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Nanoengineered Eggshell–Silver Tailored Copolyester Polymer Blend Film with Antimicrobial Properties
journal contribution
posted on 2017-02-16, 00:00 authored by Boniface
J. Tiimob, Gregory Mwinyelle, Woubit Abdela, Temesgen Samuel, Shaik Jeelani, Vijaya K. RangariIn
this study, the reinforcement effect of different proportions
of eggshell/silver (ES-Ag) nanomaterial on the structural and antimicrobial
properties of 70/30 poly(butylene-co-adipate terephthalate)/polylactic
acid (PBAT/PLA) immiscible blends was investigated. The ES-Ag was
synthesized using a single step ball milling process and characterized
with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS),
and transmission electron microscopy (TEM). These results confirmed
the existence of silver nanoparticles (Ag NPs) in the interstitial
spaces of the eggshell particles. The thin films in this study were
prepared using hot melt extrusion and 3D printing for mechanical and
antimicrobial testing, respectively. These films were also characterized
by thermogravimetric analysis (TGA), differential scanning calorimetry
(DSC), scanning electron microscopy (SEM), XRD, tensile testing, and
antimicrobial analysis. It was found that the incorporation of ES-Ag
(0.5–2.0% content) compromised the tensile properties of the
blend, due to poor interaction between the matrix and the ES-Ag in
the ternary systems, but thermal analysis revealed improvement in
the onset of degradation temperature and char yield at 500 °C.
Though film toughness was better than that of PLA, the strength was
lower, yet synergistic to those of PBAT and PLA. In general, the PBAT/PLA/ES-Ag
ternary system had properties intermediate to those of the pure polymers. In vitro assessment of the antimicrobial activity of these
films conducted on Listeria monocytogenes and Salmonella Enteritidis bacteria revealed
that the blend composite films possessed bacteriostatic effects, due
to the immobilized ES-Ag nanomaterials in the blend matrix. Atomic
absorption spectroscopy (AAS) analysis of water and food samples exposed
to the films showed that Ag NPs were not released in distilled water
and chicken breast after 72 and 168 h, respectively.