Also included in Table 1 is a density packing factor, calculated by dividing the density measured by the maximum density quoted for this material [20], 950 kg/[m.sup.3] except in the case of the compacted only specimen where the density of as-polymerized particles of UHMWPE is used (970 kg/[m.sup.-3]).

These density measurements together with the density packing factors are given in Table 2, showing that for each material the density is greatest at the plunger end and lowest at the die end.

Thus, it would appear that the plunger end was already approaching maximum densification (having a density packing factor of 97%) after the first sintering.

At this stage, the density packing factor of the plunger end material is in the region of 97% and at the midspan it is ~93%.