Thora Maltais

Roll-to-Roll Manufacturing of Films and Laminates Based on Cellulose Nanomaterials

George Chiu Alexander Wei Jeff Youngblood (PI) Pablo Zavattieri

Mechanical Eng. Chemistry

Materials Eng. Civil Eng.

Sustainable Nanomanufacturing: Creating the Industries of the Future

Birck Nanotechnology Center Consortium: Printing SMART Films

Industrial partners: Purdue investigators:

Forest Products Laboratories

Thora Maltais

• Industrial uses of multilayer laminates - Packaging films (e.g. food packaging, trash bags) * need flexibility, strength, chemical resistance, toughness, barriers - Surface coatings (e.g. safety glass) * need high strength, high-impact resistance, optical transparency

• Cellulose nanocrystals - High strength, transparency and flexibility - Control fracture mechanism to increase toughness - Biorenewable source-- reduced carbon footprint

translucent CN film 5-layer CN‒polymer film cellulose nanocrystals (CNs)

CNF film

Polymer

Multilayer laminate

Why nano-cellulose laminates?

Jeff Youngblood

Thora Maltais

• Scalable chemistry (grams to kilograms), with minimal increase in carbon footprint

• Wood-derived CNs produced on pilot plant scale

Objective 1: Solventless production of CN‒polymer nanocomposites

OO

HOHO

O O

OHHO

OH

OH

O O

OHHO

O

OO

O

catalytic DMSO(ball milling)

CO2-

O

CN (surface alcohols)

R

R

NH

NH

OTMSTMS

(ball milling)

O O

TMSOTMSO

OTMS

Cellulose nanocrystals (CNs) Environmentally

controlled pulverizer

Targeted polymer blends: ABS, polystyrene, rac-lactide (PLA)

CN−polymer blends: Surface-initiated polymerizations for increased miscibility

O O

OHHO

O

ON O

solventless SIP

CN-SANstyrene,

acrylonitrile O O

OHHO

O

ON O

CN Ph

n

Thora Maltais (Wei)

Thora Maltais

Objective 2: Roll-to-roll (R2R) production of CN-based films

Microgravure (Mirwec) for R2R lamination

Parameters for optimization: • Matching surface tension of

coating solution with substrate • R2R speed rate on coaxial

orientation of CNs • Reduction of nanoscale

defects on moving web • Reduction of residual stress

between substrate and film

Optical birefringence of CN films (0.5‒15 µm)

Reaz Chowdhury (Youngblood)

Characterization of uniaxial CN alignment by polarized optical microscopy

Uniaxial alignment

Thora Maltais

Objective 3: In-line detection of defects during R2R manufacturing

Wei-Tai Chen (Chiu)

Problem: • Fast-moving R2R process: difficult to

maintain even illuminance • Uneven illuminance make defects harder

to detect Solution: Algorithm for defect detection • Applicable toward morphology-

dependent scattering • Defects such as voids, scratches,

wrinkles and amorphous (gel) regions can be detected automatically.

CNC laminate on PET film using R2R process (15 μm thickness); images were captured off-line. void scratch gel wrinkle

Result of detection algorithm: Defects can be distinguished, even with uneven illuminance

blue rectangles: defects without dark contrast enhancement red rectangles: defects with contrast enhancement