Expanding the Processability and

Applications of Cellulose and Chitin

Nanomaterials

Carson Meredith

School of Chemical & Biomolecular

Engineering

Renewable Bioproducts Institute

Solid

Particles in composites, adhesives and films

Solid

Cellulose Nanofillers for

Polymers and CoatingsChitin-based Barrier

Materials

Engineering of Particles and Particle Interfaces

Nanomaterials from Cellulose

4

Acid Digestion

Cellulose

Nanocrystals (CNCs)

J. Mater. Chem., 2012, 22, 20105; Wood Handbook, 2010

Nanomaterials from Chitin

Nanomaterials from Chitin

Chitin Nanofibers Chitin Nanocrystals

1 µm

Acid Hydrolysis

Zeng et al. (2012)

Stiffness & Density Comparison

CNC on Par w/ Kevlar

MP

a

g/cm3

Objectives

Develop approaches to increase processability and utilization

of pilot/industrial-scale cellulose nanocrystals (CNCs) or chitin

nanofibers (ChNFs)

1) CNCs in polyurethane and acrylics

2) Spray coating of CNCs

USDA Forest Products Laboratory

CNC Pilot Production Facility

3) Process monitoring for optimization

of ChNF production

4) Spray-coated ChNF barrier

materials

ChNF Lab Production Facility

Georgia Tech

Chemical Modification of CNC Surface

Di-isocyanate Modification

+

IPDI Modified Cellulose (m-CNC)Cellulose (um-CNC)

60 °C

Catalyst

2 NCO: dibutyltin dilaurate (DBTDL)

2

1

Onset of degradation

increases by 20 °C for 5 wt.%

m-CNC composite

200

210

220

230

240

250

260

270

280

290

300

Onse

t o

f d

eg

rad

atio

n (C

)

0%

1% um-CNC

5% um-CNC

1% m-CNC

5% m-CNC

ACS Applied Materials & Interfaces, 2016

Mechanical Properties of poly(urethane)

nanocomposites

1 wt.% m-CNC 5 wt.% m-CNC

1 wt.% um-CNC 5 wt.% um-CNC

0 wt.% CNC

200 um

0

0.2

0.4

0.6

0.8

1

1.2

1.4

To

ug

hne

ss [J

/cm

3̂]

0%

1% um-CNC

1% m-CNC

5% um-CNC

5% m-CNC

257 %

0

2

4

6

8

10

12

14

16

Te

nsile

Str

eng

th [M

pa]

0%

1% um-CNC

1% m-CNC

5% um-CNC

5% m-CNC

226 %

5 wt.% m-CNC0 wt.% CNC 5 wt.% um-CNC

NCO chemistry as route to other

polymers

+ =

IEM

2-isocyanatoethylmethacrylate

CNC IEM/CNC

In-situ polymerization

+ =

MMA IEM/CNC IEM/CNC_PMMA

13

CNC Dispersion in Acrylic Polymers

IEM/CNC_PMMA

2.0 wt.%

CNC_PMMA

2.0 wt.%

Spray coating CNC-filled epoxy

Spray coating chitin

He

ate

d S

urf

ace

Ba

se

Po

lym

er

Nitrogen

Supply

Ch

itin

Su

sp

en

sio

nSu

bstr

ate

Water-

borne

CNC-

Epoxy

Prior work on CNC-waterborne

epoxy formulations

Xu,Girouard,Schueneman,Shofner Meredith Polymer 2013

Girouard,Xu,Schueneman,Shofner Meredith Polymer 2015

Neat 15% CNC

100 um

Spray coated epoxy – CNC composites

pH tracking

Reactors11 Nos.

Blocked

end

High Pressure

Orifice0.005”(Z5), 0.008”(Z8)

Cavitation & Shear Shear & Collisions

Lowered Pressure

Outlet

22 LPH (max)30,000 psi (max)

ChNF Production via Homogenization

ChNF Production via Homogenization

NH

HC=ONH2

Monitoring of surface area during processing via pH

+n m

++

+ +

++

+

+

+ +

+

++

+ +

+ ++ +

pH

Cycles

Low (8,600 psi), Mixed (15,000 & 22,000 psi) & High (25,000 psi)

0.5 wt. % pure chitin suspension in acetic acid (pH 3)

pH tracking

Use of pH to monitor chitin defibrillation

5 cycles 15 cycles

20 cycles 30 cycles

ChNF Morphology during processing

Spray coating chitin nanofibers

Spray coating chitin

He

ate

d S

urf

ace

Ba

se

Po

lym

er

Nitrogen

Supply

Ch

itin

Su

sp

en

sio

n

Barrier properties of chitin coated-PLA

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0.045

0.00 0.10 0.20

Oxygen

Tra

nsm

issi

on B

arri

er @

50

% R

H (

bar

rer)

Loading (g-coat/g-PLA)

Water vapor transmission

0

20

40

60

80

100

120

140

160

180

200

0 10 20 30 40 50 60 70 80 90 100

Wat

er V

apor

Tra

nsm

issi

on R

ate

(g-W

ater

/m2/d

ay)

Relative Humidity (%)

Coated Film 0.21 g-coat/g-

PLA loading

Control Film

Conclusions

CNCs

• Modification of CNC with IPDI was successful with improved

dispersion, thermal, and mechanical property compared to the

neat polyurethane

• NCO a practical route to other functional groups and polymers

• Spray-coating up to 15 wt% CNC in waterborne formulations

ChNFs

• pH a simple and useful measure of defibrillation

• Spray coating of ChNF aqueous dispersions

• Upgrading barrier properties of base films

Acknowledgements

Coauthors:

• Dr. Meisha Shofner, Georgia Tech MSE Faculty

• Dr. Greg Schueneman, USDA Forest Products Laboratory

• Dr. Shanhong Xu, GW University (former postdoc)

• Dr. Natalie Girouard, PolyOne (former PhD student)

Funding:

• USDA Forest Products Lab

• Georgia Tech Renewable Bioproducts Institute

PSE Fellowships & Equipment Grants