Monolithic nanoporous-crystalline aerogels based on PPO

Monolithic and robust aerogels exhibiting nanoporous-crystalline modifications of an industrially relevant polymer (poly(2,6-dimethyl-1,4- phenylene)oxide, generally known as polyphenyleneoxide, PPO), have been obtained from thermoreversible gels, by sudden solvent extraction with supercritical carbon dioxide. The aerogel formation occurs only in the presence of semicrystalline nanofibrils of syndiotactic polystyrene, a polymer presenting molecular miscibility with PPO in the amorphous phase. These mixed monolithic aerogels can present nanoporous-crystalline phases of both polymers and hence are very promising for water and air purification. For instance, the carbon tetrachloride uptake from 10 ppm aqueous solutions can be as high as 19 wt%.