B) Effect of Differential Thermal Expansion
Thermal expansion of XLPE is a strong function of temperature,
as seen in Figure 10. In addition, the yield stress drops
precipitously as the material expands between about 90 and 110º
C
(Figure 10). For mechanical purposes, XLPE is a “filled” material,
and the reinforcing filler is the crystalline XLPE. As thmelts, the yield stress drops from the range of 60 MPa to well
below 1 MPa. This reduction in yield stress is a major complicating
factor for the design of accessories, as on the one hand,
substantial interfacial pressure between the accessory and the