Study of structural characteristics of HDPE/CaCO3 nanocomposites by positrons

The positron lifetime spectra were measured as a function of weight fraction Phi(w) of CaCO3 nanoparticles in the high-density polyethylene/CaCO3 (HDPE/CaCO3) (Polymer) nanocomposites. it is observed that, first, positronium (Ps) is formed and annihilates in the free-volume hole of HDPE and the free-volume concentration decreases with increasing fraction of the CaCO3 nanoparticles in the HDPE/CaCO3; second, the positron lifetime tau(2) and its intensity I-2 are strongly affected by the structure of the interface layer between CaCO3 nanoparticles and HDPE matrix. (C) 2003 Elsevier Science Ltd. All rights reserved.