Non-crosslinked foams vs. crosslinked foams – properties and differences
Cross-linked foams are manufactured using various methods. These include chemical processes, such as peroxide cross-linking and silane cross-linking, as well as physical methods, such as electron beam cross-linking. The aim in each case is to achieve a closed-cell structure, as this gives PE foam different properties to open-cell foams. The cross-linking of foams influences their pressure and deformation properties, tensile properties, thermal characteristics, water absorption, chemical resistance, weather resistance, and surface structure.
Uncrosslinked and crosslinked – foam properties in comparison
Compressibility (hardness & resilience):
Crosslinked and non-crosslinked foams exhibit different reversible and constant reactions to pressure.
Unlike crosslinked foams, non-crosslinked foams generally only allow limited compression before their cells burst. This means that foam in its non-crosslinked form has a much lower rebound effect and does not return to its original shape.
However, this property is particularly advantageous and desirable for structural packaging. The impact or fall energy is very well absorbed by the bursting of the cells. The part to be protected is thus decelerated more gently and therefore subjected to significantly less mechanical stress – even in many repeated "cases." It therefore cushions the items even when subjected to multiple external impacts, e.g., from a fall. Corrugated cardboard boxes, on the other hand, can only withstand a single external impact. The corrugations collapse and are therefore no longer able to dissipate energy at these points.