Polymer/Inorganic NanocompositesPolymer/Inorganic NanocompositesOpportunities for Food Packaging BarrierOpportunities for Food Packaging Barrier

Evangelos ManiasDirector, Polymer Nanostructures LabMaterials Science & Engineering DeptPenn State University

manias@psu.edu

814-863-2980

http://zeus.plmsc.psu.edu

NanocompositesNanocomposites

A Definition1:

Polymer Nanocomposites The proper incorporation of nanoscale inorganic fillers to polymer matrices, so as to achieve novel (non-bulk) properties and multifunctionality(molecular hybrids or genuine nanocomposites 1 ).

Or (more common approach) design concurrent property improvements across a selected set of properties (nanofilled composites 1 ).

Today’s focus:

Polyolefin/Clay Nanocomposites Barrier (…and beyond)

1 E. Manias, Nature Materials 6, 9-11 (2007)

starting particle: agglomerate

• several μm in size (5-20 μm)

• millions of individual plateletsmorelikely

The Challenge: Achieving MiscibilityThe Challenge: Achieving Miscibility

desired

Courtesy: RA Vaia, AFRL, 2oo4

Thermodynamic ArgumentsThermodynamic Arguments

Designing miscible nanocomposites

introduce favorable excess interactionsi.e. polymer-clay interactions better than

clay-surfactant interactions

( )( ) ( )

fillerinorganic,surfactant,polymer:,

2with

2

jijiji

ABij

LWj

LWi

LWijAB

ijLWijij

−−++ −−=

−=+=

γγγγγ

γγγγγγ

Vaia & Giannelis, Macromolecules, 30, 7990 (1997)

0<− fillersurffillerpol γγ

Barrier properties of CompositesBarrier properties of Composites

0.0

0.2

0.4

0.6

0.8

1.0

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

Volume Fraction Silicate

Rel

ativ

e Pe

rmea

bilit

y

Nanocomposite(PCL Nanocomposites)

Conventionally filled systems

AB

Manias, Giannelis, et al. (1997)

‘Tortuous Path’

Macromolecules 2001, 34, 9189

effective α alignment

Permeability Permeability vs. vs. Path Path TortuousityTortuousity

Origins:path tortuosity

Similar Trends seenfor (Penn State work):(amorphous polymers)PDMS PU PUUPS Elastomers...(few semi-crystalline) PVA polyamides

Nanocomposites: Permeability Nanocomposites: Permeability vs. vs. StructureStructure

R. Xu, E. Manias, A.J. Snyder & J. Runt Macromolecules, 34, 337-339 (2001)

0

0.005

0.01

0.015

0.02

0.025

0.03

0 200 400 600 800 1000 1200 1400

Extension (%)

PUU

0.3%

0.8%

2%

3.8%

5.9%vol% silicate

Microtensile die (ASTM D1708-93)

HighHigh--Barrier Barrier PUUPUU Nanocomposites:Nanocomposites:elastomeric character retainedelastomeric character retained

R. Xu, E. Manias, A.J. Snyder & J. Runt Macromolecules, 34, 337-339 (2001)

Still Highly Rubbery !!Still Highly Rubbery !!

barrier incr. bybarrier incr. by 500%500%modulus incr. modulus incr. 500%500%strength incr.strength incr. 400%400%

Wilson high performance tennis ballsWilson high performance tennis balls

http://www.wilsonsports.com.au/tennis/doublecore.html

*InMat Inc. Air D-Fence Butyl-Rubber/Vermiculite nanocompositeWD Callister “Materials Science and

Engineering” 7th Ed. (Fig. 16.19)

Typical tactoid orientationTypical tactoid orientation

Orientated TactoidsOrientated Tactoids

Strategies to Orient Strategies to Orient nanofillersnanofillers

Sd = 0.8 @ mg systemsabove 20mg sample aligned

with 1500VAC for 10min @ AFRL

Sd = 0.6 @ kg/h systems

above made at 50–150 lb/h blow molding *

(2D nanoparticles)(2D nanoparticles)Electric-field AlignmentEpoxy/Epoxy/MMTMMT

Flow-induced AlignmentPE/PE/MMTMMT

* E. Manias, J. Zhang, MM Jimenez-Gasco, et al. Macrom. Rapid Comm., 30, 17-23 (2009)

What are effective aspectWhat are effective aspect--ratios?ratios?

0 200 400 600 800

0.0

0.2

0.4

0.6

0.8

1.0

R

elat

ive

Per

mea

bilit

y (P

com

p/Ppo

lym

)

filler aspect ratio (a)

φ=0.03 Nielsen modified Nielsen modified Cussler-Aris Fredrickson-Bicerano

0.00 0.05 0.10 0.15 0.200.0

0.2

0.4

0.6

0.8

1.0

R

elat

ive

Per

mea

bilit

y (P

com

p/Ppo

lym

)

volume fraction of filler (φ )

a=200 Nielsen modified Nielsen modified Cussler-Aris Fredrickson-Bicerano

How much filler does it take?How much filler does it take?

100μm

Poly(ethylene oxide)Poly(ethylene oxide) PolypropylenePolypropylene syndiosyndio‐‐PolystyrenePolystyrene

PEO/3 wt% PEO/3 wt% mmtmmt PP/3 wt% PP/3 wt% mmtmmt sPS/3 wt% sPS/3 wt% mmtmmt

Path Path TortuousityTortuousity around the fillers is around the fillers is notnot thethemost relevant quantity for crystalline polymersmost relevant quantity for crystalline polymers

More effective barrier structuresMore effective barrier structures

HouseHouse‐‐ofof‐‐Cards Structures                             Filler SequestratioCards Structures                             Filler Sequestration at Interfacesn at Interfaces

More effective barrier More effective barrier structuresstructures

HouseHouse‐‐ofof‐‐Cards Structures                             Filler SequestratioCards Structures                             Filler Sequestration at Interfacesn at Interfaces

200nm

M.Okamoto, P.H.Nam, P.Maiti, et al.Nano Letters, 1: 295 (2001)

Chung, Mason, Heidecker, ManiasPatent Pending, WO/2008/094167

In a first approach, controlled dispersion of wisely-selected nanoparticles can concurrently improve barrier with thermal and mechanical enhancements.

But, what about:-fine tuning a specific property (dialing in a value) ?-introducing a completely new functionality ?

moving on ...beyond barriermoving on ...beyond barrier

One approach, one can add other polymers:

LLDPE-graft-MAH / mmt LDPE-random-VA / mmt

Bridging !!

110 115 120 125 130 135 1400

2

4

6

8

10

12

14

16

0

10

20

30

Sealing Temperature ( °C )

Sea

l Stre

ngth

( N

/cm

)

PE/EVA on PE/EVA PE/EVA on PE/mmt PE/EVA on PE PE/mmt on PE/mmt PE on PE/mmt PE on PE

1000psi / 8sec

Frac

ture

Stre

ngth

( M

Pa

)

easy-openstrengths

HeatHeat--sealing: PEsealing: PE--based nanocompositesbased nanocomposites

E. Manias, et al. Macrom. Rapid Comm. 30: 17 (2009) & J Adhesion Sci & Techn 23: 709 (2009)

(nanocomposite PE-MAH / alkyl-MMT diluted by unfunctionalized PE)

LLDPE-graft-MAH

2Me-2alkyl-N+ MMT

seal interface

crack path(cohesive fracture)

EVA copolymer(grey regions)

mmt tactoids( )

Macromolecular Rapid Communications 30,17 (2009)Manias et al. J Adh Sci Techn 23,709 (2009)

nanocomposites w/ prescribed fracturenanocomposites w/ prescribed fracture

(nanocomposite PE-MAH / alkyl-MMT diluted by EVA & PE)

110 115 120 125 130 135 1400

2

4

6

8

10

12

14

16

0

5

10

15

20

25

30

Seal

Stre

ngth

( N

/cm

)

Sealing Temperature ( °C )

PE/EVA/mmt on PE/EVA/mmt PE/EVA/mmt on PE/EVA PE/EVA/mmt on PE/mmt PE/EVA/mmt on PE PE/EVA/mmt on HDPE

1000psi / 8sec

Frac

ture

Stre

ngth

( M

Pa )

LDPE-random-VA

2Me-2alkyl-N+ MMT

E. Manias, J. Zhang, et al., Macromolecular Rapid Comm. 30: 17 (2009)

nanocomposites w/ prescribed fracturenanocomposites w/ prescribed fracture

Strategy to introduce new functionalitiesStrategy to introduce new functionalities

Our best performing polyolefinnanocomposites are basedon alkyl-ammonium surfactant-OLSand are not antimicrobial

How can we design a compositethat affords antimicrobial activity?

Employ surfactants on the fillers that:have antimicrobial activity

andstill promote dispersion and good materials properties !

0 1 2 3 4 5 6 7 8

0

1

2

3

4

5

6

7

8

9 Surfactant Reduction

None 0% DDOAB 0% BDDAC 100% PEDPA 100%

Dia

met

er (c

m)

Time (Day)

Cationic surfactant candidates for Cationic surfactant candidates for OLSOLS

DDOAB

BDDACPEDPA

“alkyl”-only

benzyl-containing ethylene-oxide based

Penicillium roqueforti

Antimicrobial activity maintained even for Antimicrobial activity maintained even for surfactants tethered surfactants tethered (immobilized)(immobilized) on LSon LS

0 1 2 3 4 5 6 7 8

0123456789

10 Control MMT-DDOAB MMT-BDDAC MMT-PEDPA

Dia

met

er (c

m)

Time (Day)

P. roqueforti

Antifungal PE nanocomposite filmsAntifungal PE nanocomposite films

Control 6%MMT-BDDAC6%MMT-DDOAB 9%MMT-BDDAC

Experiment #2: Prevents germination and (thus) growth away from film P.claviforme

Experiment #1: Prevents growth on film P.roqueforti

Fungi Time

Spore Germination (%) PE

(control)

PE+6%MMT-

DDOAB

PE+6%MMT-

BDDAC

PE+9%MMT-

BDDAC

PE+6%MMT-

PEDPA

PE+9%MMT-

PEDPA

F.graminearum 10h 46 32 18 21 24 24

P.claviforme 48h 5 3 0 0 2 0

P.roqueforti 48h 7 6 0 0 3 2

Experiment #2: Prevents germination and (thus) growth away from film

Control 6%MMT-BDDAC6%MMT-DDOAB 9%MMT-BDDAC

Antifungal PE nanocomposite filmsAntifungal PE nanocomposite films

SummarySummary

Polymer/organoclay nanocomposites offer: concurrent property improvements (barrier + +)control of nanostructures at ton quantities (using industry’s current processing methods)fine tuning of properties (e.g. prescribed value of fracture toughness, viz. peel strength)new functionalities (e.g. antimicrobial, FR)

Viable Technology: Multiple commercial products

However: They are not the solution to all materials properties problems or performance requirements !!

Grad. students:Grad. students:Ken StrawheckerZhiming WangVikram KuppaSung Woo WeeAlexei KisselevMatt HeideckerGreg HogsheadTheresa FoleyPonusa SongptiyaNgoh ManokruangRomesh PatelFelipe Salcedo Financial Support:Financial Support:NIST NSF PDA DoE ONR AFOSR

Air Products UTC/IFC BAYER MATSCCoca-Cola Asahi-Kasei Arrow-BioMedSumitomo Chem PPG Samsung Kraft

Fuel-Cells/Solar-Cells:Zijie Lu Hungoo ChoA. Karatrantos Y. ChangD. Lentz

Collaborators:Collaborators:

T.C. Chung (PSU)J. Runt (PSU)R. Krishnamoorti (UH)R. Vaia (AFRL)C. Wilkie (Marquette)M. Jimenez-Gasco (PSU)D. Macdonald (PSU)J. Genzer (NCSU) J. Floros (PSU)C. Randall (PSU)R. Hedden

Postdocs:Postdocs:Lixin Wu Yang JiangHiroyoshi NakajimaM. RackaitisS. ChowdhuryJin-Huh YoungGeorge PolizosJinguo ZhangK.S. AndrikopoulosLingbin LuGlenna Malcolm

AcknowledgementsAcknowledgements all cited papers (full-text) here:http://zeus.plmsc.psu.edu/

Manias groupManias group

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Thank YouThank You

PRESENTED BY

Evangelos ManiasDirector, Polymer Nanostructures LabMaterials Science & Engineering DeptPenn State Universitymanias@psu.edu

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