Ageing, optical and life-cycle analysis of clay-reinforced cassava starch biocomposites

Abstract

Bioplastics’ life cycle assessment (LCA) is a vital tool for evaluating their environmental impact. It makes it possible to measure the consequences throughout the life cycle, from creation to the end of life. New composites are increasingly tending to be part of a circular economy. It is therefore essential to know how they behave (production, processing, uses, ageing, composting, etc.) throughout the recovery cycle. Additives make it simple to plastify starch, a naturally occurring polymer. However, the primary characteristics of thermoplastic starch-based polymers are their high-water sensitivity and malleable mechanical qualities. For packing purposes, they are either heat-treated or not, and strengthened with kaolin and metakaolin. The objective of this work is to evaluate the life cycle and aging of clay-reinforced cassava starch-based biocomposites. To do this, a clay denoted KB from Bonoua composed mainly of quartz (14 %) and clay minerals kaolinite (75 %) and illite (11 %) and cassava starch (powder) with a median diameter of 19 μm were used. The biocomposites developed by the evaporative casting method were reinforced with kaolin (noted BPKB) and metakaolin (heat-treated kaolin at 700 °C/1h) (noted BPMKB). Based on investigations into thermal, optical, and biodegradation processes, it seems that in the UV-B, UV-A, and visible spectrums, biocomposites become most opaque at wavelengths of 300 nm, 350 nm, and 750 nm. Kaolin and metakaolin reinforced biocomposites (BPKB and BPMKB) are resistant up to 150 °C. Biocomposites placed in the soil or on the surface degrade up to 98 % (m/m). Degraded biocomposites can be used as compost and fertilizer for cassava crops.