Development of Novel Thin Polycaprolactone (PCL)/Clay Nanocomposite Films with Antimicrobial Activity Promoted by the Study of Mechanical, Thermal, and Surface Properties.

Sylva Holešová,Michaela Ščuková,Marianna Hundáková,Bożena Gzik-Zroska,Karla Čech Barabaszová,Kamila Hrabovská,Kamil Joszko,Magdalena Antonowicz

doi:10.3390/polym13183193

Abstract

Infection with pathogenic microorganisms is of great concern in many areas, especially in healthcare, but also in food packaging and storage, or in water purification systems. Antimicrobial polymer nanocomposites have gained great popularity in these areas. Therefore, this study focused on new approaches to develop thin antimicrobial films based on biodegradable polycaprolactone (PCL) with clay mineral natural vermiculite as a carrier for antimicrobial compounds, where the active organic antimicrobial component is antifungal ciclopirox olamine (CPX). For possible synergistic effects, a sample in combination with the inorganic antimicrobial active ingredient zinc oxide was also prepared. The structures of all the prepared samples were studied by X-ray diffraction, FTIR analysis and, predominantly, by SEM. The very different structure properties of the prepared nanofillers had a fundamental influence on the final structural arrangement of thin PCL nanocomposite films as well as on their mechanical, thermal, and surface properties. As sample PCL/ZnOVER_CPX possessed the best results for antimicrobial activity against examined microbial strains, the synergic effect of CPX and ZnO combination on antimicrobial activity was proved, but on the other hand, its mechanical resistance was the lowest.

Highlights

Polycaprolactone (PCL) belongs to the aliphatic polyesters group, which have been the subject of increasing focus due to their biodegradability and biocompatibility [1]
Novel thin PCL nanocomposite films with antimicrobial nanofillers based on vermiculite, ciclopirox olamine and zinc oxide (ZnO) were prepared
The X-ray diffraction (XRD) and FTIR analyses confirmed the successful intercalation of antimicrobial compounds into the vermiculite structure, with a more regular arrangement of ciclopirox olamine (CPX) in the case of the ZnOVER_CPX sample, due to the lower water content of the initial ZnOVER caused by its calcination

Summary

Introduction

Polycaprolactone (PCL) belongs to the aliphatic polyesters group, which have been the subject of increasing focus due to their biodegradability and biocompatibility [1]. PCL plays an important role in the field of biodegradable and antimicrobial polymeric food packaging materials because of the increasing awareness of environmental problems with plastic waste [18,19,20,21]. The presence of repeating units of nonpolar methylene groups in its structure leads to properties typical for polyolefins, but on the other hand, the ester linkage causes its degradability. Its chemical structure is behind its good miscibility with other polymers, with numerous applications in the biomedical field [1]. PCL possesses some drawbacks, such as insufficient mechanical properties, lower barrier properties to gases, or low thermal stability, as well as a lack of bioactivity and low antimicrobial activity, which could be a limitation for many applications

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