Crosslinking of rotational molding foams of polyethylene

• Published in: Polymer engineering and science 2007-11, Vol.47 (11), p.1804-1812
• Main Authors: Marcilla, A., García-Quesada, J.C., Ruiz-Femenia, R., Beltrán, M.I.
• Format: Article
• Language: English
• Subjects: Applied sciences; Cellular; Chemical properties; Crosslinked polymers; Crosslinking polymerization; Exact sciences and technology; Forms of application and semi-finished materials; Materials science; Methods; Peroxides; Plastic foams; Polyethylene; Polymer industry, paints, wood; Polymer melt processing; Properties; Technology of polymers; Vinyl polymers
• ISSN: 0032-3888; 1548-2634
• DOI: 10.1002/pen.20880

Rotational molding of foamed polyethylene has increasingly become an important process in industry due to its ability to produce innovative and high added value parts with little specialist equipment required. The polyolefin foam production tends to achieve the highest possible cell size uniformity and cell size reduction. To improve the cell morphology of the PE foams, the cell coalescence and coarsening might be suppressed, which can be accomplished preserving the melt strength of the polymer during processing. With this aim, in this work two peroxides have been used to enhance the melt strength of a linear low‐density polyethylene by chemical crosslinking. The moldings have been processed at different oven residence times and they have been characterized according to their density, gel content, bubble size distribution and impact strength. Despite the lower crosslinking degree attained by the crosslinked foams, the results show an enhancement in the cell morphology of these moldings, which are able to keep their cell size distribution even with the longest processing times and consequently the processing window of these rotational molding foams is widened. POLYM. ENG. SCI., 47:1804–1812, 2007. © 2007 Society of Plastics Engineers