Novel Thermally Reversible XLPE for Roto Molding

Dr. Miao Miao Xiao

Ingenia Polymers Corp.

Crosslinked polyethylenes (XLPE) demonstrate excellent thermal stability, superior chemical, and stress-crack resistance, while maintaining excellent toughness and durability. XLPEs used in rotational molding are traditionally produced using peroxide crosslinking systems for applications requiring such properties. Despite the advantages of XLPE, its use has come under pressure as it is not readily reprocessible. Unlike linear rotomoldable polyethylenes, conventionally made XLPE cannot be remelted and recycled for high-value use. Defective and post-consumer parts are typically sent to landfills or is pulverized to powder and incorporated into low end applications where it essentially acts as filler. Ingenia has developed a novel, thermally reversible crosslinkable PE (TRXL) compound for roto molding applications. The crosslinked products made with this novel PE compounds maintain the physical property improvements of traditional XLPE but are thermally reprocessible and recyclable. In this presentation, a comparison of the molding behaviour, tensile, Flexure, ESCR, and low temperature impact properties of this novel thermally reversible XLPE with traditional peroxide based XLPE and linear PE is presented.  Conditions for decomposition of the crosslink bonds are presented and reversion to a thermoplastic polyethylene structure is demonstrated through gel analysis and rheology. The thermally reversible XLPE can be reprocessed at 100% rates by single or twin-screw extrusion, injection molded, modified for added value end use applications or otherwise incorporated into polyethylene recycle streams.