Biodegradation in simulated soil of HDPE/pro-oxidant/rice husk composites: application in agricultural tubes

Resumo

The use of agricultural waste, such as rice husk (RH), for the production of cheap and eco-friendly polymer
composites has emerged as a promising field of interest. The aim of this work was the preparation of highdensity
polyethylene (HDPE)-based composites reinforced with rice husk and an organic pro-oxidant (EG15)
for the production of seedlings tubes. Photodegradation and degradation tests in simulated soil were performed
for 90 and 180 days in order to study the decomposition of these composites. The SEM and OM images
suggest that degradation of the composites samples was more extensive than the pure HDPE samples,
probably because the composites present intense light absorption in the UV range, facilitating the degradation
process even before biodegradation begins. In addition, after introducing RH particles in the polymeric matrix,
the mechanical tensile and flexural properties, experienced significant changes, suggesting that the RH
particles were homogeneously dispersed throughout the polymer matrix. Finally, the results have demonstrated
that HDPE, RH, and EG15 are attractive materials for the design of polymeric composites for the production
of seedlings tubes with excellent mechanical properties, being also easily decomposed in the environment
once discarded.
Keywords: Polymer composites, High-density polyethylene, Rice husk, Biodegradation, Mechanical properties.