15 Oktober 2008

Gummi mit Selbstheilungsfähigkeit

Ein Elastomer aus Pflanzenöl und Harnstoff repariert sich selbstständig

Die Arbeitsgruppe um Philippe Cordier an der Ecole Supérieure de Physique et de Chimie Industrielles haben ein neues Elastomer entwickelt, das sich bei einem Riss selbst wieder reparieren kann. Das Material besteht aus Pflanzenölen und einer Harnstoffverbindung und ist damit vollständig biologisch abbaubar. Cordier et al. veröffentlichten ihre Ergebnisse in der Zeitschrift Nature im Februar 2008.

Englischer Abstract:
Rubbers exhibit enormous extensibility up to several hundred per cent, compared with a few per cent for ordinary solids, and have the ability to recover their original shape and dimensions on release of stress. Rubber elasticity is a property of macromolecules that are either covalently cross-linked or connected in a network by physical associations such as small glassy or crystalline domains ionic aggregates or multiple hydrogen bonds. Covalent cross-links or strong physical associations prevent flow and creep. Here we design and synthesize molecules that associate together to form both chains and cross-links via hydrogen bonds.

The system shows recoverable extensibility up to several hundred per cent and little creep under load. In striking contrast to conventional cross-linked or thermoreversible rubbers made of macromolecules, these systems, when broken or cut, can be simply repaired by bringing together fractured surfaces to self-heal at room temperature. Repaired samples recuperate their enormous extensibility. The process of breaking and healing can be repeated many times. These materials can be easily processed, re-used and recycled. Their unique self-repairing properties, the simplicity of their synthesis, their availability from renewable resources and the low cost of raw ingredients (fatty acids and urea) bode well for future applications.

Weitere Informationen:

Source: research*eu, 2008-06, und Nature, 2008-02.

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