Atomic Force Microscopy, thermal, viscoelastic and mechanical properties of HDPE/CaCO3 nanocomposites

High Density Polyethylene (HDPE) and calcium carbonate (CaCO 3 ) nanocomposites were prepared from masterbatch by melt blending in twin screw extruder (TSE). The physical properties of HDPE/CaCO 3 nanocomposites samples (0, 10 and 20 wt% CaCO 3 masterbatch) were investigated. The morphology, thermal, rheological/viscoelastic and mechanical properties of the nanocomposites were characterized by Atomic Force microscopy (AFM), Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analyzer (DMA) as well as tensile test. The AFM images showed homogeneous dispersion and distribution of nano-CaCO 3 in the HDPE matrix. The DSC analysis showed a decrease in crystallinity of HDPE/CaCO 3 nanocomposites with the increase of CaCO 3 loading. This was due to the presence of nanofiller which could restrict the movement of the polymer chain segments and reduced the free volume/spaces available to be occupied by the macromolecules, thus, hindered the crystal growth. However, there was an increase in crystallization temperature about 1–2 °C with the addition of CaCO 3 . It was suggested that the CaCO 3 nanoparticles acted as nucleating agent. In melt rheology study, the complex viscosities of HDPE/CaCO 3 nanocomposites were higher than the HDPE matrix and increased with the increasing of CaCO 3 masterbatch loading. The DMA results showed that the storage modulus increased with the increasing of nano-CaCO 3 contents. The improvement was more than 40 %, as compared to that of neat HDPE. Additionally, the tensile test results showed that with the addition of CaCO 3 masterbatch, modulus elasticity of nanocomposites sample increased while yield stress decreased.