Key Benefits
Mechanical Property Improvements
The tensile strength, elongation to break, Young’s modulus, and Shore A Hardness were all improved with the addition of 1.0% halloysite to an MDI polyurethane system.
| Neat MPU | 10.4 | 272 | 15.2 | 92 |
| 0.5% Halloysite | 21.7 | 365 | 21.4 | 92 |
| 1% Halloysite | 22.9 | 347 | 21.5 | 94 |
| 5% Halloysite | 21.1 | 278 | 48.2 | 97 |
Gong, B., Ouyang, C., Yuan, Y., & Gao, Q. (2015). Synthesis and properties of a millable polyurethane elastomer with low halloysite nanotube content. RSC Adv., 5(94), 77106–77114.
Polyurethane / Halloysite Crosslinked Network
Fracture Toughness Improvements
The fracture toughness of the halloysite particle modified epoxies was noticeably increased, with the greatest improvement in KIC up to 50% and in GIC up to 127%. The improvements in fracture toughness are mainly attributable to mechanisms such as crack bridging, deflection and plastic deformation of the epoxy around the particle clusters.The fracture toughness of the halloysite particle modified epoxies was noticeably increased, with the greatest improvement in KIC up to 50% and in GIC up to 127%.
The improvements in fracture toughness are mainly attributable to mechanisms such as crack bridging, deflection and plastic deformation of the epoxy around the particle clusters.
Deng, S., Zhang, J., Ye, L., & Wu, J. (2008). Toughening epoxies with halloysite nanotubes. Polymer, 49(23), 5119–5127.
CTE and Mechanical in Glassy and Rubbery States Improvement
Halloysite was incorporated in a cyanate ester cured epoxy resin to lower the CTE value and increase the mechanical properties of the epoxy resin.
| Sample (wt%) | E’ at 50C (Mpa) | Increase (%) | E’ at 210C (Mpa) | Increase (%) |
| Neat Resin | 2701 | 62.8 | ||
| 4% Halloysite | 3354 | 24.2 | 88.1 | 40.3 |
| 8% Halloysite | 3491 | 29.2 | 109.7 | 74.7 |
| 12% Halloysite | 4283 | 58.6 | 139.2 | 121.7 |
Liu, M., Guo, B., Du, M., Cai, X., & Jia, D. (2007). Properties of halloysite nanotube– epoxy resin hybrids and the interfacial reactions in the systems. Nanotechnology, 18(45), 455703.
Impact Strength Improvements
The impact strength of the halloysite particle modified epoxies was noticeably increased 400% without sacrificing other mechanical properties. The underlying toughening mechanisms responsible for the unusual 400% increase in impact strength were investigated and identified as massive micro-‐cracking, nanotube bridging/pull out/breaking and crack deflection.
Ye, Y., Chen, H., Wu, J., & Ye, L. (2007). High impact strength epoxy nanocomposites with natural nanotubes. Polymer, 48(21), 6426–6433.
Flexural Strength and Modulus Improvement
Halloysite was incorporated in a cyanate ester cured epoxy resin to increase the flexural strength and modulus.
Flexural Modulus and Flexural Strength of Epoxy/Halloysite Nanocomposites
| Sample (wt%) | Flexural Strength (Mpa) | Flexural Modulus (Gpa) |
| Neat Resin | 47 | 3.26 |
| 4% HNTs | 100 | 3.65 |
| 8% HNTs | 107 | 3.85 |
| 12% HNTs | 91 | 3.98 |
Liu, M., Guo, B., Du, M., Lei, Y., & Jia, D. (2008). Natural inorganic nanotubes reinforced epoxy resin nanocomposites. Journal of Polymer Research, 15(3), 205–212.
Fracture and Impact Toughness Improvements
The impact strength of the halloysite particle modified epoxies was noticeably increased 400% without sacrificing other mechanical properties. The underlying toughening mechanisms responsible for the unusual 400% increase in impact strength were investigated and identified as massive micro-‐cracking, nanotube bridging/pull out/breaking and crack deflection.
Fracture Properties of VER and VER/ Halloysite Nanocomposites
| Sample (wt%) | Fracture Toughness (Mpa m1/2) | Impact Toughness (kJ/m²) |
| Neat VER | 1.8 | 1.5 |
| 1% Halloysite | 2.1 | 2.9 |
| 3% Halloysite | 2.4 | 3.3 |
| 5% Halloysite | 2.6 | 4.1 |
Alhuthali, A., & Low, I. M. (2013). Mechanical and fracture properties of halloysite nanotube reinforced vinyl-ester nanocomposites. Journal of Applied Polymer Science, 130(3), 1716–1725.
SEM Images of VER/ Halloysite Samples
a. VER resin
b. VER/1%HNT loading
c. VER/3% loading d. VER/5%HNT loading
The elastomers market is the largest single user of high performance fillers like carbon black and silica ($5 Billion USD annually). High surface area grades are used as these facilitate processing of the elastomers and also raise the mechanical properties.
DRAGONITE, as a high surface area silicate type filler, would be expected to show promise in elastomeric systems and that has indeed been found to be the case.
The advantages of DRAGONITE in elastomers include:
Incorporation into EPDM (at 100 phr)
Morphological, thermal and tensile propertes of halloysite nanotubes filled ethylene propylene diene monomer (EPDM) nanocomposiles, H. Ismail, Pooria Pasbakhsh, M.N. Ahmad Fauzi, A. Abu Bakar, Polymer Testing 27: 841-850 (2008).
Incorporation into Natural Rubber
The advantages of DRAGONITE in fluoroelastomers include:
| Material | 100% Modulus (MPa) | (E'0 - E') Modulus (MPa) | Tensile Strength (MPa) | Elongation to Break (%) |
| FKM gum | 2.5 | 7.45 | 4.5 | 197 |
| +5 phr Halloysite | 3.0 | 8.50 | 6.2 | 217 |
| +10 phr Halloysite | 3.4 | 13.91 | 6.8 | 205 |
| +20 phr Halloysite | 3.6 | 15.48 | 7.3 | 200 |
| +30 phr Halloysite | 2.6 | 11.97 | 5.6 | 254 |
Tube-like natural halloysite/fluoroellastomer nanocomposites with simultaneous enhanced mechanical, dynamic mechanical and thermal properties, S. Rooj. A. Das, G. Heinrich, European Polymer Journal doi: 10.1016/j.eurpolymj.2011.06.007.
The superior performance seen in thermoplastics and elastomers is mirrored in thermoset materials. In epoxy resins, numerous articles have reported excellent results. Halloysite improves modulus and strength as one would expect for a high aspect ratio filler. Just 5 weight % Halloysite improved the interlaminar shear strength (ILSS) by 25% in carbon fiber reinforced Epon Resin 828 cured with MDA. Toughness was significantly improved at the same time.
| Property | Neat Epoxy | 5% Halloysite | 10% Halloysite |
| Flexural Modulus (GPa) | 3.05 | 3.39 (+11%) | 3.59 (+18%) |
| Flexural Strength (MPa) | 110 | 116 (+16%) | 120 (+20%) |
| K1C(MPa.m1/2) | 0.90 | 1.26 (+40%) | 1.35 (+50%) |
| G1C(MPa.m1/2) | 228 | 456 (+100%) | 517 (+127%) |
K1C - Critical stress intensity factor (energy needed to initiate a crack)
G1C - Critical strain energy release rate (energy needed to grow a crack)
Toughening epoxies with haloysite nanotubes S. Deng, J. Zhang. L Ye, J. Wu. Polymer. 49. 5119-5127 (2008).
In another study, adding just 2.3 weight % Halloysite improved impact resistance by an astonishing 400%. These benefits are of particular interest in the aerospace industry where light, durable carbon fiber reinforced epoxies dominate.
High impact strength epoxy nanocomposites with natural nanotubes Y. Ye, H. Chen, J.Wu,L.Ye, Polymer, 48: 6426-6433 (2007).
DRAGONITE improves the properties of rigid PVC. Again, true reinforcement is seen as evidenced by an increase in both strength and stiffness. Even more impressive is that no loss in either impact resistance or elongation to break is seen. In fact, the virgin PVC failed in a brittle mode whereas all samples with DRAGONITE added became ductile.
| Property | PVC | 1% Dragonite | 2% Dragonite | 3% Dragonite |
| Flex Modulus (kpsi) | 459 | 490 | 488 | 521 |
| Flex Yeild Strength (psi) | 13084 | 13771 | 13834 | 14010 |
| Elongation to Break (%) | 6 | 10 | 9 | 8 |
| Notched Izod (ft-lb/in) | 0.9 | 0.9 | 0.9 | 0.9 |
| unnotched Izod (ft-lb/in) | 7.3 | 7.2 | 10.2 | 12.5 |
DRAGONITE has also proven effective in a wide range of other polymers including PET, PBT, Nylon 12 and PEEK.
DRAGONITE is a natural material that allows for reduced energy consumption during part production as well as reduced plastics use through thin-walling enabled by the mechanical property improvements.
DRAGONITE is also recyclable. Customers are aware that fillers are often broken down during recycling operations whereby the extruder damages the particles and the mechanical properties fade with each successive recycling operation. A study using multiple successive extruder passes showed that DRAGONITE enables property retention when recycling because the particles are simply too small to be broken down by extrusion.
