Halloysite

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Halloysite, a naturally occurring aluminosilicate nanotube, has been undeservedly under utilized by many industries. Halloysite (Al2Si2O5(OH)4•2H2O) is a two-layered aluminosilicate,  with many unique properties and with a predominantly hollow tubular structure in the submicron range and chemically similar to kaolin.  Halloysite is an economically viable material that can be mined  as a raw mineral.  As with most natural materials there is variation. The size of halloysite particles varies between 1-15 microns of length and .0 1-.15 microns inner diameter.

TUBULAR HALLOYSITE IS A NON-TOXIC NATURALLY OCCURRING MATERIAL THAT HAS RECEIVED U.S. GOVERNMENT  FDA APPROVAL FOR A WIDE VARIETY OF USES.

NORTHSTAR TUBULAR HALLOYSITE CAN BE UTILIZED TO MAKE PRODUCTS BETTER IN:


PHARMACUTICALS
          Time-controlled release of active ingredients;

PAINTS & COATINGS
          Controlled release of pesticides and antifungal ingredients;

COSMETICS
          Time-controlled release of fragrances, stabilization of  pigmentation, and provides moisture retention;

PLASTICS
          Strengthens plastic products by polymer reinforcement while reducing weight.


 (SpecialChem Report) Growing use of antimicrobials

SpecialChem - Jun 2, 2010
The growing use of polymers in the healthcare market is often said to lead the growing use of antimicrobials in the coming years. Another strong driver that is commonly accepted from the latest publications is telling that hospitals-acquired infections (with the well-known nosocomial infections) is pushing even further for an increased use of antimicrobials in medical applications. Looking into more details allows a fine-tuning of these above statements: our society is more and more looking at the single failures of its processes, and when it deals with health “failures” means death risk. It is not so much a question of increased hospitals-acquired infections, but more probably a question of psychological refusal of leaving room for growth to microbes. And many times ones will see examples of new uses of antimicrobials outside of hospitals.

Halloysite Clay Nanotubes

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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 0.3/0.1 microns outer/inner diameter. Aggregates of microtubules, double tubules and occasional split or partially unrolled tubules were observed  (see halloysite photos page). 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, but larger molecules including the drug, diltiazem HCl, failed to exchange. The surface charge was 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 allophanc 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 as an aid to further formulation development, which rapidly disintegrated in water unless prevented by sintering at 200 °C.

Halloysite

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Northstar Halloysite Nanotubes have an average tube diameter of  .o3 microns and inner diameter of .015 microns. 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.



TYPICAL CHARACTERISTICS

True Specific Gravity:                                 2.53
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                                                   .0 3 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   

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