Biocomposites based on poly(hydroxybutyrate) and the mesocarp of babassu coconut (Orbignya phalerata Mart.): effect of wax removal and maleic anhydride-modified polyethylene addition

Abstract

Aiming to adds value to agricultural products and develop environmental-friendly and cost-effective materials, the present work investigates the influence of babassu mesocarp (BM) flour extractives and the addition of maleic anhydride-modified polyethylene (MAPE), as a coupling agent, on the properties of additivated polyhydroxybutyrate (PHBad)/BM biocomposites. The extractives were partially and completely removed from BM flour by detergent and soxhlet extraction, respectively, before biocomposites melt processing. The thermal, mechanical, structural, morphological, and flow properties of biocomposites with extracted BM flours were determined and compared to the properties of biocomposite with BM flour in natura. In addition, the influences of MAPE incorporation in the properties of each biocomposite were also studied, in order to understand their role in biocomposite compatibilization. The particle treatments resulted in biocomposites with lower tensile strength than biocomposites with BM in natura. Despite the low compatibility of MAPE with PHB, the addition of MAPE increased the tensile strength of the respective PHB biocomposite, reaching values of tensile strength similar or slightly higher than the PHBad-MAPE matrix. Therefore, MAPE acted as an effective additive for BM flour, probably, due to reactive processing with the starch polar surface groups. Since BM was abundantly and cheaply available, its use with PHB and MAPE resulted in biodegradable material with similar mechanical properties of neat PHB and concomitant reduction in cost.

Keywords

• Biocomposite
• Babassu coconut
• Mesocarp
• Particle-reinforcement
• Surface treatment