230 Irradiation processing in the production of low density, crosslinked cellular plastics
11:25 - 11:45 Tuesday 23 September | Advanced Materials 2: Facilities Processing and Equipment
Paul Jacobs and Neil Witten: Zotefoams plc, UK
E-Mail: pmj@zotefoams.com
Abstract
Zotefoams plc is the worlds leading manufacturer of low density, closed-cell crosslinked block foams and is recognised globally for producing the highest performance polyolefin foams. In recent years, the company has developed a new generation of low density crosslinked foams based on materials where foaming to low densities has traditionally been an insurmountable technical challenge. Using the unique processing technology employed by Zotefoams plc, foams of the fluoropolymer Polyvinylidene Fluoride (PVDF) and the polyamide Polyamide 6 (PA6) have been produced.
In these materials, irradiation is the method of choice to crosslink the polymer and, thereby, achieve the required melt strength for expansion and control of the foam structure. The crosslinking stage is highly critical to the foam processing and either electron beam or gamma irradiation may be selected depending on a number of factors related to the material to be expanded.
This paper will briefly describe the unique foaming technology used by Zotefoams plc and reflect upon the importance of the crosslinking stage to the final product. Key points will be raised with relation to the polymer type, physical dimensions and the sensitivity of the final foam properties to the irradiation process. The ability of the foaming process to highlight effects related to the irradiation process that might otherwise be hidden in the solid polymer will also be discussed.