Surface properties studies of bivalve shell waste by the IGC technique: Probing its significant potential application in the polymer industry

Bivalve shell waste has the potential to be used as a bio-filler. In this work, the dispersive component (γsd) of surface free energies of the surfaces of clam shell waste (CS) and commercial calcium carbonate (CC) were evaluated using inverse gas chromatography with both the Dorris-Gray method and the Schultz method. Their acid-base character was investigated as well. The mechanical properties of PP composites filled with CS and CC were then studied. The results showed that the γsd calculated with Dorris-Gray method was a bit smaller than that calculated with Schultz method, with a γs,Dorris-Graydγs,Schultzd ratio of 0.98. The surface energy of the CS was significantly heterogeneous and its calculated γsd decreased drastically with increasing surface coverage from 0.5% to 2%, then slightly increased with surface coverage larger than 2%. The Ka/Kb ratio was 7.65 for CS and 1.48 for CC, indicating a more acidic character for the surfaces of CS. The mechanical properties analysis showed that the inclusion of CS powder played mainly a toughening role in the filled PP.