BioMatNet Item: FAIR-CT97-3784 - Optimisation of the production chain for high performance "light natural sandwich materials" (LNS) as a basis for scaling-up

FAIR-CT97-3784
Optimisation of the production chain for high performance "light natural sandwich materials" (LNS) as a basis for scaling-up

Contacts
Further Information

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Biocomposites/Boards : FAIR Area 1.2 - Green Chemicals and Polymers Chain : Fibre

	Type of Project	Shared Cost
	Contract No	FAIR-CT97-3784
	Total Cost
	EC Contribution
	Start Date	01/07/1998
	Duration	36 Months

Optimisation of the production chain for high performance "light natural sandwich materials" (LNS) as a basis for scaling-up

Objectives

The Wilhelm-Klauditz-lnstitut at Braunschweig in cooperation with Tubus Bauer Company at Bad Sackingen are currently developing a light natural sandwich material (LNS) with wood based top layers and a core of evenly orientated hollow plant stalks embedded in a matrix of natural foam. These natural sandwich materials are very light and extremely rigid. The production of LNS comprises an environmentally friendly primary production, manufacture, processing and disposal. LNS can be used for a broad range of applications. In this proposal it is aimed to substitute sandwich materials made from plastics or light metals regarded as 'high tech - products' and used in vehicle construction and transport systems. Many companies have already expressed their interest in using LNS.

Technical Approach

The overall objective is to provide the basis for scaling up the production of high performance LNS by further development of the whole chain from the primary production of the stem raw material to the technical processing of LNS. This will be done by:

use of pure plant-based core foam matrix and bonding adhesives in top layers
a comparison of system quality characteristics for suitability of LNS using different crops: Arundo donax, bamboo, Miscanthus, annual and perennial rye, triticale, hemp and nettles
improvement of the stalk raw material by developing an optimised cultivation method with emphasis on Miscanthus
production and testing of pilot products in cooperation with commercial partner

State of the art

The manufacture of light sandwich materials is mainly based on PVC, polyurethane or aluminium. The use of synthetic materials is critical with respect to production and disposal, and the production of aluminium based sandwich materials needs a very high energy input.

A number of test products of natural sandwich materials have already been produced but the production of LNS is only on a laboratory scale. Upscaling to commercial applications is hampered by specific technical problems: wide variation in stem quality, embedding of stems in an appropriate foam matrix, substitution of phenolic based synthetic adhesives in top layers with natural components.

Depending on the application of the sandwich, the core material can be made from stems from a number of different plant species with differences in stem characteristics markedly influencing the stability flexibility and the weight of the final product. Miscanthus has given so far the best results but uneven and crooked plant stems (as for other crops) often cause problems. However, the material from some Miscanthus fields has been found to be almost optimal - the cause therefore has still not been investigated.

In economic terms, the introduction of LNS to the market stands a good chance. The production costs of LNS in a technical scale are estimated to be 175 - 350 ECU/m³, far below those for plywood (500 - 850 ECU/m³) or sandwich materials based on plastics (beginning at l500 ECU/m³).

Results to Date

Expected results for the first year are:

Primary production

Establishment of field trials concerning different varieties of wheat, rye and Triticale
Method studies on analysing plant stem morphological and anatomical traits with emphasis on Miscanthus
Development and field testing of a "top-cutter" and a harvester for Miscanthus whole stems

Manufacture of LNS

Harvesting of wheat straw for LNS specimen production.
Development and testing of natural foams and blends as foam matrix.

Product presentation

Co-operation with the eco-village "Hjorsthoj" on the demonstration of LNS as a building material.

Harvesting and bailing

Miscanthus

Light natural sandwich materials

Contacts

Coordinator

Danish Institute of Agricultural Sciences Dept of Crop Physiology & Soil Science / DENMARK

EC Scientific Officer

Ciarán MANGAN / European Commission - DG Research Quality of Life Programme - Unit B1.2 / BELGIUM

Participant