Disentangled State in Polymer Melts; a Route to Ultimate Physical and Mechanical Properties

The role of entanglements in obtaining a homogeneous product of ultra high molecular weight polyethylene (UHMW-PE) has been explored. Studies performed in this report show that a disentangled state before melting is a prerequisite to obtain homogeneous products of an intractable polymer like UHMW-PE. The disentangled state is obtained directly from the reactor by controlling the polymerisation conditions or in the solid state when there is enhanced chain mobility along the c-axis of a unit cell. The disentangled state is maintained in the melt over a period of time. invoking implications in polymer theology. This approach is applicable to polymers in general. The homogeneous fully sintered UHMW-PE, obtained for the first time, shows a considerable decrease in oxygen permeability, and increase in toughness and fatigue resistance. Such homogeneous products of UHMW-PE are of beneficial in highly demanding applications, especially in knee-prosthesis. where the polymer is used as an inlay between the human bone and a metal or ceramic part, which slides against the polyethylene component during normal gait.