet the flammability demands of the Austrian Institute of Civil Engineering. This shall be accomplished by modifying the hydroxyl-groups of lignocellulosic fibres. The principal benefit of this reactive approach is the non-migratory nature of this "active agent" due to its good binding to cellulosic fibre. Up until now, borates, aluminium sulfate and ammonium phosphate have been used as additives to the insulation material. Consequently, these insulators are only conditionally dumpable as the impregnating substances get washed out and might exceed maximum limits in the leachate from landfills. Modifying functional groups of cellulose will be accompanied by research into environmentally safe alternatives to the ecologically harmful additives mentioned above. Besides this, fibre modification may also positively influence moisture absorption by the insulation.

Insulation material has to be protected against micro-organisms and insects etc. Usually this is done through the addition of insecticides, which have possible side effects. Within this project, biocides will be applied which are based on new active mechanisms which interfere with the development cycle of pests.

At present, cellulose insulation is either in the format pressed boards or flocks, which means expensive installation work. The aim of this project is to develop an insulation in the form of fleece or matting which grants easy and flexible installation. After this research work has been completed in laboratory, pilot plant studies on industrial production of the insulation material are planned, in co-operation with mechanical engineers.

In conclusion, it can be said that the importance of the project is based on the development of an innovative, environmentally safe insulation material made from lignocellulosic fibres, which will also give the Austrian construction industry a competitive advantage.

Contact

Dr. Show-Ling Lee-Müller
Holzforschung Austria
Franz-Grill-Straße 7
A 1031 Wien
Tel.: +43 1 798 26 23 - 51
Fax: +43 1 798 26 23 - 50
E-mail: S.Lee-Mueller@holzforschung.at