Bio-based polyphenol tannic acid as universal linker between metal oxide nanoparticles and thermoplastic polyurethane to enhance flame retardancy and mechanical properties

Nanoparticle modified polymers have promise as hybrid materials that exhibit properties beyond those predicted by mixing law theories. In the case of metal-oxide nanoparticles in a polymer, it is expected that multifunctional properties of the obtained nanocomposite, including dielectric and mechanical, will be dominated by presence of interface rather than predicted by the inherent properties of individual components. This paper will focus on understanding the role of different types of nanoparticles, namely, titania, silica and alumina and a polymer matrix, Polyvinylidene fluoride (PVDF) in affecting the final dielectric and mechanical properties.

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Metal and Metal Oxide Nanoparticles in Caries Prevention: A Review

Nanomaterials ◽

10.3390/nano11123446 ◽

2021 ◽

Vol 11 (12) ◽

pp. 3446

Author(s):

Mohammed Zahedul Islam Nizami ◽

Veena W. Xu ◽

Iris X. Yin ◽

Ollie Y. Yu ◽

Chun-Hung Chu

Keyword(s):

Mechanical Properties ◽

Metal Oxide ◽

Metal Ion ◽

Metal Oxide Nanoparticles ◽

Dental Materials ◽

Caries Prevention ◽

Oxide Nanoparticles ◽

Apatite Formation ◽

Metallic Oxide ◽

Metal Ion Release

Nanoparticles based on metal and metallic oxide have become a novel trend for dental use as they interfere with bacterial metabolism and prevent biofilm formation. Metal and metal oxide nanoparticles demonstrate significant antimicrobial activity by metal ion release, oxidative stress induction and non-oxidative mechanisms. Silver, zinc, titanium, copper, and magnesium ions have been used to develop metal and metal oxide nanoparticles. In addition, fluoride has been used to functionalise the metal and metal oxide nanoparticles. The fluoride-functionalised nanoparticles show fluoride-releasing properties that enhance apatite formation, promote remineralisation, and inhibit demineralisation of enamel and dentine. The particles’ nanoscopic size increases their surface-to-volume ratio and bioavailability. The increased surface area facilitates their mechanical bond with tooth tissue. Therefore, metal and metal oxide nanoparticles have been incorporated in dental materials to strengthen the mechanical properties of the materials and to prevent caries development. Another advantage of metal and metal oxide nanoparticles is their easily scalable production. The aim of this study is to provide an overview of the use of metal and metal oxide nanoparticles in caries prevention. The study reviews their effects on dental materials regarding antibacterial, remineralising, aesthetic, and mechanical properties.

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Hydrophobic and Corrosion Behavior of Sol-Gel Hybrid Coatings Based on the Combination of TiO2 NPs and Fluorinated Chains for Aluminum Alloys Protection

Metals ◽

10.3390/met8121076 ◽

2018 ◽

Vol 8 (12) ◽

pp. 1076 ◽

Cited By ~ 5

Author(s):

Pedro Rivero ◽

Juan Maeztu ◽

Calos Berlanga ◽

Adrian Miguel ◽

José Palacio ◽

...

Keyword(s):

Mechanical Properties ◽

Metal Oxide ◽

Metal Oxide Nanoparticles ◽

Sol Gel ◽

Hybrid Coatings ◽

Metal Alkoxide ◽

Oxide Nanoparticles ◽

Pencil Hardness ◽

Tio2 Nps ◽

Hybrid Matrix

In this work, layers of a sol-gel hybrid matrix doped with metal oxide nanoparticles (TiO2 NPs) have been deposited on flat samples of AA6061-T6 aluminum alloy using the dip-coating technique, with the aim of obtaining coatings with better anti-corrosive and hydrophobic properties. Two different organic modified silica alkoxides, namely 3-(glycidyloxypropyl)trimethoxysilane (GPTMS) and methyltriethoxysilane (MTEOS), have been used for an adequate entrapment of the metal oxide nanoparticles. In addition, a fluorinated metal-alkoxide precursor has also been added to the hybrid matrix in order to improve the hydrophobic behavior. The experimental results corroborate that the presence of these TiO2 NPs play an important role in the development of the sol-gel hybrid coatings. The water contact angle (WCA) measurements, as well as pencil hardness tests indicate that TiO2 NPs make a considerable increase in the resultant hydrophobicity possible, with better mechanical properties of the coatings. The coating thickness has been measured by cross-section scanning electron microscopy (SEM). In addition, a glow discharge optical emission spectroscopy (GD-OES) analysis has been carried out in order to corroborate the adequate entrapment of the TiO2 NPs into the sol-gel coatings. Finally, potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) have been performed in order to evaluate the corrosion resistance of the coatings. All the results provide insights into the efficacy of the developed sol-gel hybrid coatings for anticorrosive purposes with good mechanical properties.

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