Alkoxysilanes can be grafted onto an ethylene homopolymer or copolymer to g
ive a moisture crosslinkable polymer. Moisture crosslinking has many benefi
ts over peroxide- or irradiation-induced crosslinking. Simple, conventional
equipment allows processing with lower capital investment and less manufac
turing space. The moisture crosslinking process permits conventional thermo
plastic processing after the initial grafting process to give greater flexi
bility in the types of applications for this crosslinking technique. In foa
ming processes, silane crosslinking is compatible with most types of conven
tional blowing agents and other additives. The combination of silane crossl
inking with metallocene polyethylene technology has given rise to a broad r
ange of crosslinked polyolefin materials, including flexible, rigid, open,
and closed cell foams. Good quality foams with very low densities, approach
ing 1 lb/ft(3) (16 kg/m(3)), are possible. The advantages of silane crossli
nking technology have opened many new markets for polyethylene foams.