Search results for "Halloysite"
showing 10 items of 185 documents
Effect of the supramolecular interactions on the nanostructure of halloysite/biopolymer hybrids: A comprehensive study by SANS, fluorescence correlat…
2020
The structural properties of halloysite/biopolymer aqueous mixtures were firstly investigated by means of combining different techniques, including small-angle neutron scattering (SANS), electric birefringence (EBR) and fluorescence correlation spectroscopy (FCS). Among the biopolymers, non-ionic hydroxypropylcellulose and polyelectrolytes (anionic alginate and cationic chitosan) were selected. On this basis, the specific supramolecular interactions were correlated to the structural behavior of the halloysite/biopolymer mixtures. SANS data were analyzed in order to investigate the influence of the biopolymer adsorption on the halloysite gyration radius. In addition, a morphological descript…
Composite films of natural clay nanotubes with cellulose and chitosan
2014
Composite films based on cellulose, chitosan and halloysite clay nanotubes were prepared using a solution casting method, which allowed for a uniform distribution of nanotubes within the material and provided control over the morphology of the composite. The mechanical performance of these bio nanocomposites is influenced by humidity and the nanotubes showed a plasticisation effect on the polymeric matrix. The composites of chitosan and halloysite nanotubes (HNTs), with modified hydrophobic inner lumens, resulted in a technique for controlled and sustainable surface cleaning. Lignocellulose wood microfibres modified with HNTs were also produced by a layer-by-layer assembly. The obtained ma…
Colloidal stability and self-assembling behavior of nanoclays
2020
Abstract Currently, nanoclays are attracting the attention of a wide part of the scientific community, due to some of their most peculiar features that make them good candidates for applications in different fields. In light of this, some strategies can be pursued in order to obtain stable colloidal dispersions of nanoclays with the aim to improve their features and to expand their use. Hence, this chapter presents an overview on the structural and morphological characteristics, the physico-chemical properties and the main approaches that are taken into account for the preparation of homogeneous suspensions of Halloysite, Imogolite and Laponite in both aqueous and apolar solvent media. In p…
Films of Halloysite Nanotubes Sandwiched between Two Layers of Biopolymer: From the Morphology to the Dielectric, Thermal, Transparency, and Wettabil…
2011
This study focused on the preparation and characterization of films based on biopolymers (hydroxypropylcellulose and low methoxyl pectin) and halloysite nanotubes (HNTs). The morphology is strongly dependent on the polymer nature. In particular, we observed a sandwich-like structure composed of two hydroxypropylcellulose layers incorporating the HNTs and a homogeneous distribution of the nanotubes into the low methoxyl pectin matrix. The different mesoscopic properties were invoked to explain the dielectric, thermal, and wettability properties of the corresponding films. Nanocomposites obtained by combining materials from renewable resources and HNTs is a challenging task in view of designi…
Effect of the Biopolymer Charge and the Nanoclay Morphology on Nanocomposite Materials
2016
This work represents a contribution to the design, preparation, and characterization of nanocomposite materials based on biocompatible components. The effects of composition, filler geometry, and polymer charge were highlighted, and their role on the final properties of the nanocomposites was revealed. We combined some biopolymers (methylcellulose, alginate, chitosan) with two nanoclays (kaolinite sheets and halloysite nanotubes) to prepare nanocomposites by means of the casting method from water. The thermal stability, the surface wettability, and the mechanical properties of the obtained films were studied. SEM micrographs highlighted the surface morphology of the biocomposite materials. …
Halloysite nanotubes as polyolefin fillers
2015
Artykuł stanowi przegląd najnowszej literatury dotyczącej nanokompozytów poliolefinowych napełnianych nanorurkami haloizytowymi (HNT). Omówiono wpływ dodatku HNT na osnowę poliolefinową, ze szczególnym uwzględnieniem morfologii oraz właściwości mechanicznych nanokompozytów poliolefina/HNT. Modyfikowane HNT wykazywały wysoki stopień rozproszenia w osnowie poliolefinowej, dzięki czemu powodowały poprawę właściwości mechanicznych poliolefinowych nanokompozytów napełnianych nanorurkami haloizytowymi. Połączenie korzystnych właściwości poliolefin, ekonomicznych metod ich przetwórstwa oraz unikatowych w³aoeciwooeci HNT pozwoli na szersze rozpowszechnienie nanokompozytów wytworzonych z ich udziałe…
Functionalized halloysite multivalent glycocluster as a new drug delivery system.
2020
A new design for halloysite nanotube materials was obtained by grafting chemically modified cyclodextrin units onto the nanotube surface. In particular, grafted cyclodextrins were decorated with thiosaccharide pendants, in order to mimic the well-known binding of sugars to proteins and the glyco-cluster effect occurring during cellular recognition events. The obtained materials were characterized by using a combination of varied techniques (FT-IR spectroscopy, thermogravimetric analysis, scanning electron microscopy, dynamic light scattering, turbidimetry), and their potential drug-delivery abilities were tested by studying their interactions with the common naturally occurring anticancer a…
Sustainable nanocomposites based on halloysite nanotubes and pectin/polyethylene glycol blend
2013
Abstract This study was focused on the preparation and characterization of biofilms based on pectin/polyethylene glycol 20000 (PEG) blend and halloysite nanotubes (HNTs). The obtained blends loaded with a natural nanoclay are proposed as sustainable alternative to the polymers produced from non-renewable resources such as fossil fuels. Properties of technological interest have been monitored and they were correlated to the structural features of the nanocomposites. It turned out that the wettability of the films can be tuned by changing the composition and the distribution of HNTs into the material as well as the surface roughness. The tensile properties of the blend are enhanced by the pre…
ChemInform Abstract: Eco-Friendly Functionalization of Natural Halloysite Clay Nanotube with Ionic Liquids by Microwave Irradiation for Suzuki Coupli…
2014
Abstract Microwave assisted halloysite (HNT) external surface functionalization with ionic liquids is described. HNTs modification was achieved in two steps: a) grafting of 3-mercaptopropyl trimethoxysilane on the external surface of HNT by a microwave irradiation; b) anchorage of vinylimidazolium ionic liquids by a thiol-ene reaction. MW irradiation allowed us to obtain high loading onto the HNT surface compared to those obtained through conventional synthesis. Fourier transform infrared spectroscopy and thermogravimetric analysis confirmed that the grafting has occurred only on the external surface of HNT. Turbidimetric and dynamic light scattering analyses showed that the introduction of…
Eco-friendly functionalization of natural halloysite clay nanotube with ionic liquids by microwave irradiation for Suzuki coupling reaction
2014
Abstract Microwave assisted halloysite (HNT) external surface functionalization with ionic liquids is described. HNTs modification was achieved in two steps: a) grafting of 3-mercaptopropyl trimethoxysilane on the external surface of HNT by a microwave irradiation; b) anchorage of vinylimidazolium ionic liquids by a thiol-ene reaction. MW irradiation allowed us to obtain high loading onto the HNT surface compared to those obtained through conventional synthesis. Fourier transform infrared spectroscopy and thermogravimetric analysis confirmed that the grafting has occurred only on the external surface of HNT. Turbidimetric and dynamic light scattering analyses showed that the introduction of…