CONICET | Buscador de Institutos y Recursos Humanos

The sensitivity of Mater bi-Y and sisal fibre composites to long time exposure to different environments: aqueous (biotic) and soil-burial was analyzed. The composite showed lower absorption capacity assigned to strong fibre interactions, due to H-bonds, which produce a physical network preventing the water uptake; in the second zone and after the maximum water uptake was reached, water sorption decreases because of the presence of a competitive event started to take place. After the first 30 days, weight loss occurred. Both materials exhibited the similar degradation patterns. The presence of fibres favours the microfouling which contributes to the leach out low molecular weight compounds. The degradation during indoor burial experiments was also evaluated. Within the first month water sorption was the main event followed by weight loss. Water sorption results demonstrated that composites absorbed less water than the matrix but at higher rate, as it was confirmed by the values of the effective diffusion coefficient. The lower sorption capacity of composites was related to the presence of fibre fibre and fibre-matrix (both of carbohydrate nature) interactions which prevents the water intake and enhances the stability of the material. Within the first 40 days, the water intake promotes the entrance of micro-organisms presents in soil due to the higher water availability within the material, and then biodegradation begins. The result revealed that during the first month, the matrix and composites lost around 7% of their initial mass, due to the leaching of low molecular weight compounds, such as additives. From this point up to the end of the experiment, both materials showed a sustained weight loss. All the materials tested followed the same degradation pattern.

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