Recycling of natural fibre thermoplastic compounds
Plastics and polymer industry have gained a bad reputation regarding the environmental issues as being responsible of several problems especially climate, energy resources and landfills. That is why focus is switched to natural fibres as an alternative to synthetic fibres. This research studies the influence of recycling on injected moulded thermoplastic natural fibre reinforced parts regarding the thermal, thermo-mechanical behaviour and change in fibre content and shape. Two polypropylene compounds are investigated namely PP – sisal and PP – hemp compounds, where the two polypropylene matrices are modified with MAPP. Processing cycles proved to decrease the fibre content of both compounds where PP-sisal (PP-S) suffers a reduction of fibre content by 26.5% whereas the PP-hemp (PP-H) compound decreased by only 10.2% of the initial value. An increase of 7.2°C and 11.6°C in the Tg (Glass transition temperature) is recorded for the compound PP-S and PP-H respectively. This research has proved the high potential in recycling natural fibres compound since they show improvement in flow and thermal properties after recycling for at least 5 cycles.