Yaser Hasanzadeh - Takab Co.,R&D dep., Tehran, Iran
Zahed Ahmadi - Color and Polymer Research Center, Amirkabir University of Technology, Tehran, Iran

The reason for choosing polyethylene is its many advantageous properties over metal [1, 2]. Due to requirements of safety and long life the understanding ofwelding of PE pipe-pipe and pipe-fittings has an increased importance [3-6]. Macromolecules mutual diffusion on the weld interface along welding process is essential factor effecton weld consolidation and performance. Tensile behaviour of welded polyethylene was studied by Butler et al. [7, 8].Cavities generation was investigated during the rearrangement of polymer chains and crystalline lamella during tensile test[7, 8]. Attempt has been made by this work to study of PEs welded joint behaviour and properties by investigating of joint performance, physical, mechanical properties and weld interfacial diffusion and separation as a function of macromolecules structure