Post on 15-Mar-2020
transcript
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
...
...
Thank YouThank You
PRESENTED BY
Evangelos ManiasDirector, Polymer Nanostructures LabMaterials Science & Engineering DeptPenn State Universitymanias@psu.edu
Please remember to turn in your evaluation sheet...