An approach

mild mixing

has been demonstrated for the preparation of polymer/CaCO3 nanoparticle composite in twin-screw extruder.In this method

the pre-dispersed nanoparticle suspensions were blended with melting polymers

PP

PE

PC and PBT

in a weak shearing field using an extruder

followed by removing the water from vent.The four typical polymeric nanocomposites were prepared by mild mixing.The dispersion quality of nano-CaCO3 in the matrix of polymer was characterized by scanning electron microscopy (SEM)

and the nano-CaCO3 was found to be dispersed in polymer matrix at the nanoscale.The molecular weights of PC and its nanocmposite showed that degradation did not occurr in the process.The mechanical properties of composites had increased slightly with the content of 1.5 wt％ nano-CaCO3. It proved that the approach was suitable for the preparation with polar and non- polar polymers.