Learning with Purpose Learning with Purpose

Biobased, Biodegradable Polymers and Coatings for Food Packaging

Prof. Ramaswamy (Ram) Nagarajan University of Massachusetts Lowell

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Plastics  demand  by  market  segment  

Source: Plastics Europe

Learning with Purpose Source: Plastics Europe

Plastic  consumption  by  type  

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Plastics  Packaging  Waste  –  the  dark  side  of  a  gift?  

Land  and  water  equally  Polluted  

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Mo1va1on  

1  Global  Industry  Analyst,    2  MSW  Genera6on,  Recycling,  and  Disposal  in  the  United  States  report,  2010  

!   By 2017 – Global plastics film and sheet production will exceed 100 Billion Pounds1

!   Currently more than 10 billion pounds of plastic packaging waste generated annually in the US alone2.

!   ~ 8 -10% of waste is recycled in US2

!   Recycling is only a partial solution •  Low density of plastics used in food packaging renders

recovery and recycling not economical •  Disposal infrastructure ?!

Motivation  

Packing waste - global problem

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Post  consumer  plastics  waste  recovery  efforts  are  improving    

But only in some countries - EU, Japan!

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How  about  Biodegradable  Plastics  for  food  packaging?  

Biobased Alternatives

PLA •  Nature Works Cargill •  Mitsui Chemicals •  Total/Galactic •  Teijin, Purac •  Zhejiang Hisun

PHA/PHB •  Metabolix/ADM (USA) •  Tianan (China) •  Copersucar (Brazil) •  Biomer (Germany)

Starch Based •  Novamont •  Rodenburg •  Biopolymers •  Végémat •  Limagrain •  Biotech •  Plantic Tech

Others • PCL • PBAT • Cellulosic based

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!   Resin availability

!   Inferior properties as compared to polyolefins

!   Processing issues - shear sensitivity and low thermal stability

!   High Oxygen Transmission Rate (OTR)

!   High Water Vapor Transmission Rate (WVTR)

!   Higher cost

!   Commercial composting is often required

Challenges  with  the  Current  Alternatives  

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Materials WVTR (g/m2*day*atm)

OTR (cc/m2*day*atm)

PLA (Nature works , 4032D) 375 >1000 PHB 178 350 PBAT (Ecoflex) 135 1200 PE-LD 425 1.-1.5 PP 150 0.5 EVOH 0.05-0.2 1-5 PET 5-10 2-4 PVDC 0.15 0.1

Material  Properties  Oxygen and Water Vapor Transmission Rates

!   Even for packaging dry foods like Coffee beans, bioplastics don’t meet the requirements •  WVTR < 8 g/m2*day*atm •  OTR < 55 cc/m2*day*atm

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!   Extend the functionality of the existing

biodegradable resins

!   Improve Oxygen Transmission Resistance and

Water Vapor Transmission Resistance

!   Use biodegradable and naturally occurring

materials

!   Achieve economic viability

Can  Bioplastics  be  tailored  for  food  packaging?  

Goals

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Layer  by  Layer  Coating  

Moisture  Barrier  

PLA  Film    

O2  Barrier  

Corona  Treated    PLA  Film  

-­‐   -­‐  -­‐  -­‐  -­‐  

 -­‐   -­‐  -­‐  -­‐  -­‐      

Oxygen  Barrier  Layer  

+  +  +  +    +  +  +  +  +  +  +  +  

pH  3-­‐5  

Dip  Coa6ng  

Moisture  Barrier  Layer  

Hot  Melt  Coa6ng  

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Oxygen Permeation Analyzer 8001 Water Vapor Transmission

ASTM D-3985 ASTM E- 96 / ASTM F-1249*

*  Tested  by  MOCON  

Characterization  of  OTR  and  WVTR  

12  

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Effect  of  pH  on  OTR  and  thickness  

0

0.1

0.2

0.3

0.4

0

20

40

60

80

pH  3   pH  4   pH  5  

Thickn

ess  (microns)  

OTR

,  cc/(m

2  x  da

y  x  atm)    

pH  of  Solu1on  

OTR   Thickness  

! As pH increased, Thicker layers are formed, decreasing OTR

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Effect  of  Coating  on  OTR  

1041.67

14.36 0

400

800

1200 O

TR, c

c/(m

2 ×

day ×

atm

) Neat PLA

Coated PLA

! Untreated PLA has a very poor barrier to Oxygen and thus the

OTR is relatively High at >1000 cc/(m2.day.atm)

! Biodegradable coating effectively reduces Oxygen transmission

from 1040 cc/(m2.day.atm) to <15 cc/(m2.day.atm)

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Mechanical  Properties  remain  intact  

0.074   0.074  

0  

0.02  

0.04  

0.06  

0.08  

Tensile  Strain  

Tensile  Strain  at  Yield  

Uncoated   Coated  Coated  Uncoated    

77.55   75.84  

0  

20  

40  

60  

80  

Tensile  Stren

gth  (M

Pa)  

Tensile  Strength  at  yield  

No  significant  change  in  mechanical  proper6es  aVer  coa6ng  

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Effect  of  Crosslinking  on  WVTR  

0.4938  

0.3704  

0.74  

0.3704  

0  

0.2  

0.4  

0.6  

0.8  

WVT

R  g/(m

2  x  day  x  atm

)  

Uncrosslinked  

MVTR  of  PLA  coated  with  Barrier  Layers  

Before  Abrasion     AXer  Abrasion    

Crosslinked  

Crosslinking    retains  barrier  proper6es  of  PLA  coated  films  

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!   A strategy for biobased, biodegradable polymer film with improved barrier properties has been developed and tested

!   OTR <10 cc/(m2 x day x atm) & WVTR <1.02 g/(m2 x day x atm) achievable

!   Crosslinking improves barrier properties and abrasion resistance of the coatings

!   Approach is scalable – engineering solution exists

Conclusions  

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!   Compostable bioplastics have a place in food packaging •  where low barrier properties can be tolerated •  thin films where recovery is not economical •  single use products

!   Recycling (down-cycling) should be part of the solution

!   Integration with disposal infrastructure –

requirement for making the entire exercise sensible

Outlook  for  food  packaging  Hilms  

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Acknowledgements  

Vishal  Bavishi   Zarif  Farhana  Mohd  Aris  

Thank  you!