Modification of hybrid organic-inorganic porous clay heterostructures for the application in entrapping system

Abstract

Porous clay heterostructures (PCHs) and hybrid organic-inorganic PCHs (HPCHs) were prepared through surfactant-directed assembly of tetraethoxysilane (TEOS) and TEOS/methyltetraethoxysilane (MTS) into the galleries of Na-bentonite clay, respectively. The reaction carried out in the presence of intragallery surfactant templates (cetyltrimethylammonium ion and dedecylamine). Before the synthesis, pH of the bentonite clay was adjusted to 4 conditions including pH 9, 7, 5 and 3. To investigate the formation of porous structures, the products were characterized by N2 adsorption-desorption, XRD, SEM, TEM and FTIR techniques. The results reveal that PCHs have surface areas of 501-668 m2/g, an average pore diameter in the supermicropore to small mesopore range of 3.01-3.85 nm, and a pore volume of 0.43-0.64 cc/g, while HPCHs have a result of 469-582 m2/g, 3.19-3.88 nm, and 0.33-0.49 cc/g, respectively. New applications of the PCHs and HPCHs materials are expected in active packaging for ethylene entrapping system. The ethylene adsorption capacity of these porous clays was investigated using GC. The results reveal that the enhancemence of the hydrophobicity on HPCHs play an important role in ethylene adsorption. Polypropylene/porous clay nanocomposites films were fabricated to thin film by blow film extrusion machine. The nanocomposites wree characterized by using XRD, DSC, and TG-DTA. To investigate gas permeability of PP/PCHs and PP/HPCHs nanocomposite films, these films were measured ethylene permeability and they revealed the possibility of finding a new application for ethylene scavenger films in active packaging.