Blends containing 85 wt. % of an amorphous polylactide with 15 wt. % of three different semicrystalline PLA (cPLA) grades with different crystallizabilty were separately blended via a twin-screw extruder below the melting temperature of the cPLAs. The extrudates were either directly pelletized or pelletized after being drawn at a draw ratio of 10. The small amplitude oscillatory shear behavior of the samples revealed that while the rheological properties of the undrawn samples were enhanced, those of the drawn samples were much more dramatically increased. In undrawn samples, the enhancements were due to the presence of unmelted crystal clusters, which could form a solid network structure in the blend. The much more pronounced increases in drawn samples, however, were due to the transformation of the crystal clusters into the fiberlike oriented crystal network, which formed a stronger solid network. This reinforcing behavior in both undrawn and drawn samples was even more pronounced when cPLA with a higher degree of crystallinity and a higher melting temperature was used. In drawn samples, the stress growth experiments confirmed the formation of such oriented crystal structure during which the primary overshoot caused by the crystal network structure could be formed again after molecular relaxation. This was while, in undrawn samples, stress overshoots were barely visible.

1.
Sinclair
,
R. G.
, “
The case for polylactic acid as a commodity packaging plastic
,”
J. Macromol. Sci., Part A: Pure Appl.Chem.
33
,
585
597
(
1996
).
2.
Grijpma
,
D. W.
, and
A. J.
Pennings
, “
(Co)polymers of L-lactide, 2. Mechanical properties
,”
Macromol. Chem. Phys.
195
,
1649
1663
(
1994
).
3.
Auras
,
R.
,
B.
Harte
, and
S.
Selke
, “
An overview of polylactides as packaging materials
,”
Macromol. Biosci.
4
,
835
864
(
2004
).
4.
Garlotta
,
D.
, “
A literature review of poly(lactic acid)
,”
J. Polym. Environ.
9
,
63
84
(
2001
).
5.
Gupta
,
B.
,
N.
Revagade
, and
J.
Hilborn
, “
Poly(lactic acid) fiber: An overview
,”
Prog. Polym. Sci.
32
,
455
482
(
2007
).
6.
Lim
,
L.-T.
,
R.
Auras
, and
M.
Rubino
, “
Processing technologies for poly(lactic acid)
,”
Prog. Polym. Sci.
33
,
820
852
(
2008
).
7.
Nofar
,
M.
, and
C. B.
Park
,
Polylactide foams fundamentals, manufacturing, and applications
, in
Polylactide Foams Fundamentals, Manufacturing, and Applications
(
Elsevier
,
New York
,
2017
).
8.
Nofar
,
M.
, and
C. B.
Park
,
Poly (lactic acid) foaming
, in
Progress in Polymer Science
(
Elsevier Ltd
,
New York
,
2014
), Vol.
39
, pp.
1721
1741
.
9.
Nofar
,
M.
,
R.
Salehiyan
, and
S.
Sinha Ray
, “
Rheology of poly (lactic acid)-based systems
,”
Polym. Rev.
59
,
465
509
(
2019
).
10.
Rasal
,
R. M.
,
A. V.
Janorkar
, and
D. E.
Hirt
, “
Poly(lactic acid) modifications
,”
Prog. Polym. Sci.
35
,
338
356
(
2010
).
11.
Saeidlou
,
S.
,
M. A.
Huneault
,
H.
Li
, and
C. B.
Park
, “
Poly(lactic acid) crystallization
,”
Prog. Polym. Sci.
37
,
1657
1677
(
2012
).
12.
Drumright
,
R. E.
,
P. R.
Gruber
, and
D. E.
Henton
, “
Polylactic acid technology
,”
Adv. Mater.
12
,
1841
1846
(
2000
).
13.
Lunt
,
J.
, “
Large-scale production, properties and commercial applications of poly lactic acid polymers
,”
Polym. Degrad. Stab.
59
,
145
152
(
1998
).
14.
Jalali
,
A.
,
M. A.
Huneault
,
M.
Nofar
,
P. C.
Lee
, and
C. B.
Park
, “
Effect of branching on flow-induced crystallization of poly (lactic acid)
,”
Eur. Polym. J.
119
,
410
420
(
2019
).
15.
Nofar
,
M.
,
W.
Zhu
,
C. B.
Park
, and
J.
Randall
, “
Crystallization kinetics of linear and long-chain-branched polylactide
,”
Ind. Eng. Chem. Res.
50
,
13789
13798
(
2011
).
16.
Nofar
,
M.
,
W.
Zhu
, and
C. B.
Park
, “
Effect of dissolved CO2 on the crystallization behavior of linear and branched PLA
,”
Polymer (Guildf.)
53
,
3341
3353
(
2012
).
17.
Najafi
,
N.
,
M. C.
Heuzey
,
P. J.
Carreau
,
D.
Therriault
, and
C. B.
Park
, “
Mechanical and morphological properties of injection molded linear and branched-polylactide (PLA) nanocomposite foams
,”
Eur. Polym. J.
73
,
455
465
(
2015
).
18.
Najafi
,
N.
,
M. C.
Heuzey
,
P. J.
Carreau
,
D.
Therriault
, and
C. B.
Park
, “
Rheological and foaming behavior of linear and branched polylactides
,”
Rheol. Acta
53
,
779
790
(
2014
).
19.
Najafi
,
N.
,
M. C.
Heuzey
,
P.
Carreau
, and
D.
Therriault
, “
Quiescent and shear-induced crystallization of linear and branched polylactides
,”
Rheol. Acta
54
,
831
845
(
2015
).
20.
Mihai
,
M.
,
M. A.
Huneault
, and
B. D.
Favis
, “
Rheology and extrusion foaming of chain-branched poly(lactic acid)
,”
Polym. Eng. Sci.
50
,
629
642
(
2010
).
21.
Eslami
,
H.
, and
M. R.
Kamal
, “
Effect of a chain extender on the rheological and mechanical properties of biodegradable poly(lactic acid)/poly[(butylene succinate)-co-adipate] blends
,”
J. Appl. Polym. Sci.
129
,
2418
2428
(
2013
).
22.
Nofar
,
M.
, “
Synergistic effects of chain extender and nanoclay on the crystallization behaviour of polylactide
,”
Int. J. Mater. Sci. Res.
1
,
1
8
(
2018
).
23.
Raquez
,
J.-M.
,
Y.
Habibi
,
M.
Murariu
, and
P.
Dubois
, “
Polylactide (PLA)-based nanocomposites
,”
Prog. Polym. Sci.
38
,
1504
1542
(
2013
).
24.
Sinha Ray
,
S.
,
P.
Maiti
,
M.
Okamoto
,
K.
Yamada
, and
K.
Ueda
, “
New polylactide/layered silicate nanocomposites. 1. Preparation, characterization, and properties
,”
Macromolecules
35
,
3104
3110
(
2002
).
25.
Sinha Ray
,
S.
, and
M.
Okamoto
, “
Polymer/layered silicate nanocomposites: A review from preparation to processing
,”
Prog. Polym. Sci.
28
,
1539
1641
(
2003
).
26.
Vatansever
,
E.
,
D.
Arslan
, and
M.
Nofar
, “
Polylactide cellulose-based nanocomposites
,”
Int. J. Biol. Macromol.
137
,
912
938
(
2019
).
27.
Keshtkar
,
M.
,
M.
Nofar
,
C. B.
Park
, and
P. J.
Carreau
, “
Extruded PLA/clay nanocomposite foams blown with supercritical CO2
,”
Polymer (Guildf.)
55
,
4077
4090
(
2014
).
28.
Kamal
,
M. R.
, and
V.
Khoshkava
, “
Effect of cellulose nanocrystals (CNC) on rheological and mechanical properties and crystallization behavior of PLA/CNC nanocomposites
,”
Carbohydr. Polym.
123
,
105
114
(
2015
).
29.
Bagheriasl
,
D.
,
P. J.
Carreau
,
B.
Riedl
,
C.
Dubois
, and
W. Y.
Hamad
, “
Shear rheology of polylactide (PLA)–cellulose nanocrystal (CNC) nanocomposites
,”
Cellulose
23
,
1885
1897
(
2016
).
30.
Vatansever
,
E.
,
D.
Arslan
,
D. S.
Sarul
,
Y.
Kahraman
, and
M.
Nofar
, “
Effects of molecular weight and crystallizability of polylactide on the cellulose nanocrystal dispersion quality in their nanocomposites
,”
Int. J. Biol. Macromol.
154
,
276
290
(
2020
).
31.
Arslan
,
D.
,
E.
Vatansever
,
D. S.
Sarul
,
Y.
Kahraman
,
G.
Gunes
,
A.
Durmus
, and
M.
Nofar
, “
Effect of preparation method on the properties of polylactide/cellulose nanocrystal nanocomposites
,”
Polym. Compos.
41
(
10
),
4170
4180
(
2020
).
32.
Mohammadi
,
M.
,
C.
Bruel
,
M. C.
Heuzey
, and
P. J.
Carreau
, “
CNC dispersion in PLA and PBAT using two solvents: Morphological and rheological properties
,”
Cellulose
27
,
9877
9892
(
2020
).
33.
Nofar
,
M.
,
D.
Sacligil
,
P. J.
Carreau
,
M. R.
Kamal
, and
M.-C.
Heuzey
, “
Poly (lactic acid) blends: Processing, properties and applications
,”
Int. J. Biol. Macromol.
125
,
307
360
(
2018
).
34.
Joziasse
,
C. A. P.
,
M. D. C.
Topp
,
H.
Veenstra
,
D. W.
Grijpma
, and
A. J.
Pennings
, “
Supertough poly(lactide)s
,”
Polym. Bull.
33
,
599
605
(
1994
).
35.
Sarazin
,
P.
,
G.
Li
,
W. J.
Orts
, and
B. D.
Favis
, “
Binary and ternary blends of polylactide, polycaprolactone and thermoplastic starch
,”
Polymer (Guildf.)
49
,
599
609
(
2008
).
36.
Nofar
,
M.
,
R.
Salehiyan
,
U.
Ciftci
,
A.
Jalali
, and
A.
Durmuş
, “
Ductility improvements of PLA-based binary and ternary blends with controlled morphology using PBAT, PBSA, and nanoclay
,”
Compos., Part B
182
,
107661
(
2020
).
37.
Nofar
,
M.
,
A.
Tabatabaei
,
H.
Sojoudiasli
,
C. B.
Park
,
P. J.
Carreau
,
M. C.
Heuzey
, and
M. R.
Kamal
, “
Mechanical and bead foaming behavior of PLA-PBAT and PLA-PBSA blends with different morphologies
,”
Eur. Polym. J.
90
,
231
244
(
2017
).
38.
Nofar
,
M.
,
H.
Oguz
, and
D.
Ovalı
, “
Effects of the matrix crystallinity, dispersed phase, and processing type on the morphological, thermal, and mechanical properties of polylactide-based binary blends with poly[(butylene adipate)-co-terephthalate] and poly[(butylene succinate)-co-adipate]
,”
J. Appl. Polym. Sci.
136
,
47636
(
2019
).
39.
Nofar
,
M.
,
M.
Mohammadi
, and
P. J.
Carreau
, “
Effect of TPU hard segment content on the rheological and mechanical properties of PLA/TPU blends
,”
J. Appl. Polym. Sci.
137
,
49387
(
2020
).
40.
Ojijo
,
V.
, and
S. S.
Ray
, “
Super toughened biodegradable polylactide blends with non-linear copolymer interfacial architecture obtained via facile in-situ reactive compatibilization
,”
Polymer (Guildf.)
80
,
1
17
(
2015
).
41.
Zolali
,
A. M.
, and
B. D.
Favis
, “
Toughening of cocontinuous polylactide/polyethylene blends via an interfacially percolated intermediate phase
,”
Macromolecules
51
,
3572
3581
(
2018
).
42.
Zolali
,
A. M.
,
V.
Heshmati
, and
B. D.
Favis
, “
Ultratough co-continuous PLA/PA11 by interfacially percolated poly(ether-b-amide)
,”
Macromolecules
50
,
264
274
(
2017
).
43.
Nofar
,
M.
,
M.-C.
Heuzey
,
P. J.
Carreau
, and
M. R.
Kamal
, “
Nanoparticle interactions and molecular relaxation in PLA/PBAT/nanoclay blends
,”
Exp. Results
1
,
e47
(
2020
).
44.
Wang
,
L.
,
R. E.
Lee
,
G.
Wang
,
R. K. M.
Chu
,
J.
Zhao
, and
C. B.
Park
, “
Use of stereocomplex crystallites for fully-biobased microcellular low-density poly(lactic acid) foams for green packaging
,”
Chem. Eng. J.
327
,
1151
1162
(
2017
).
45.
Saeidlou
,
S.
,
M. A.
Huneault
,
H.
Li
, and
C. B.
Park
, “
Poly(lactic acid) stereocomplex formation: Application to PLA rheological property modification
,”
J. Appl. Polym. Sci.
131
,
40173
(
2014
).
46.
Saeidlou
,
S.
,
M. A.
Huneault
,
H.
Li
,
P.
Sammut
, and
C. B.
Park
, “
Evidence of a dual network/spherulitic crystalline morphology in PLA stereocomplexes
,”
Polymer (Guildf.)
53
,
5816
5824
(
2012
).
47.
Srithep
,
Y.
,
D.
Pholharn
,
L. S.
Turng
, and
O.
Veang-In
, “
Injection molding and characterization of polylactide stereocomplex
,”
Polym. Degrad. Stab.
120
,
290
299
(
2015
).
48.
Tsuji
,
H.
,
Poly(lactic acid) stereocomplexes: A decade of progress
, in
Advanced Drug Delivery Reviews
(
Elsevier B.V.
,
New York
,
2016
), Vol.
107
, pp.
97
135
.
49.
Gil-Castell
,
O.
,
J. D.
Badia
,
S.
Ingles-Mascaros
,
R.
Teruel-Juanes
,
A.
Serra
, and
A.
Ribes-Greus
, “
Polylactide-based self-reinforced composites biodegradation: Individual and combined influence of temperature, water and compost
,”
Polym. Degrad. Stab.
158
,
40
51
(
2018
).
50.
Jia
,
W.
,
R. H.
Gong
, and
P. J.
Hogg
, “
Poly (lactic acid) fibre reinforced biodegradable composites
,”
Compos., Part B
62
,
104
112
(
2014
).
51.
Li
,
R.
, and
D.
Yao
, “
Preparation of single poly(lactic acid) composites
,”
J. Appl. Polym. Sci.
107
,
2909
2916
(
2008
).
52.
Matabola
,
K. P.
,
A. R.
De Vries
,
F. S.
Moolman
, and
A. S.
Luyt
, “
Single polymer composites: A review
,”
J. Mater. Sci.
44
,
6213
6222
(
2009
).
53.
Gao
,
C.
,
L.
Yu
,
H.
Liu
, and
L.
Chen
, “
Development of self-reinforced polymer composites
,” in
Progress in Polymer Science
(
Pergamon
,
New York
,
2012
), pp.
767
780
.
54.
Somord
,
K.
,
O.
Suwantong
,
N.
Tawichai
,
T.
Peijs
, and
N.
Soykeabkaew
, “
Self-reinforced poly(lactic acid) nanocomposites of high toughness
,”
Polymer (Guildf.)
103
,
347
352
(
2016
).
55.
Gao
,
C.
,
L.
Meng
,
L.
Yu
,
G. P.
Simon
,
H.
Liu
,
L.
Chen
, and
S.
Petinakis
, “
Preparation and characterization of uniaxial poly(lactic acid)-based self-reinforced composites
,”
Compos. Sci. Technol.
117
,
392
397
(
2015
).
56.
Mai
,
F.
,
W.
Tu
,
E.
Bilotti
, and
T.
Peijs
, “
Preparation and properties of self-reinforced poly(lactic acid) composites based on oriented tapes
,”
Compos., Part A
76
,
145
153
(
2015
).
57.
Goutianos
,
S.
,
L.
Van der Schueren
, and
J.
Beauson
, “
Failure mechanisms in unidirectional self-reinforced biobased composites based on high stiffness PLA fibres
,”
Compos., Part A
117
,
169
179
(
2019
).
58.
Bocz
,
K.
,
M.
Domonkos
,
T.
Igricz
,
Á
Kmetty
,
T.
Bárány
, and
G.
Marosi
, “
Flame retarded self-reinforced poly(lactic acid) composites of outstanding impact resistance
,”
Compos., Part A
70
,
27
34
(
2015
).
59.
Zengwen
,
C.
,
H.
Pan
,
Y.
chen
,
J.
Bian
,
L.
Han
,
H.
Zhang
,
L.
Dong
, and
Y.
Yang
, “
Transform poly (lactic acid) packaging film from brittleness to toughness using traditional industrial equipments
,”
Polymer (Guildf.)
180
,
121728
(
2019
).
60.
Xie
,
L.
,
X.
Sun
,
Y.
Tian
,
F.
Dong
,
M.
He
,
Y.
Xiong
, and
Q.
Zheng
, “
Self-nanofibrillation strategy to an unusual combination of strength and toughness for poly(lactic acid)
,”
RSC Adv.
7
,
11373
11380
(
2017
).
61.
Jalali
,
A.
,
J. H.
Kim
,
A. M.
Zolali
,
I.
Soltani
,
M.
Nofar
,
E.
Behzadfar
, and
C. B.
Park
, “
Peculiar crystallization and viscoelastic properties of polylactide/polytetrafluoroethylene composites induced by in-situ formed 3D nanofiber network
,”
Compos., Part B
200
,
108361
(
2020
).
62.
Kelnar
,
I.
,
Ü
Bal
,
A.
Zhigunov
,
L.
Kaprálková
,
I.
Fortelný
,
S.
Krejčíková
, and
J.
Kredatusová
, “
Complex effect of graphite nanoplatelets on performance of HDPE/PA66 microfibrillar composites
,”
Compos., Part B
144
,
220
228
(
2018
).
63.
Kelnar
,
I.
,
Ü
Bal
,
A.
Zhigunov
,
L.
Kaprálková
,
I.
Fortelný
,
S.
Krejčíková
,
J.
Kredatusová
,
J.
Dybal
,
M.
Janata
, and
M.
Nofar
, “
Nano-modified HDPE/PA6 microfibrillar composites: Effect of aminated graphite platelets coupling
,”
J. Appl. Polym. Sci.
136
,
47660
(
2019
).
64.
Kelnar
,
I.
,
Ü
Bal
,
A.
Ujčič
,
L.
Kaprálková
,
S.
Krejčíková
,
M.
Steinhart
, and
M.
Nofar
, “
Creep behavior of HDPE/PA66 microfibrillar composites modified with graphite nanoplatelets
,”
J. Polym. Res.
27
,
1
7
(
2020
).
65.
Kelnar
,
I.
,
L.
Kaprálková
,
J.
Kratochvíl
,
Z.
Padovec
,
M.
Růžička
, and
J.
Hromádková
, “
Effect of layered silicates and reactive compatibilization on structure and properties of melt-drawn HDPE/PA6 microfibrillar composites
,”
Polym. Bull.
73
,
1673
1688
(
2016
).
66.
Kakroodi
,
A. R.
,
Y.
Kazemi
,
M.
Nofar
, and
C. B.
Park
, “
Tailoring poly(lactic acid) for packaging applications via the production of fully bio-based in situ microfibrillar composite films
,”
Chem. Eng. J.
308
,
772
782
(
2017
).
67.
Fakirov
,
S.
, and
M.
Evstatiev
, “
Microfibrillar reinforced composites? New materials from polymer blends
,”
Adv. Mater.
6
,
395
398
(
1994
).
68.
Evstatiev
,
M.
,
S.
Fakirov
, and
K.
Friedrich
, “
Effect of blend composition on the morphology and mechanical properties of microfibrillar composites
,”
Appl. Compos. Mater.
2
,
93
106
(
1995
).
69.
Evstatiev
,
M.
, and
S.
Fakirov
, “
Microfibrillar reinforcement of polymer blends
,”
Polymer (Guildf.)
33
,
877
880
(
1992
).
70.
Nofar
,
M.
,
A.
Ameli
, and
C. B.
Park
, “
The thermal behavior of polylactide with different D-lactide content in the presence of dissolved CO2
,”
Macromol. Mater. Eng.
299
(
10
),
1232
1239
(
2014
).
71.
Fischer
,
E. W.
,
H. J.
Sterzel
, and
G.
Wegner
, “
Investigation of the structure of solution grown crystals of lactide copolymers by means of chemical reactions
,”
Kolloid Z. Z. Polym.
251
,
980
990
(
1973
).
72.
Wasanasuk
,
K.
,
K.
Tashiro
,
M.
Hanesaka
,
T.
Ohhara
,
K.
Kurihara
,
R.
Kuroki
,
T.
Tamada
,
T.
Ozeki
, and
T.
Kanamoto
, “
Crystal structure analysis of poly(L-lactic acid) α form on the basis of the 2-dimensional wide-angle synchrotron X-ray and neutron diffraction measurements
,”
Macromolecules
44
,
6441
6452
(
2011
).
73.
Wang
,
H.
,
J.
Zhang
, and
K.
Tashiro
, “
Phase transition mechanism of poly(L-lactic acid) among the α, δ, and β forms on the basis of the reinvestigated crystal structure of the β form
,”
Macromolecules
50
,
3285
3300
(
2017
).
74.
Eling
,
B.
,
S.
Gogolewski
, and
A. J.
Pennings
, “
Biodegradable materials of poly(L-lactic acid): 1. Melt-spun and solution-spun fibres
,”
Polymer (Guildf.)
23
,
1587
1593
(
1982
).
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