Ramin Hossein Nezhad - Institute of Polymeric Materials, Sahand University of Technology, Tabriz, Iran. Department of Polymer Engineering, Sahand University of Technology, Tabriz, Iran.
Mostafa Rezaei - Polymer Engineering Department, Sahand University of Technology, Tabriz, Iran. Institute of Polymeric Materials, Sahand University of Technology, Tabriz, Iran
Saeid Talebi - Institute of Polymeric Materials, Sahand University of Technology, Tabriz, Iran. Department of Polymer Engineering, Sahand University of Technology, Tabriz, Iran.

Ultra high molecular weight polyethylene (UHMWPE) is a high performance polymer with excellent properties, such as high abrasion resistance, low coefficient of friction, selflubrication etc. Because of its high molar mass, conventional processing methods cannot be used, and so it is commonlysintered. Sintering is a term usually used to describe the formation of a homogeneous melt from the coalescence of solid particles under the action of surface tension. Duringsintering, there is a thermodynamic driving force for particles to lower their surface energy by reducing their surface area [1- 4].