Preparation of Polyethylene/MMT Composites. Clays behaviour as Barrier Properties Modifiers

ERDMANN, E.; DESTÉFANIS, H.A.; MONASTERIO, F.E.; CARRERA, M.C.; ACOSTA, D.E.

Campina Grande, PB - BRASIL

Congreso; CITEM 2007; 2007

Universidade Federal de Campina Grande (UFCG), Laboratório de Referência em Dessalinização (LABDES), COPPE - UFRJ

Barrier properties of high density polyethylene (HDPE)/ modified montmorillonites (MMT) hybrids were studied. An argentinean montmorillonite (MMTAr) was used for preparing two modified clays. The filosilicate was intercalated with e-caprolactam to obtain one kind of organophilic material (MMTArInt). The other modification was introduced by mixing the clay with hexadecyl trimethyl ammonium chloride, a quaternary alkyl ammonium salt (MMTArHDTAM). Cationic exchange was verified by X-ray diffraction (XRD). The melt compounding processing was performed in a mixer chamber. The morphologies of the samples were examined with scanning electronic microscopy (SEM) and the barrier properties with CO2 permeation at 50°C using conventional equipment. Different morphologies are observed from SEM analysis. Composites with MMTAr and MMTArInt show similar structures, these structures are associated to the low chemical affinity between polyethylene – MMT due the polar character of clay. In the other way composites with MMTArHDTAM show higher homogeneity due hydrocarbonated chains of amine. A decreasing of the permeation values were observed in the modified HDPE. Barrier improvement could be associated with the volume free diminution or hook effect resulting due to the clay incorporation. The results show that pristine or modified clay on HDPE/ MMT composites improves barrier properties to CO2.