Authors: Shaobo Xie, Umar Khan, Peter May, Oana M. Istrate and Jonathan N. Coleman

Boron Nitride Nanosheets As New BarrierAdditive For Plastic Packaging

Institution: CRANN & School of Physics, Trinity College Dublin, Dublin 2, Ireland

NEW/NANO MATERIALS

Two-dimensional Nano-platelets as Barrier Additives for Polymer Materials

Current Barrier Additives for Plastic Packaging

Boron Nitride Nanosheets from Liquid-exfoliation

500 nm

500 nm 500 n

500 1000 1500 2000 2500 3000 35000

5

10

15

20

25

30

35

40

Cou

nt

Flake Aspect Ratio

<L/t> = 1304 nm

Material and Process

Gas barrier Properties of BN filled PET Conclusions

References:1) Hyunwoo Kim, et al., ‘Graphene/ Polyurethane Nanocomposites for Improved Gas Barrier

and Electrical Conductivity’, Chem. Mater., 22, 3441 (2010).2) Compton O. C., et al., ‘Crumpled Graphene Nanosheets as Highly Effective Barrier Property

Enhancers’, Adv. Mater., 22, 4759 (2010).3) Ghanbari A., et al., ‘A novel approach to control thermal degradation of PET/organoclay

nanocomposites and improve clay exfoliation’, Polymer, 54, 1361 (2013).

1

12

Comp

Polymer

K

LKt

Theoretically the permeability ratio of composites to polymer matrices is afunction of the aspect ratio (L/t) of the 2D nano-platelet and its volume fraction(Φ) in the composites. The improved barrier properties of nanocomposites aremainly due to a tortuous path around these nanosheets, forcing the gaspermeant to travel a longer path to diffuse through the film.

Nanoclays

Graphene

h-BN

Can be an effective barrier additive

Usually high volume fraction needed due to its low aspect ratio in plastics.

A promising alternative due to its impermeable tomost gases, but it absorb light. This limits itsapplication in plastic packaging wheretransparency required.

+ =

BN

500 nm500 nm

Polyethylene Terephthalate (PET) resin was used as polymer matrix.

An internal mixer and a platen press were used to mix BN with polymer and make thin films for oxygen permeation analyses.

0.000 0.005 0.010 0.015 0.020 0.0250.0

0.2

0.4

0.6

0.8

1.0

L/t=1300

L/t=130

PET/BN experimental values

PU/GO melt experimental values1)

PS/GO experimental values2)

PET/clay melt experimental values3)

Kc/K

p

Filler volume fraction

theoretical predictions

BN filled PET films have super gas barrier without losing flexibility and transparency.

Φ

Boron Nitride nanosheets with a mean aspect ratio around 1300 were produced byliquid-exfoliation.

Melt processing involving dispersing BN nanosheets directly within the polymer meltwas carried out in an internal mixer. This method is most applicable for industrialapplications. The resultant PET-BN films have outstanding gas barrier while keepinggood processability, flexibility and transparency.

We have demonstrated that the layered hexagonal boron nitride (h-BN), an analogue ofgraphene, can be used as a new barrier additive for plastic packaging.