Effects of Ultrasonication Time on the Properties of Polyvinyl Alcohol/Sodium Carboxymethyl Cellulose/Nano-ZnO/Multilayer Graphene Nanoplatelet Composite Films.

Tengteng Ji,Dur E Sameen,Saeed Ahmed,Suqing Li,Xiaorong Dong,Yaowen Liu,Rong Zhang

doi:10.3390/nano10091797

Tengteng Ji, Dur E Sameen + Show 5 more

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https://doi.org/10.3390/nano10091797

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Abstract

Ultrasonication-assisted solution casting was used to prepare polyvinyl alcohol (PVA)/sodium carboxymethyl cellulose (CMC)/nano-ZnO/multilayer graphene nanoplatelet (xGnP) composite films; the performances (mechanical properties, water vapor permeability (WVP), biodegradability and antibacterial activity) of these films were investigated as a function of the ZnO NPs:xGnP mass ratio and ultrasonication time. Intermolecular interactions among ZnO NPs, xGnP and the PVA/CMC matrix were shown to improve WVP, while X-ray diffraction and scanning electron microscopy analyses revealed that the internal reticular structure of ultrasound-treated PVA/CMC/ZnO NPs/xGnP composite films was in a fluffier state than that of the untreated composite films and the PVA/CMC film. The incorporation of ZnO NPs and xGnP into the composite film reduced its tensile strength and elongation at break, and increased antibacterial activity and biodegradability. In addition, we carried out the experiment of strawberry preservation and measured weight loss ratio, firmness, content of total soluble solids and titration acid. Finally, the composite film of 7:3 had the best preservation effect on strawberries. Thus, the obtained results paved the way to develop novel biodegradable composite films with antimicrobial activity for a wide range of applications.

Highlights

Nowadays, most food packaging materials mainly consist of petrochemical-based polymers because they are convenient, low-cost and have excellent barrier performances [1]
All films were wrinkled when they came into contact with water, and the most severe degree of shrinkage was seen with the polyvinyl alcohol (PVA)/carboxymethyl cellulose (CMC) film
PVA/CMC/ZnO NPs/xGnP composite films were successfully fabricated by ultrasonication and solution casting, and showed the best overall performance

Summary

Introduction

Most food packaging materials mainly consist of petrochemical-based polymers because they are convenient, low-cost and have excellent barrier performances [1]. PVA is a non-toxic, highly crystalline and water-soluble polymer that has good film-forming and high hydrophilic properties [2]. Pure PVA/CMC composite films feature low water resistance and have no resistance to pathogens. Zhong et al [7] attempted to fabricate a multi-functional ZnO NPs/CS composite with enhanced biosafety in an efficient and low-cost way, which has potential applications as an antibacterial, UV-shielding or dye water-treatment agent. ZnO NPs possess many advantages, such as being non-toxic, allowing cheap and easy synthesis of semiconductor materials, having high photocatalytic activity, good chemical stability and resistance to light corrosion, and are doped, and so on [9], whereas their mechanical properties experience deterioration due to the NP surface effect and interfacial action [9]

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