The Effects of Coupling Agents on the Mechanical, Rheological and Thermal Properties of Calcium Carbonate-Filled LDPE Compatibilized with Maleic Anhydride-g-LDPE (Part II)

This study deals with the chemical modification of calcium carbonate (CaCO3) by means of coupling agents and its effect on the mechanical, rheological, and thermal properties of the ternary composite of low density polyethylene (LDPE), calcium carbonate (CaCO3), and maleic anhydride-grafted low density polyethylene (MAH-g-LDPE). The variations in the properties were dependent on the treatment method and on the nature and extent of the interactions developed between the filler particles, the matrix and the compatibilizer. The impact resistance results revealed a transition in the behavior of the composite from ductile to brittle. This embrittlement becomes more pronounced as the concentration of CaCO3 and that of the coupling agents are increased. The rheological characterization showed that the interactions developed at the interface greatly affected the flow of the material. The differential scanning calorimetry results showed that even though the fusion temperature and the crystallization temperature were not influenced by the filler or by its treatment, crystallization was altered. Finally, the thermogravimetric analysis showed that the dispersion and the adhesion of the filler with the matrix significantly affect the thermal stability.