Halloysite Nanotubes Epoxy NanoComposites

Songshan Zeng Christopher Reyes

Halloysite Nanotubes Epoxy NanoComposites

Songshan Zeng Christopher Reyes

Epoxy Chemistry   Epoxy systems consist of a liquid epoxy resin manufactured

from epichlorohydrin and Bisphenol-F with a cycloaliphatic amine curing agent.

  The curing agent facilitates the opening of the epoxide groups in the epoxy resin which leads to a chain reaction and cross linking.

  Epoxies are used in many applications in various industries

because of their superior mechanical, adhesive, electrical and chemical resistance properties

  EPON™ Resin 862 and EPIKURE™ Curing Agent will be used for all composites.

Chemical model structure and molecule of EPI W Cure1

Chemical model structure and molecule of EPON 8621

Chemical models structure and molecule makeup of EPON62 and EPI W Cure

EPON 862 and Curing Agent Cross-Linked in a Square Configuration2

NanoComposites Introduction   Nanocomposite are composed of two or more materials

which have different physical or chemical properties, with at least one being in the nanometer scale.

  Nanofillers such as halloysite nanotubes, carbon nanotubes, and nano materials are desirable because they have superior physical and chemical properties

  Nano materials are incorporated into the epoxy to exploit their properties.

  All composites in this research will be epoxy based with halloysite nanofillers of various weight proportions.

Halloysite Introduction   Halloysite [Al2(OH)4Si2O5•2H2O] is an inorganic hollow nanotube.   The internal diameter and length of HNTs vary from 15 to 100 nm

and from 0.02 to 2 30 μm, respectively.   The mismatch in the periodicity between the oxygen sharing

tetrahedral SiO4 sheets and adjacent octahedral A1O6 sheets leads to the forming tubular HNTs covered with surface hydroxyl groups.7

  Cite from “Yuan, P.; Southon, P. D.; Liu, Z.; Green, M. E. R.; Hook, J. M.; Antill, S. J.; Kepert, C. J. J. Phys. Chem. C 2008, 112 (40), 15742-15751. “

Crystalline Structure of Halloysite

Halloysite Nanotube Structure

Structure of halloysite monolayer and cross section views of (a) a (12,0) imogolite nanotube and (b) a (12,0) halloysite nanotube. White atoms are H, red O, gray Al, and yellow Si. Luciana Guimara˜es,†,‡ Andrey N. Enyashin,§,| Gotthard Seifert,§ and He´lio A. Duarte*,†Structural, Electronic, and Mechanical Properties of Single-Walled Halloysite Nanotube Models January 30, 2010; Department of Chemistry, ICEx, UniVersidade Federal de Minas Gerais, 31.270-901 Belo Horizonte, MG,Brazil, Department of Natural Science,

SEM images of HNTs

TEM images of HNTs

Images- Newly emerging applications of halloysite nanotubes: a review, Mingliang Du,a,b∗ Baochun Guob∗ and Demin Jiab Published online in Wiley Interscience: 12 January 2010

Recent Work Introduction

1.  Preparation of two pure epoxy samples (labeled as #1epoxy and #2 epoxy )from EPON™ Resin 862 and EPIKURE™ Curing Agent

2.  Purification of Halloysite Nanotubes (HNT)

3.  Preparation of epoxy/neat HNT(weigh ratio= 100:1) nanocomposite

4.  Mechanical test for pure epoxy and nanocomposite

Preparation for #1epoxy sample Resin &

Curing agent weighed,

ratio (24:100)

Each diluted with

acetone and mixed

rotary evaporation in 60℃ at 100 rpm

Pour into a silicon mold

Cured at 80 ℃ for

1.5hrs then at 150 ℃ for

1.5hrs

When free of solvent (about 30mins)

 Problems: Numerous bubble were showed in the samples.

 Reasons: Entrapped gas during mixing and solvent not completely evaporated

  Solutions: Use less solvent and degas the sample in vacuum oven

Problems & solutions for #1epoxy

Preparation for #2 epoxy Resin &

Curing agent weighed,

ratio (24:100)

Each diluted with

acetone and mixed

rotary evaporation in 60℃ at 100 rpm

poured into a silicon

mold

Cured in 80 ℃ for 1.5hrs and then in 150 ℃ for

1.5hrs

Degassed under vacuum oven at 60 ℃ for 2.5 hrs

New Step*

Concerns for #2 epoxy

 1. The 60℃ for degassing process is close to the 80℃for curing with could cause premature cross-linking.

 2. The degassing time should be modified

to a shorter time and a lower temperature.

Preparation for epoxy/n-HNT(100:1)

polymers diluted in

acetone and mixed with

HNT

the mixture sonicated

1 hr

poured into a silicon

mold

Cured in 80 ℃ for 1.5hrs and then in 150 ℃ for

1.5hrs

Degassed at vacuum

oven at 60 ℃ for 1.5

hrs

rotary evaporation in 60℃ at

100 rpm for 30 mins

HNT sonicated 15mins in acetone

Purify HNT and weigh

sample

Concerns for epoxy/n-HNT(100:1)

 The color of mixture is green before curing; pure epoxy is amber.

 Possible reasons, Fe impurities in the HNTs

 Will need to remove Fe impurities

Mechanical Testing of Neat Epoxy

Sensor: 1000 lbs ; Test speed: 5 mm/min Standard: ASTM D 638-03

Sensor: 1000 lbs Test speed: 5mm/min Standard: ASTM D 638-03

*Max should be in the 2000N range

Mechanical Testing of NanoComposite

Sensor: 1000 lbs ; Test speed: 5 mm/min Standard: ASTM D 638-03

Sensor: 1000 lbs Test speed: 5mm/min Standard: ASTM D 638-03

*Max higher than neat as expected but, should also be in the 2000N range

Future Work- HNT modification   HNT surface modification with Silane: 3-aminopropyltriethoxysilane(APTES)

  Once cured, the surface amine (or epoxide) groups on HNTs will be covalently bonded with the epoxy matrix, allowing the HNTs to be integrated into the epoxy network. Such integration will enable the load to be fully transferred to the HNTs… leading to significant stiffness/strength improvement. (Sun, L.; Warren, G. L.; O'Reilly, J. Y.; Everett, W. N.; Lee, S. M.; Davis, D.; Lagoudas, D.; Sue, H. J.

Carbon 2008, 46 (2), 320-328. )

Image- Mingliang Du,a,b∗ Baochun Guob∗ and Demin Jiab/ Newly emerging applications of halloysite nanotubes: a review Published online in Wiley Interscience: 12 January 2010 c 2010 Society of Chemical Industry

Epoxy monomer

HNT Modification Procedure

Cite from “Yuan, P.; Southon, P. D.; Liu, Z.; Green, M. E. R.; Hook, J. M.; Antill, S. J.; Kepert, C. J. J. Phys. Chem. C 2008, 112 (40), 15742-15751. “

2 mL of APTES

dissolved in 25 mL toluene

0.6 g of clay Added to the suspension

refluxed at 120 °C for 20 h

under constant stirring

filtered & washed

six times with resh toluene then dried at 120 °C for 24

hrs

Sonicate for 30min

Future Work - Loading

Nanotubes in Diluted epoxy or curing agent

Vacuum removes air from lumens

When vacuum is broken, epoxy components enter

Acetone washing

Dry loaded Nanotubes

Self-healing implementation upon the rupture of HNTs Above image -Abdullayev, et al.17 copyright 2009

Image-Sun, L.; Warren, G. L.; Davis, D.; Sue, H. J. J. Mater. Sci. 2011, 46 (1), 207-214

Thank You Q & A