Ethylene vinyl acetate nanocomposites with hybrid silicate nanofillers of destabilized natural and commercial bentonites and organomontmorillonites

Abstract

In this research, the interlayer destabilization process of bentonite was applied to gain a loosely packed, swelled, and disorganized clay layered structure for better polymer intercalation and filler dispersion during the fabrication of ethylene vinyl acetate (EVA) nanocomposites. Three different destabilization methods were applied to natural and commercial bentonites and their effects on swelling and platelets’ ordering of the clays were observed. X‐ray diffraction results suggest that the destabilization process through a combination of pH control and salt addition is more efficient in swelling both types of bentonite clays. This was supported by field emission scanning electron microscopy analysis where smaller, more loosely packed, and uniform platelets were observed due to swelling of both natural and commercial bentonite clays. The “destabilized” bentonites were used as the co‐nanofiller with the organically modified montmorillonite (OMMT) to form hybrid silicate nanofillers for EVA matrix reinforcement. Results show that the “destabilized” natural bentonite (NB) prepared by the combination of pH control and salt addition is most efficient in reinforcing the EVA matrix when combined with the OMMT by achieving 124.9% increment in tensile strength and 190.8% in toughness values. This could be related to the improved dispersion of bentonites upon the destabilization process that allows greater matrix–filler interactions in the nanocomposite system. In summary, the destabilization process through the combination of pH control and salt addition is the promising and practical technique to improve the dispersion of bentonites throughout the EVA matrix. Without the use of expensive and toxic chemicals, it can be adopted as a new approach to swell bentonites for more environmentally friendly nanocomposite technology. J. VINYL ADDIT. TECHNOL., 25:396–411, 2019. © 2019 Society of Plastics Engineers

On the Use of OPEFB-Derived Microcrystalline Cellulose and Nano-Bentonite for Development of Thermoplastic Starch Hybrid Bio-Composites with Improved Performance

“…The disappearance of a peak at 1723 cm −1 in the spectrum of the treated cellulose and microcrystalline cellulose samples verifies the removal of hemicellulose and lignin. This is because the presence of lignin and hemicellulose can be detected through the appearance of those peaks due to the functional group of carbonyl ester and the C=O acetyl group of the uronic ester, respectively [ 4 , 8 , 21 ]. In addition, the peak at 1228 cm −1 , which represents the syringyl ring unit and C-O stretching at lignin and xylan, disappeared in the spectra of the treated cellulose, suggesting the removal of lignin and hemicellulose after various treatments [ 15 , 22 ].…”

Biomedical PEVA Nanocomposite with Dual Clay Nanofiller: Cytotoxicity, Mechanical Properties, and Biostability

“…This is because the exposure of Bent to the electrolytic and acidic dispersing environment led to the modification of the Bent's silicate layer arrangement and association. This reduced the interlayer charge and surface energy of the clays to allow improvement in the degree of swelling [19]. As a result, an increment in the basal spacing could be seen.…”

“…This feature promotes the formation of face-to-face platelet stacking (tactoids). The nanoclay is extremely difficult to disperse and align in the host polymer due to the Van der Waals forces that lead to the agglomeration of the nanoclay [19]. In order to allow good nanoclay (S-MMT and Bent) platelet exfoliation and dispersion within the copolymer matrix during the melt compounding process, loosely packed tactoids were the aim.…”