Search results for "Nanoclay"

Separation of halloysite/kaolinite mixtures in water controlled by sucrose addition: The influence of the attractive forces on the sedimentation beha…

2022

In this work, we propose an easy strategy for the separation of halloysite/kaolinite mixtures in sucrose aqueous solution. Preliminarily, we investigated the influence of the sucrose addition on the colloidal stability of kaolinite nanoplates and halloysite nanotubes (HNTs) dispersed in water. Dynamic Light Scattering (DLS) measurements revealed that the HNTs aqueous mobility is dependent on the sucrose concentration, while the ζ-potential is negligibly affected by the addition of the carbohydrate in the aqueous solvent. On the other hand, any variations on the surface charge and dynamic behavior of kaolinite were detected in the presence of sucrose. The obtained ζ-potential and DLS results…

Gas Barrier, Rheological and Mechanical Properties of Immiscible Natural Rubber/Acrylonitrile Butadiene Rubber/Organoclay (NR/NBR/Organoclay) Blend N…

2020

In this paper, gas permeability studies were performed on materials based on natural rubber/acrylonitrile butadiene rubber blends and nanoclay incorporated blend systems. The properties of natural rubber (NR)/nitrile rubber (NBR)/nanoclay nanocomposites, with a particular focus on gas permeability, are presented. The measurements of the barrier properties were assessed using two different gases—O2 and CO2—by taking in account the blend composition, the filler loading and the nature of the gas molecules. The obtained data showed that the permeability of gas transport was strongly affected by: (i) the blend composition—it was observed that the increase in acrylonitrile butadiene rubber compon…

Bionanocomposite Blown Films: Insights on the Rheological and Mechanical Behavior.

2021

In this work, bionanocomposites based on two different types of biopolymers belonging to the MaterBi® family and containing two kinds of modified nanoclays were compounded in a twin-screw extruder and then subjected to a film blowing process, aiming at obtaining sustainable films potentially suitable for packaging applications. The preliminary characterization of the extruded bionanocomposites allowed establishing some correlations between the obtained morphology and the material rheological and mechanical behavior. More specifically, the morphological analysis showed that, regardless of the type of biopolymeric matrix, a homogeneous nanofiller dispersion was achieved

Dispersions of Nanoclays of Different Shapes into Aqueous and Solid Biopolymeric Matrices. Extended Physicochemical Study

2010

Dispersions of nanofillers into aqueous and solid biopolymeric matrices were studied from the physicochemical viewpoint. This work was carried out based on the idea that the combination of biopolymers, derived from renewable resources, and nanofiller, environmentally friendly, may form a new generation of nanomaterials with excellent and unique properties at low cost. To this purpose, two pectins with different degrees of methyl esterification and nanoclays like halloysite and laponite RD were selected. The thermodynamic and structural studies on the aqueous mixtures of pectin and nanoclay were able to discriminate the interactions, which control the adsorption of pectin onto the filler and…

Filling of Mater-Bi with Nanoclays to Enhance the Biofilm Rigidity

2018

We investigated the efficacy of several nanoclays (halloysite, sepiolite and laponite) as nanofillers for Mater-Bi, which is a commercial bioplastic extensively used within food packaging applications. The preparation of Mater-Bi/nanoclay nanocomposite films was easily achieved by means of the solvent casting method from dichloroethane. The prepared bio-nanocomposites were characterized by dynamic mechanical analysis (DMA) in order to explore the effect of the addition of the nanoclays on the mechanical behavior of the Mater-Bi-based films. Tensile tests found that filling Mater-Bi with halloysite induced the most significant improvement of the mechanical performances under traction force, …

Clay-based drug-delivery systems: what does the future hold?

2017

Clays for drug delivery have been used from ancient time due to the large availability of clay minerals and their unprecedented properties. The empirical use of nanoclays from the past is converted in a stimulating scientific task aimed at building up nanoarchitectonic vehicles for drug delivery in a targeted and stimuli-responsive fashion. Here the historical aspects are discussed; next the modern examples of applications of different clay-based materials are discussed. A special focus is given to halloysite clay nanotubes, which are an emerging and very promising nanomaterial for drug-delivery purposes due to its special morphology and unique chemical properties. Advantages and limitatio…

INTERACTIONS BETWEEN NANOCLAYS AND BIOPOLYMERS EVIDENCED BY EXTENSIVE THERMODYNAMIC AND STRUCTURAL STUDIES

2011

Steric stabilization of modified nanoclays triggered by temperature.

2015

Halloysite clay nanotubes were modified through the adsorption of poly(N-isopropylacrylamide)-amine terminated (PNIPA-NH2) onto the external surface by exploiting electrostatic interactions at pH=6. In spite the amount of attached polymer is rather low (1 wt%), the properties of the nanotubes are deeply modified. The apparent specific volume and isentropic compressibilities of the hybrid nanomaterial dispersed in water evidenced the transferring of the termosensitive property from the polymer to halloysite. The hydrodynamic radius as well as the ζ-potential of the nanohybrid are consistent with the attachment of a positively charged polymer onto the negative surface of the nanotube. The col…

Halloysite Nanotube with Fluorinated Lumen: Non-Foaming Nanocontainer for Storage and Controlled Release of Oxygen in Aqueous Media

2014

Halloysite clay nanotubes were selectivity modified by adsorbing perfluoroalkylated anionic surfactants at the inner surface. The modified nanotubes formed kinetically stable dispersions due to the enhanced electrostatic repulsions exercised between the particles. We proved that the modified nanotubes can be used as non-foaming oxygen nanocontainers in aqueous media. The gas release from supersaturated dispersions can be controlled by external stimuli and system composition. In conclusion, we managed to put forward an easy strategy to develop smart materials from natural nanoclays, which can endow important applications like the storage and delivery of gas.

Pickering Emulsions Stabilized by Halloysite Nanotubes: From General Aspects to Technological Applications

2022

Besides surfactants, which decrease the interfacial tension between two immiscible liquids, also interfacially active particles can successfully stabilize an emulsion system by attaching at the liquid–liquid interface. The preparation of the resulting Pickering emulsions has been so far investigated starting from the study of the interactions arising between the dispersed droplets and the stabilizers, till the application of these systems in a wide range of different fields. This work is intended to provide an overall overview about the development of Pickering emulsions by considering the most general aspects and scanning the diverse types of solid stabilizers. Among them, Halloysite nanot…