High porosity polyethylene aerogels

Abstract

Monolithic aerogels of high molecular weight polyethylene (Mw= 3x106- 6x106 g/mol) have been prepared by solvent extraction with supercritical carbon dioxide from thermoreversible gels prepared in decalin. These low density and highly porous aerogels present an apparent porosity up to 90%. The aerogel morphology observed by scanning electron microscopy (SEM) is characterized by spherulitic structures being interconnected by fibers. X-ray diffraction experiments show that PE aerogels are highly crystalline with a degree of crystallinity of c.a. 80% and PE chains being packed into the typical orthorombic unit cell. Combined SEM and N2 sorption investigations show that PE aerogels are essentially macroporous with a small amount of mesopores. The oil-sorption performance of polyethylene aerogels has been also evaluated in this study in order to assess a possible use of these materials for oil spillage recovery and results show that aerogel macropores allow a very fast sorption kinetics with a 100% oil weight uptake obtained in less than 1 minute.

Keywords

• polyethylene
• thermoreversible gels, aerogels
• supercritical carbon dioxide
• oil spillage recovery