PLA/AcrylPEG/L101 blend morphology Reactive extrusion of poly(lactide) with low molecular weight...
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PLA/AcrylPEG/L101 blend morphology Reactive extrusion of poly(lactide) with low molecular weight acryl- functionalized poly(ethylene glycol). An original and effective methodology to toughen poly(lactide) Georgio Kfoury 1, 2 , Fatima Hassouna 1 , Valérie Toniazzo 1 , Jean-Marie Raquez 2 , David Ruch 1 , Philippe Dubois 2 1 Department of Advanced Materials and Structures (DAMS), Centre de Recherche Public Henri Tudor, rue Bommel 5 (ZAE Robert Steichen), 4940 Hautcharage, LUXEMBOURG 2 UMons Research Institut for Materials Science and Engineering, Laboratory of Polymeric and Composite Materials, University of Mons (UMONS), Place du Parc 23, 7000 Mons, BELGIUM State of the art Poly(lactide) (PLA) is one of the most extensively studied biodegradable thermoplastics derived from renewable resources. One of the main drawbacks of PLA is its inherent brittleness, which limits its applications. Plasticization of PLA with low molecular weight poly(ethylene glycol) (PEG) is currently carried out to sustain this issue, but it results the migration of plasticizer at high PEG loadings. Conclusions High grafting extent of AcrylPEG: Formation of a low AcrylPEG oligomers (DP~7) fraction (extracted by Soxhlet) and a highly grafted fraction of poly(AcrylPEG) in PLA (not extracted by Soxhlet) Limited plasticizer migration after DMA It comes out a much limited migration of the plasticizer, which needs to be quantified by further physical aging. Efficient plasticization/ductility and improved impact resistance with increasing L101 In situ generation of particular rubbery micro- and nano-domains : soft poly(acrylPEG)-rich cores having an “immiscibility gradient” Acknowledgments Thanks to the AMS Department of CRP Henri Tudor and the Laboratory of Polymeric and Composite Materials (LPMC) for the technical and scientific supports and the Fond National de la Recherche (FNR) for the financial support. Molecular characterization Original approach In situ polymerization and free-radical grafting of acryl- functionalized PEG onto PLA backbone via reactive extrusion aims to reduce the migration of the plasticizer. PLA PLA/AcrylPEG/ L101 PLA/ AcrylPEG Mechanical properties Material/Blend (compositions in wt. %) Extracted ftaction by Soxhlet (%) T g (°C) DMA Storage Modulus E’ at 20°C (MPa) Impact energy a (kJ/m 2 ) Elongatio n at break b (%) PLA PLA/L101 (99.5/0.5) 60 1800 3 4 - 5 PLA/AcrylPEG (80/20) PLA/AcrylPEG/ L101 (79.5/20/0.5) 18 8 35 40 800 1000 80 110 (No break) 250 200 Reactive extrusion (REx) Drying PLA under vacuum at 60°C over night Dry PLA Dry material AcrylPEG + L101 Compression moulding on a Carver manual press : Moulding Temperature = 180°C; Moulding time = 10 min REx under N 2 co- rotating twin-screw extruder DSM Xplore (15cc): T melt ~ 175°C; scew speed = 100 rpm; REx time = 5 min 0 1 2 3 4 5 0 2000 4000 6000 PLA /A crylPE G (80/20 in w t% ) PLA /A crylPE G /L 101 (79.75/20/0.25 in w t% ) PLA /A crylPE G /L 101 (79.5/20/0.5 in w t% ) E xtrusion force (N ) Tim e (m in) PolyAcrylPEG grafted on PLA AcrylPEG OligoAcrylPEG (DP~7) Efficient plasticization resulting in improved ductility and impact resistance with increasing L101 amount In the absence of L101, AcrylPEG migrated to the surface of the specimen after DMA, while it was not the case in the presence of L101 Soft domains (after cryofracture) made of poly(acrylPEG) (core) surrounded with an immiscibility gradient are observed due to the grafting of acrylPEG on PLA (shell) Core-shell microdomains played a stress concentrator role and impact energy dissipation fracture inhibitors 6 8 10 12 14 16 18 Solid m aterialafter Soxhlet E xtraction R ID response R etention tim e (m in) PLA /A crylPE G (80/20 w t.% ) PLA /A crylPE G /L 101 (79.75/20/0.25 w t.% ) PLA /A crylPE G /L 101 (79.5/20/0.5 w t.% ) N eatA crylPE G 6 8 10 12 14 16 18 Solid m aterialbefore Soxhlet E xtraction R ID response R etention tim e (m in) PLA /A crylPE G (80/20 w t.%) PLA /A crylPE G /L 101 (79.75/20/0.25 w t.% ) PLA /A crylPE G /L 101 (79.5/20/0.5 w t.%) N eatA crylPE G 6 8 10 12 14 16 18 L iquid extracted fraction by Soxhlet R ID response R etention tim e (m in) PLA /A crylPE G (80/20 w t.% ) PLA /A crylPE G /L 101 (79.75/20/0.25 w t.% ) PLA /A crylPE G /L 101 (79.5/20/0.5 w t.% ) N eatA crylPE G + H O C OH O CH 3 CH 3 O H O O H 2 C m AcrylPEG n PLA* 180°C Grafted poly(acrylPEG) o PLA backbone + CH 3 O OH H O H H O C OH O CH 3 R OH O R 180°C PLA n n PLA* R O H 2 C O O H O CH 3 O CH 3 O O H CH 3 O O O CH O O CH 3 O R O 9 9 9 175°C Linear propagatio 9 Formation of a low AcrylPEG oligomers (DP~7) fraction (extracted by Soxhlet) Formation of a highly grafted fraction of poly(AcrylPEG) in PLA (not extracted by Soxhlet in methanol) Lupersol101 (L101) CH 3 CH 3 H 3 C CH 3 CH 3 CH 3 H 3 C CH 3 CH 3 O O O O H 3 C 715 nm 440 nm H 2 C O O O CH 3 H CH 3 O OH O H CH 3 O O O H O OH O CH 3 R O R OH R O O R CH 3 O O O m AcrylPEG n PLA Grafted poly(acrylPEG) o PLA backbone n m (L101) + + p m
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Transcript of PLA/AcrylPEG/L101 blend morphology Reactive extrusion of poly(lactide) with low molecular weight...
PLA/AcrylPEG/L101 blend morphology
Reactive extrusion of poly(lactide) with low molecular weight acryl-functionalized poly(ethylene glycol).An original and effective methodology to toughen poly(lactide)
Georgio Kfoury1, 2, Fatima Hassouna1, Valérie Toniazzo1, Jean-Marie Raquez2, David Ruch1, Philippe Dubois2
1Department of Advanced Materials and Structures (DAMS), Centre de Recherche Public Henri Tudor, rue Bommel 5 (ZAE Robert Steichen), 4940 Hautcharage, LUXEMBOURG2UMons Research Institut for Materials Science and Engineering, Laboratory of Polymeric and Composite Materials, University of Mons (UMONS), Place du Parc 23, 7000 Mons,
BELGIUM
State of the art
Poly(lactide) (PLA) is one of the most extensively studied biodegradable
thermoplastics derived from renewable resources. One of the main
drawbacks of PLA is its inherent brittleness, which limits its applications.
Plasticization of PLA with low molecular weight poly(ethylene glycol)
(PEG) is currently carried out to sustain this issue, but it results the
migration of plasticizer at high PEG loadings.
Conclusions
High grafting extent of AcrylPEG:
Formation of a low AcrylPEG oligomers (DP~7) fraction (extracted by Soxhlet) and a highly
grafted fraction of poly(AcrylPEG) in PLA (not extracted by Soxhlet)
Limited plasticizer migration after DMA
It comes out a much limited migration of the plasticizer, which needs to be quantified by further
physical aging.
Efficient plasticization/ductility and improved impact resistance with increasing L101
In situ generation of particular rubbery micro- and nano-domains : soft poly(acrylPEG)-rich cores
having an “immiscibility gradient” with surrounding PLA due to the grafting reaction.
Acknowledgments
Thanks to the AMS Department of CRP
Henri Tudor and the Laboratory of
Polymeric and Composite Materials (LPMC)
for the technical and scientific supports and
the Fond National de la Recherche (FNR) for
the financial support.
Molecular characterization
Original approachIn situ polymerization and free-radical grafting of acryl-functionalized PEG onto PLA backbone via reactive extrusion aims to reduce the migration of the plasticizer.
PLAPLA/AcrylPEG/L101
PLA/AcrylPEG
Mechanical propertiesMaterial/Blend
(compositions in wt. %)Extracted ftaction
by Soxhlet (%)Tg
(°C)DMA
Storage Modulus E’ at 20°C (MPa)
Impact energya (kJ/m2)
Elongation at breakb (%)
PLA
PLA/L101 (99.5/0.5)60 1800 3 4 - 5
PLA/AcrylPEG (80/20)
PLA/AcrylPEG/L101 (79.5/20/0.5)
18
8
35
40
800
1000
80
110(No break)
250
200
Reactive extrusion (REx)
Drying PLA under vacuum at 60°C over night
Dry PLA Dry material
AcrylPEG + L101
Compression moulding on a Carver manual press :
Moulding Temperature = 180°C; Moulding time = 10 min
REx under N2 co-rotating twin-screw extruder DSM Xplore (15cc):
Tmelt ~ 175°C; scew speed = 100 rpm; REx time = 5 min
0 1 2 3 4 50
2000
4000
6000
PLA/AcrylPEG (80/20 in wt %) PLA/AcrylPEG/L101 (79.75/20/0.25 in wt %) PLA/AcrylPEG/L101 (79.5/20/0.5 in wt %)E
xtru
sion
for
ce (
N)
Time (min)
PolyAcrylPEG
grafted on PLA
AcrylPEG
OligoAcrylPEG
(DP~7)
Efficient plasticization resulting in improved ductility and impact resistance with increasing L101 amount
In the absence of L101, AcrylPEG migrated to the surface of the specimen after DMA, while it was not the case in the presence of L101
Soft domains (after cryofracture) made of poly(acrylPEG) (core) surrounded with an immiscibility gradient are observed due to the grafting of acrylPEG on PLA (shell)
Core-shell microdomains played a stress concentrator role and impact energy dissipation fracture inhibitors
6 8 10 12 14 16 18
Solid material after Soxhlet Extraction
RID
res
pons
e
Retention time (min)
PLA/AcrylPEG (80/20 wt. %) PLA/AcrylPEG/L101 (79.75/20/0.25 wt. %) PLA/AcrylPEG/L101 (79.5/20/0.5 wt. %)
Neat AcrylPEG
6 8 10 12 14 16 18
Solid material beforeSoxhlet Extraction
RID
res
pons
e
Retention time (min)
PLA/AcrylPEG (80/20 wt. %) PLA/AcrylPEG/L101 (79.75/20/0.25 wt. %) PLA/AcrylPEG/L101 (79.5/20/0.5 wt. %)
Neat AcrylPEG
6 8 10 12 14 16 18
Liquid extracted fraction by Soxhlet
RID
res
pons
e
Retention time (min)
PLA/AcrylPEG (80/20 wt. %) PLA/AcrylPEG/L101 (79.75/20/0.25 wt. %) PLA/AcrylPEG/L101 (79.5/20/0.5 wt. %)
Neat AcrylPEG
+H
OC OH
OCH3
CH3
O
H
OO
H2C
m
AcrylPEG
nPLA*
180°C Grafted poly(acrylPEG) on PLA backbone
+CH3
O
OH
H
OH H
OC OH
OCH3
R OH
OR
180°C
PLA
n n
PLA*
R O H2CO
O
H
O
CH3
O
CH3
O
OH
CH3O
O O
CH
O
OCH3
O
R O
9
9
9
175°C
Linear propagation
9
Formation of a low AcrylPEG oligomers (DP~7) fraction
(extracted by Soxhlet)
Formation of a highly grafted fraction of poly(AcrylPEG) in PLA
(not extracted by Soxhlet in methanol)
Lupersol101 (L101)
CH3CH3
H3CCH3
CH3
CH3
H3CCH3
CH3OO
OOH3C
715 nm440 nm
H2CO
O
O
CH3
H
CH3
O
OHO
H
CH3
O
O
O
HO
OH
OCH3
R O
R OH
R O O R
CH3
O
O
O
m
AcrylPEGn
PLA
Grafted poly(acrylPEG) on PLA backbone
n
m
(L101)
+ +
p
m
