Halloysite
Scale shown is 1µm (micrometer) which equals 1/1,000,000 of a meter
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Halloysite (Al2Si2O5(OH)4•2H2O) is a two-layered aluminosilicate with a predominantly hollow tubular structure in the submicron range.
This unique material can be utilized by many industries to make products safe for human consumption, cosmetic use, and various high-tech applications (see patent link). These hollow nano-tubes can be loaded (saturated and impregnated) with various active ingredients including pharmaceutical and metal ions. The outside of the tube structure has the protective properties of a silicate, while the inside of the tube structure has the properties of charged aluminum ions, which allows active agents to be attached to the tubes. Halloysite is an economically viable material that can be mined as a raw mineral and that possesses many favorable properties. |
COSMETICS
Halloysite nanotubes (HNTs) can be loaded with moisturizer, fragrances, and other active ingredients for use in cosmetics. Halloysite nanotube powder is completely natural and non-toxic, making it acceptable for use on all skin types. It makes an effective replacement for talcum powder, and has documented applications in a variety of commercial facial masks and gentle exfoliants.
Halloysite fluoresces in long-wave ultraviolet light (which accounts for the majority of UV radiation to reach the Earth's surface. It has been established that Long-wave ultraviolet light initiates the development of skin cancer and plays a major role in premature aging and wrinkles). As such, halloysite is a natural sunscreen. Local research also suggests that finely ground halloysite is effective in reducing wrinkles and aids in removing age spots and excessive oils.
WELLNESS APPLICATIONS
Halloysite has been used as a key ingredient in medicines and pharmaceuticals for hundreds of years. The use of halloysite as a remedy for various bleeding and digestive ailments is well documented historically. Today, halloysite is still in demand throughout the eastern world as a major component to many holistic treatments.
Halloysite has also been the target of close scientific scrutiny. Published observational studies of tubular halloysite confirm the myriad of pharmaceutical applications of halloysite. Halloysite nanotubes have been proven to be effective for the controlled release of active ingredients. Halloysite nanotubes have a much higher carrying capacity under acidic conditions than basic conditions, which makes tubular halloysite a practical solution for release of pharmaceuticals in the human digestive system. Toxicology reports for Halloysite Nanotubes indicate that they are completely safe for human consumption. The low cost, high loading capacity, and availability of Halloysite nanotubes make them an ideal option for many pharmaceutical applications.
PAINTS & COATINGS
Halloysite nanotubes that have been loaded with pesticides and anti-fungal ingredients to create mold-resistant, anti-fouling paints. Halloysite nanotubes have the potential for adding a wide range of active ingredients to high-gloss polymers and paints. The unique crystal shape and high aspect ratio of HNTs add strength, adhesion and impact resistance when used as suspension agents. Halloysite clays "loaded" with ant-fungal ingredients have been shown to eliminate barnacle accumulations on ships and eliminate fungus growth on gypsum wall boards.
NANO-COMPOSITES
When used as a filler, HNTs can be a natural or modified nano-composite. HNTs have a length that is ten times longer than their diameter giving them a high aspect ratio. This provides mechanical strengthening by restrictive matrix dislocation movement. Adding 3% HNTs to plastics improves tensile strength, impact resistance, fire retardance, and gives the added benefit of improved cycling time for manufacturing. HNTs are a nucleating agent that form a skeletal framework for polymers. In their natural state, HNTs are a great filler for ceramics, plastics, and cement. Also, HNTs can be processed for high-tech applications by loading different materials inside the tubes. Loading of metals such as silver or platinum creates a microwave attenuating effect. Loading of active agents inside HNTs has many possibilities. HNTs have a luman (inner tube) diameter of 15nm. Halloysite has a high loading capacity, low cost, and physical properties that make it a superior choice for nano-composites.
Halloysite nanotubes (HNTs) can be loaded with moisturizer, fragrances, and other active ingredients for use in cosmetics. Halloysite nanotube powder is completely natural and non-toxic, making it acceptable for use on all skin types. It makes an effective replacement for talcum powder, and has documented applications in a variety of commercial facial masks and gentle exfoliants.
Halloysite fluoresces in long-wave ultraviolet light (which accounts for the majority of UV radiation to reach the Earth's surface. It has been established that Long-wave ultraviolet light initiates the development of skin cancer and plays a major role in premature aging and wrinkles). As such, halloysite is a natural sunscreen. Local research also suggests that finely ground halloysite is effective in reducing wrinkles and aids in removing age spots and excessive oils.
WELLNESS APPLICATIONS
Halloysite has been used as a key ingredient in medicines and pharmaceuticals for hundreds of years. The use of halloysite as a remedy for various bleeding and digestive ailments is well documented historically. Today, halloysite is still in demand throughout the eastern world as a major component to many holistic treatments.
Halloysite has also been the target of close scientific scrutiny. Published observational studies of tubular halloysite confirm the myriad of pharmaceutical applications of halloysite. Halloysite nanotubes have been proven to be effective for the controlled release of active ingredients. Halloysite nanotubes have a much higher carrying capacity under acidic conditions than basic conditions, which makes tubular halloysite a practical solution for release of pharmaceuticals in the human digestive system. Toxicology reports for Halloysite Nanotubes indicate that they are completely safe for human consumption. The low cost, high loading capacity, and availability of Halloysite nanotubes make them an ideal option for many pharmaceutical applications.
PAINTS & COATINGS
Halloysite nanotubes that have been loaded with pesticides and anti-fungal ingredients to create mold-resistant, anti-fouling paints. Halloysite nanotubes have the potential for adding a wide range of active ingredients to high-gloss polymers and paints. The unique crystal shape and high aspect ratio of HNTs add strength, adhesion and impact resistance when used as suspension agents. Halloysite clays "loaded" with ant-fungal ingredients have been shown to eliminate barnacle accumulations on ships and eliminate fungus growth on gypsum wall boards.
NANO-COMPOSITES
When used as a filler, HNTs can be a natural or modified nano-composite. HNTs have a length that is ten times longer than their diameter giving them a high aspect ratio. This provides mechanical strengthening by restrictive matrix dislocation movement. Adding 3% HNTs to plastics improves tensile strength, impact resistance, fire retardance, and gives the added benefit of improved cycling time for manufacturing. HNTs are a nucleating agent that form a skeletal framework for polymers. In their natural state, HNTs are a great filler for ceramics, plastics, and cement. Also, HNTs can be processed for high-tech applications by loading different materials inside the tubes. Loading of metals such as silver or platinum creates a microwave attenuating effect. Loading of active agents inside HNTs has many possibilities. HNTs have a luman (inner tube) diameter of 15nm. Halloysite has a high loading capacity, low cost, and physical properties that make it a superior choice for nano-composites.
Halloysite Mineral Data
Electron photomicrograph of halloysite nanotubes
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Northstar's Halloysite Nanotubes have an average tube diameter of .03µm (micrometers) and inner diameter of .015µm (micrometers) The typical surface area of halloysite is 65 m2/g, with a pore volume of 1.25 mL/g, index of refraction 1.54, and specific gravity of 2.53 g/cm3
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Halloysite is shown by electron microscopy to be composed mainly of hollow microtubules having typical dimensions of 2-3 microns long and 0.1-0.3 microns outer/inner diameter.
Aggregates of microtubules, double tubules, and occasional split or partially unrolled tubules were observed. The dehydrated state of the mineral was confirmed by XRD analysis, which was partially reversible using a rehydration procedure with subsequent exchange of the intercalated water gained by glycerol. The surface charge is predominantly negative over most of the physiologically relevant pH range (>2) and the specific surface area of the material was very large (57 m2/g), indicating that the material has significant potential for extensive binding of cationic drugs. Removal of allophane present by a hot alkali treatment had little effect on luminal porosity, which prior to treatment was estimated to be 0.25 ml/g by a mercury intrusion technique and consequently should be the major site for drug loading. Halloysite also extruded and spheronised well to form smooth round pellets. |
Halloysite Characteristics
True Specific Gravity: 2.1-2.2 Index of Refraction 1.54 Bulk Density 15.6 lbs./ft3 % linear dry shrinkage 1.01 % linear fired shrinkage (Cone 10) 20.39 % total shrinkage 21.40 Initial pH 6.5-6.9 Oil Absorption (Linseed) 40 lbs/100 lbs Halloysite BHT surface area 64.66 m2/gm BHT pore volume 1.2 - 1.34 ml/gm Carbon Exchange Capacity 8.0 Hunter Brightness (max) 98.4 (+/-) ( iron content) Particle Size (jet milled) Ave 4.7 microns 90% <9.5 microns 100% <36.2 Ave Diameter .03 microns Range of Length 1/2 - 4 microns CHEMICAL ANALYSIS XRF Al2O3 36.9 % SiO2 48.0 % Fe2O3 0.14 % -2.5 % Na2O <0.05 % K2O <0.01 % C2O 0.20 % MgO <0.05 % TiO2 0.04 % LOI 13.8 % |
