Biodegradation of sheep wool geotextiles

• The progress of biodegradation of woollen geotextiles designed for erosion control during one year was analysed.
• The progressive degradation of fibres from the cuticle to the cortex was revealed.
• The potential of woollen geotextiles to maintain their protective potential for one vegetation session was proved.

Innovative geotextiles designed for erosion control and made from meandrically arranged coarse ropes were produced. The ropes filled with sheep wool and wrapped with woollen nonwoven were buried in the local ground. During one year of soil exposure the progress of wool biodegradation was observed. During investigations the morphology and chemical composition of wool and change of basic mechanical parameters of single fibres and woollen nonwoven were analysed. In the first months of the burial the deterioration of mechanical parameters, destruction of scales on the fibres surface and cleavage of disulphide bonds of keratin was observed. In the following months, further reduction of mechanical parameters, successive destruction of cuticle and deeper layers of the fibres followed by fibres defibrillation and the disruption of peptide bonds occurred. Rapid biodegradation leading to defibrillation occurred in the mechanically damaged fibres. It was concluded that, thanks to slow biodegradation, the ropes maintain their protective potential for one vegetation session, what is sufficient for the development of the protective vegetation on the slope.