What is the benefit of crosslinking a polyethylene?
Crosslinking gives a heat shrink sleeve a memory (and a desire) to return to its original shape. This is how a 2" tube shrinks to a 1"; how a 30" sheet shrinks to a 22" or how a molded part shrinks to its original shape (read more about crosslinking here). In the pipeline coatings world or the electrical splicing world; without shape memory; we would not have a product to sell.
Crosslinking makes the PE (or polyolefin) backing tougher and more abrasion resistant. This is important for buried and subsea pipelines; for high voltage wire insulation and for splicing. In addition, because the PE is more abrasion resistant; a thinner PE jacket can sometimes be used which translates to dramatically less weight on airplanes, automobiles, etc.
Better performance at higher temperatures.
Since the PE no longer melts, it isn't subject to dramatic weakening at higher temperatures (within reason, of course).
Improved chemical resistance.
The crosslinked PE is less susceptible to different chemicals and solvents.
Reduction in gas permeation.
In corrosion prevention, reducing the water vapor transmission is VERY important.
Improved mechanical properties.
Properties like tensile strength, penetration resistance, hot water immersion and others.