Reinforcing Poly(?-caprolactone) with Hollow Glass Microspheres and Hemp Fibers. Morphological, Rheological and Mechanical Properties

In this work composites based on poly(?-caprolactone) (PCL) were prepared and characterized in terms of morphological, rheological and mechanical properties. Two different fillers were used either individually or in combination: hollow glass microspheres (HGM) to obtain lightweight composites and hemp fibers (HF) to increase the mechanical performances of PCL. Moreover, the effect of HF alkaline treatment on the properties of composites was investigated. On the basis of scanning electron microscopy (SEM) inspections, a good dispersion of fillers in the composites was found, and the alkaline treatment of fibers resulted in an improved filler-matrix adhesion. The addition of either HGM or HF has relevant implications on the rheological and mechanical properties enhancing the stiffness of the composites. In particular, the composites reinforced with both HGM and HF exhibit an increase of Young modulus up to 117% and a reduction of theoretical density of about 10% compared to the neat PCL matrix.