Polystyrene/CaCO₃ composites with different CaCO₃ radius and different nano‐CaCO₃ content—structure and properties

Abstract

Abstract The Archimedes' principle and physical theory are attempted to analysis the densification and structure of the polystyrene (PS) composites by melt compounding with CaCO 3 having different particle size. The difference between the measured specific volume (ν) andthe theoretically calculated specific volume (ν mix ), Δν = ν−ν mix , can reflect the densification of the composites. It is clearly demonstrated that the PS composites become more condensed with the reduction of the CaCO 3 particle size. Especially, when the content for nano‐CaCO 3 achieves 2 wt%, the Δν value of the composites reaches the least, which shows the best densification. Meanwhile, the glass transition temperature ( T g ) reaches the maximum value of about 100°C by differential scanning calorimetry (DSC) and thermal mechanical analysis (TMA), which indirectly reveals the composites microstructure more condensed. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveal that 2 wt% nano‐CaCO 3 uniformly disperses in PS composites. The CaCO 3 selected in this experiment has certain toughening effect on PS. The impact and tensile strength increase with addition of nano‐CaCO 3 , but the elongation at break decreases. When nano‐CaCO 3 content achieved 2 wt%, the impact and tensile strength present the maximum value of 1.63 KJ/m 2 and 44.5 MPa, which is higher than the pure PS and the composites filled with the same content of micro‐CaCO 3 . POLYM. COMPOS., 31:1258–1264, 2010. © 2009 Society of Plastics Engineers