Compatibilization improves physico-mechanical properties of biodegradable biobased polymer composites

Biodegradable biobased polymer composites have the advantage of low environmental impact and high sustainability. However, these biocomposites exhibit poor mechanical properties due to poor fiber-matrix bonding. This study evaluated the effect of compatibilization of five biocomposites on their physico-mechanical properties. Composites were prepared with 30 wt% wood fiber and one of the five biodegradable biopolymer: poly(lactic acid) (PLA), polyhydroxybutyrate (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), Bioflex (PLA blend), or Solanyl (starch-based). The composites were compatibilized with 2-3 wt% maleic anhydride, and evaluated for melt flow index, water uptake, hardness, flexural, compressive, impact, and thermal properties. Melt flow index was reduced by 10-16% for compatibilized composites implying the crosslinking of the polymer. Compatibilized composites of PLA, Bioflex, and PHBV exhibited improved thermal and strength properties, and reduced water absorption. These improvements were attributed to the enhanced fiber-matrix interfacial interaction caused by the compatibilizer. However, compatibilization did not work in PHB and Solanyl.