Impact of ZnO nanoparticle morphology on relaxation and transport properties of PLA nanocomposites

Abstract

In this work we study the effect of zinc oxide (ZnO) nanoparticle morphology and concentration on the resulting relaxation and transport properties of polylactide (PLA) nanocomposites. Films containing spherical and rodshaped ZnO nanoparticles were incorporated into an amorphous polylactide (PLA) matrix through a solventprecipitation and compression moulding method. Morphological analyses carried out by scanning electron microscopy (SEM) together with ultraviolet-visible (UV-Vis) spectroscopy and thermogravimetric analysis (TGA). Results indicate a much better distribution of rod-shaped ZnO within PLA matrix. Relaxation experiments reveal faster physical aging kinetics of PLA in presence ZnO nanoparticles notwithstanding their shape, suggesting the presence of non-interacting surfaces between the amorphous PLA matrix and the ZnO nanoparticles. Interestingly, both helium and oxygen permeability remained stable or increase upon nanoparticle addition, and anisole sorption kinetics showed faster mass transport in the nanocomposites, suggesting that the low interfacial adhesion between PLA and ZnO brings supplementary voids to the material increasing mass transport. Overall, the experimental findings here reported provide a deeper understanding on the influence of metal oxide nanoparticle morphology on the resulting relaxation and gas transport properties of amorphous polymeric nanocomposites.

Effect of Zinc Oxide Nanoparticles on the Thermal, Mechanical and Water Absorption Properties of Polylactic Acid/Chitosan Composites

“…Pure PLA has a tensile strength of 13 MPa and declined after added chitosan. However, the addition of ZnO nanoparticles has further increased tensile strength as reported in previous studies [30]. PLCHZa with 2 wt% of ZnO nanoparticles is the most significant variation value tensile strength of 15 MPa compared with PLCHZb and PLCHZc with a tensile strength of only 11.5 and 12 MPa, respectively.…”

“…Subsequently a solution are casted evenly on Petri dish a thickness of about 0.1 mm and dried for 24 in order to evaporate the chloroform as solvent. It was followed by the formation of PLCH wherein 20 grams of PLA film mixed with 5 wt% chitosan by the same method as before using chloroform solvent until all the ingredients are fully soluble, then printed with the same thickness on a baking sheet [30]. Likewise, the variated PLCHZa, PLCHZb, PLCHZc samples (2 wt%, 3 wt% and 4 wt% of ZnO nanoparticles, respectively) are carried out through the same method as the previous step in the same solvent (choloform), same filler (chitosan) and ZnO as the support material based on each the samples concentration.…”

Active Role of ZnO Nanorods in Thermomechanical and Barrier Performance of Poly(vinyl alcohol-co-ethylene) Formulations for Flexible Packaging

“…The marked decrease in thermal stability upon ZnO loading arises from the fact that, as other metal such as Al, Sn and ZnO catalyzes EVOH depolymerization and this effect is much more marked in the case of nanocomposite containing rod-shaped NPs, as already observed by Lizundia et al [57]. Due to the fact that the catalytic reactions take place at the ZnO interfaces, the amount of ZnO-EVOH interfaces would determine the thermal degradation behavior of nanocomposites.…”

Effect of ultrahigh‐pressure treatment on the functional properties of poly(lactic acid)/ZnO nanocomposite food packaging film

“…PLA has some disadvantages in terms of functionality compared to petroleum‐based polymers used as food packaging, such as poor gas barrier property, 7 relatively poor mechanical performance 8 and poor thermal properties 4–6 . In this regard, a typical approach is to blend PLA with metal nanoparticles like silver, 10–12 titanium 13 and zinc 7–12 . Zinc oxide (ZnO) nanoparticles have some excellent properties, such as non‐toxicity, low cost, stability and strong antimicrobial activity 13–15 .…”