Valorization of olive husk flour as a filler for biocomposites based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate): Effects of silane treatment

The paper deals with the influence of surface treatment of olive husk flour (OHF) by trimethoxyoctadecylsilane (TMOS) on the morphology and physical properties of bio-composites based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Biocomposites based on PHBV/OHF: 80/20 (w/w) before and after filler treatment were prepared by melt compounding, while the modification of OHF surface by TMOS was performed by thermo-chemical vapor deposition. Scanning electron microscopic observations showed that modification of OHF by TMOS led to homogeneous and finer dispersion of the filler particles in PHBV matrix, indicating improved compatibility between the two components. Further, TGA data revealed an increase in thermal stability of treated PHBV/OHF biocomposites. An increase in the crystalline index determined by DSC was also observed due to the nucleating effect of OHF in the polymer matrix, however more pronounced for the treated biocomposites. The latter exhibited better tensile properties, as confirmed by DMA results, showing higher reinforcing effect of OHF for the treated biocomposites. This study highlighted significant improvements of the properties of PHBV/OHF biocomposites through silane treatment of OHF.