Poly(lactic acid)-hemp-nanosilica hybrid composites: Thermomechanical, thermal behavior and morphological properties

PLA-hemp-nanosilica composites were prepared by a film stacking method, using hot compaction in a heated press with interspersed layers of hemp fibre. Dynamic mechanical properties measured with modulated force thermomechanometry (mf-TM) showed that the storage modulus increased with increase in filler loading due to increasing restriction to mobility of polymer molecule. The loss modulus and tan(?) in contrast showed an opposite trend. Thermal property of the composites was assessed using differential scanning calorimetry (DSC). DSC results were determined with increasing scanning rate, the temperature of a low melting peak increased. Double melting behaviour appeared in the heating curve when using a slower scanning rate. Nano-silica promoted small and imperfect crystals that changed successively into more stable crystals through a melt-recrystallization process.