Flax fibres reinforced polylactide modified by ionizing radiation

Polylactide (PLA) composites containing flax fibre strands (20 wt%) and various content of triallyl isocyanurate (TALC) as crosslinking agent were prepared by extrusion and injection moulding processes. The composites were modified by electron beam (EB) irradiation at dose values of 0, 10, 20, 30 and 40 kGy. The effects of EB and TALC on the mechanical and structural properties of the composites were studied using tensile and impact tests, dynamic mechanical analysis (DMA), gel fraction measurement, differential scanning calorimetriy (DSC) and thermogravimetry (TG). However, the main attention was paid to biodegradation effects. Composites were biodegraded by means of enzymatic treatment and industrial composting. The composites were examined using mass loss analysis, DSC and photoelectron spectroscopy (XPS) in order to determine structural changes induced by biodegradation. Application of TALC and EB at dose of 40 kGy led to the increase of tensile strength of about 20%. Besides crosslinking branching of PLA macromolecules was of significant importance. EB irradiation intensified enzymatic and composting degradation, however, when TALC was applied, the composite was much more resistant to these processes.