property prediction and fabrication of epon 862/w resin

By

Joseph E. Estevez, Mahdi Ghazizadeh, James G. Ryan and Ajit D. Kelkar

Joint School of Nanoscience and Nanoengineering

University of North Carolina at Greensboro and North Carolina A&T University

Nanomaterials WorkshopNational Institute of Aerospace (NIA)

February 21, 2014

Property Prediction and Fabrication of Epon 862/W Resin System with Boron

Nitride Nanotubes

http://jsnn.ncat.uncg.edu/

http://jsnn.ncat.uncg.edu/

Polymer composites

Ceramic composites

Biomedical

Electrically insulating

Radiation shielding

Piezoelectric

Fire retardant cabling

ref: www.bnnt.com

Modeling◦ Predict Young’s Modulus of BNNT◦ Predict and study the effects of Hydrogenation on the

Young’s Modulus of BNNTs◦ Study the interfacial interaction between BNNTs and Epon

862/W resin system◦ Fabrication of Two Phase Composite – Epon 862/W +

BNNTs

Characterization ◦ Structural Characterization of the BNNT’s◦ Glass Transition Temperature

Diethylmethylbenzenediamine(DETDA) “W“

Diglycidyl Ether of Bisphenol F (EPON 862)

Carbon Fiber Epoxy 862/W Resin

Boron Nitride Nanotubes

Built on Newtonian mechanics of molecular material configurations

• Useful tool for materials design• Numerical algorithm solution

schemes are employed• Modeling studies of constituent

material interactions

Mohan et al. SWCM 2012, Kiev 7

Can quickly build systems of molecules or atoms

Great tools for building nanomaterials and altering structures

Multiple modules with detailed force fields for specific systems and applications ◦ Ex. CASTEP, Amorphous

CASTEP can several task:

◦ Single-point energy calculation

◦ Geometry optimization

◦ Molecular dynamics

◦ Elastic constants calculation

# of Atoms 240Lattice parameters

(angstroms) 11.483,11.483,24.595Boron Pink

Nitrogen Blue# of Unit cells 10Estevez et al. AIAA Boston 2013

Theoretical Density of BNNT: ~2.28g/cm3

Presenter

Presentation Notes

Initial example explaining the method based on AIAA paper

# of Atoms 240 240 240 240Lattice

parameters (angstroms) 11.483,11.483,24.595 12.631,12.631,24.595 13.894,13.894,.24.595 15.283,15.283,24.595

# of Unit cells 10 10 10 10# of Atoms 240

Lattice parameters(angstroms) 9.45,9.45,24.59

# of Unit cells 10Estevez et al. AIAA Boston 2013

Presenter

Presentation Notes

Collapse of bnnt during geometry opt and increase of box size

Estevez et al. AIAA Boston 2013

By adding hydrogen to BN materials, it can enhance the radiation shielding capability of the Boron Nitride.

Thibeault et al. NASA Research Center Langley 2009

Thibeault et al. NASA Research Center Langley 2009

1. It is very effective at fragmenting heavy ions such as galactic cosmic radiation (GCR)

2. Stopping protons, which can be found in SPE’s or can be GCRs

3. Good at slowing down high energy neutrons, increasing the effectiveness of boron and its ability to capture neutrons

# of Atoms 360Lattice

parameters11.483,11.483,24.

59

# of Unit cells 10

Boron Pink

Nitrogen Blue

Hydrogen White

3.9% hydrogen

Estevez et al. International Journal of Chemical, Materials Science and Engineering Vol:8 No:1, 2014

Presenter

Presentation Notes

HBNNT with the lattice size of 11.48 which was working for BNNT. Need to increase the box size.

HBNNT with Hydrogen externally bonded

HBNNT with Hydrogen externally bonded on Boron and internally bonded on Nitrogen

Estevez et al. International Journal of Chemical, Materials Science and Engineering Vol:8 No:1, 2014

Presenter

Presentation Notes

Two configuration that we used

(6,6) BNNT with Hydrogen

Run # 1 2 3 4

Diameter of BNNT

(Å)8.14 8.14 8.14 8.14

Lattice size (A=B,

C)12.3, 24.595 13.5,24.595

14.8,

24.59516.2, 24.595

Density (g/cm3) 1.383 1.148 0.955 0.797

(8,8) BNNT with Hydrogen

Run # 1 2 3 4

Diameter of BNNT

(Å)10.85 10.85 10.85 10.85

Lattice size (A=B,

C)15.5, 24.595 17.0,24.595

18.6,

24.59520.5, 24.595

Density (g/cm3) 1.525 1.329 1.190 1.103

Setting Simulation Parameters

Barostat Andersen

MDTemperature 298.0K

Thermostat Nose

FixCenterOfMass No

LangevinConstant 0.1

NoseRatio 1

NumSteps 50000

CellOptimizationScheme Fixed Basis Quality

Ensemble NVT

TimeStep 1.000 fs

•Density Functional Theory (DFT)

• Energy Minimization and Geometry Optimization: Becke, 3-Parameter, Lee-Yang-Parr (B3LYP)

•Elastic Constants: General Gradient Approximation (GGA) and the Perdew Wang (PW91) Functional Set.

Presenter

Presentation Notes

Energy Minimization and Geometry Optimization was performed by the hybridized Functional Becke, 3-Parameter, Lee-Yang-Parr Elastic Constants were calculated using the General Gradient Approximation (GGA) in Material Studio Elastic constants can not be calculated using the B3LYP **** Just in case not required to say for this slide just extra info***** Info on Hybrid Functional - Hybrid functionals are a class of approximations to the exchange-correlation energy functional in density functional theory (DFT) that incorporate a portion of exact exchange from Hartree-Fock theory with exchange and correlation from other sources (ab initio or empirical). The exact exchange energy functional is expressed in terms of the Kohn-Sham orbitals rather than the density, so is termed an implicit density functional

BNNTs Type 6,6 8,8

External Hydrogen Only

733 (%11.7)

715 (%10.1)

Hydrogen on External B and Internal N

732 (%11.8)

736 (%7.4)

No Hydrogen 830 795

Theoretical density of 2.28 g/cm3 and 2.62 g/cm3 were used for BNNT and HBNNT, respectively

Presenter

Presentation Notes

Interestingly, the changes of Young`s modulus for Hydrogen on the external side of B and the internal side of N for both (6,6) and (8,8) nanotubes is very close (11 and 10 percent, respectively) while for the external Hydrogen configuration, changes in E for (8,8) is smaller than (6,6) tubes. Even though further investigation is needed, addition of Hydrogen on only external sites has been demonstrated to have less effect on Young`s modulus of nanotubes with larger diameter. The relationship between tube diameter and the effect of introducing Hydrogen on Young`s modulus may be explained through atomic interactions between Hydrogen and B and N atoms. In the smaller tube, e.g.(6,6) with 0.814 nm diameter, the distances between atoms are so small that changing the position of Hydrogen from the outside to the inside of the tube might not affect the total interaction between the three types of atoms. On the other hand, the larger (8,8) Nanotubes (diameter of 1.085 nm) shows a dependence on the configuration of the hydrogen which is probably due to the increased distance between the atoms, resulting in a decreased disturbance on the overall system.

Nanostructures agglomeration

Epon 862/W + BNNT with Various Dispersion Techniques

7”x7”x(1/8”) Two Phase Composite

Tensile Strength of BNNT infused resin

(0.15%, 0.0825%, 0.015% BNNT)

Estevez et al. SAMPE 2014, Seattle

Thank You?

property prediction and fabrication of epon 862/w resin

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