starch and packaging berthier soraruff fournier

Starch nanocrystals,
Innovation for packaging
Summary
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Introduction
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Different polymers for packaging
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Starch
–
Starch polymerization
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Hydrolysis and starch nanocrystals
–
Starch nanocrystals
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Incorporation into matrices
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Improvement with addition of starch nanocrystals
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Conclusion
Introduction
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Innovation for packaging from
renewable ressources
Nanotechnology and barrier
properties
High demand for flexible
packaging
Biodegradability and reduction of
dependy on petroleum resources
Different polymers for packaging
PLA (PolyLactic Acid)
nC3H6O3 → [C3H4O2]n + nH2O
acid → polyester
Lactic Acid
PLA
Lactid
PLA
Different polymers for packaging
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PHB: polyhydroxyl buteric acid
–
a polyester produced by
micro-organism ( as a
form of energy storage)
–
Sold under the name
Biopol
Ecoflex:
–
copolyester based on
petrochimical raw
materials
–
produced by BASF
poly(butylene adipateco-terephtalate)
Different polymers for packaging
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Ecovio:
–
–
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a bend of different
polymers:
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Ecoflex (55%)
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PLA (45%)
A polyester produced by
BASF
LDPE (low density polyethylene) :
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Thermoplastic
–
Free radical
polimerization
Starch
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Second most abondant biomass
material in nature
Natural, renewable,
biodegradable polymer
Formula : -(C6H10O5)nNo single structure, but a
predominant one :
semi-crystalline multiscale
structure
●
Composition : Amylose and
Amylopectin (glucosidic
polymers)
Starch polymerization
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Amylose
+ Amylopectin
+
+
+
enzyme →
??
Starch
→
●
Example of the amylose polymerization :
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(ATP + α-D-glucose 1-phosphate → diphosphate + ADP-glucose
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ADP-glucose + (1,4-α-D-glucosyl)n → ADP + (1,4-α-D-glucosyl)n+1)
Hydrolysis and Starch
nanocrystals
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Few works on it
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Particles of a few tens of nanometers in diameter
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Two step during the hydrolysis :
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a rapid one
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A second slower step
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Reaction of elimination
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Process :
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Starch granules (14.69wt%/acid) + 3.16 M of H2SO4 at 40°C
and 100 rpm
–
After 5 days, then centrifugations with distilled water and
treatment with homogenizer (2min, 13000 rpm) →
« stable » supension
Starch nanocrystals
Incorporation into matrices
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Hydroxyl groups → hydrophilic surface → aqueous solutions
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Surface treatment → wide range of organic solvents
–
Alkenyl succinic anhydrid (ASA) (70°C)
–
Phenylisocyanate (PI) (70°C)
–
Incorporation
Improvement with addition of
starch nanocrystals
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Mechanical Properties:
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An hight reinforcing effect according to the filler content ( weight
percent).
–
Improving the resistance to traction:
● Young's modulus
● Strength
● Strain and Break
╚►new type of network allowed by hydrogen bondings
Improvement with addition of starch
nanocrystals
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Physical Properties:
–
creation of a percolation filler network
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increase or decrease of water uptake
═►changing behavior of material ╗
╠═► according to filler content (wt %)
═►affect mechanical properties ╝
–
natural rubber matrix displayed the lowest water uptake (WU)
after 20 wt% creation of geometrical percolation effect
═►creation of diffusion pathway
Improvement with addition of
starch nanocrystals
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Barrier Properties:
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starch nanocrystals morphology: platelet
═► creation of tortuous pathway
–
many hydroxyl groups
═► hydrophilic nature of starch nanocrystals
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Water vapor permeability: WVP
–
O2 permeability
Conclusion :
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Promising fillers
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Advantages :
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Cost
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Purity
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Mechanical and barrier properties
Negative points :
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Reinforcing capabilty
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Duration of the hydrolysis process
However, research continues to improve
these caracteristics