Mechanical properties and interfacial interaction of CaCO 3 filled HDPE compatibilized with HDPE functionalized by ultraviolet irradiation

The mechanical properties of CaCO 3 filled high density polyethylene (HDPE) compatibilized with ultraviolet (UV) irradiated HDPE (uHDPE) were studied and the interfacial interactions between CaCO 3 and the polymers were evaluated by SEM, the Molau test, and ESCA. UV irradiation in air introduces the following functional groups on HDPE: >COOH, >CO, OOH and OH. The concentration of these groups increases with irradiation time. The addition of a small amount (<10% by wt) of uHDPE to the HDPE/CaCO 3 improves the tensile and impact strength. For example, the addition of 3% HDPE irradiated for 500 hours (u500HDPE) increases the tensile and impact strength of HDPE/CaCO 3 from 16.7 MPa and 210 J/m to 25.2 MPa and 430 J/m, respectively. Chemical reactions between uHDPE and CaCO 3 promote interactions between HDPE and CaCO 3 . The morphology of the compatibilized compound is nearly homogenous, and no CaCO 3 sediment was observed in a hot xylene solution of HDPE/u500HDPE/CaCO 3 when the content of u500HDPE exceeded 30% (wt).