Online citations, reference lists, and bibliographies.
← Back to Search

Unexpected Shear Dependence Of Pressure-induced γ-crystals In Isotactic Polypropylene

Shu-Gui Yang, Zheng-Chi Zhang, Liang-qing Zhang, D. Zhou, Y. Wang, J. Lei, L. Li, Z. Li
Published 2015 · Materials Science

Save to my Library
Download PDF
Analyze on Scholarcy
Share
Flow and pressure frequently coexist in practical polymer processing operations, but their combined influence on the microstructure of polymer parts has received very limited attention in the academic community. In the current work, we utilized a home-made pressuring and shearing device with a reliable dynamic sealing design to study the formation and microstructure of γ-form isotactic polypropylene (iPP) obtained under the coexistence of flow and pressure. We observed a strong shear dependence of pressure-induced γ-form iPP. There are three regions depending on shear flow intensity, i.e., facilitation ( 9.1 s−1) regions of the γ-form. As the shear rate is below 3.7 s−1, the pressure-induced γ-form dominates and the shear flow slightly facilitates formation of γ-form. Unexpectedly, above 3.7 s−1, the shear flow is unfavorable for γ-form growth. Even under a pressure of 100 MP, a flow field with a shear rate above 9.1 s−1 could entirely suppress the γ-form. Moreover, we did not observe any trace of the β-form in the obtained iPP that is generally generated under shear flow alone. These interesting results have never been reported, which undoubtedly help manipulate the inner structure and thus enhance the performance of final iPP products.
This paper references
10.1021/MA00220A014
γ-Isotactic polypropylene. A structure with nonparallel chain axes
S. V. Meille (1990)
10.1021/MZ3000978
Oriented gamma phase in isotactic polypropylene homopolymer
Tim B. van Erp (2012)
10.1016/J.POLYMER.2012.08.003
Quantification of non-isothermal, multi-phase crystallization of isotactic polypropylene: the influence of cooling rate and pressure
Van Drongelen (2012)
10.1016/S0079-6700(00)00046-0
Microstructure of polypropylene
V. Busico (2001)
10.1016/0032-3861(82)90110-0
An improved permanganic etchant for polyolefines
R. H. Olley (1982)
10.1021/MA00074A013
Contact faces of epitaxially crystallized .alpha.- and .gamma.-phase isotactic polypropylene observed by atomic force microscopy
W. Stocker (1993)
10.1021/MA981849R
Structural and Kinetic Factors Governing the Formation of the γ Polymorph of Isotactic Polypropylene
R. Alamo (1999)
10.1021/MA035295Q
Comparison between Polymorphic Behaviors of Ziegler−Natta and Metallocene-Made Isotactic Polypropylene: The Role of the Distribution of Defects in the Polymer Chains
C. Rosa (2004)
10.1103/PHYSREVLETT.100.048302
Crystallization and dissolution of flow-induced precursors.
L. Balzano (2008)
10.1002/MARC.1997.030180101
On the crystallization of γ-isotactic polypropylene: A high pressure study
S. Brückner (1997)
10.1063/1.1655891
Crystallization of Low‐Molecular‐Weight Polypropylene Fractions
D. Morrow (1968)
10.1016/J.POLYMER.2004.02.071
Lamellar morphology of random metallocene propylene copolymers studied by atomic force microscopy
Ian L. Hosier (2004)
10.1038/340455A0
Non-parallel chains in crystalline γ-isotactic polypropylene
S. V. Meille (1989)
10.1021/jp400847p
Crystalline structure changes in preoriented metallocene-based isotactic polypropylene upon annealing.
Y. Wang (2013)
10.1021/jp1002484
Spatial distribution of gamma-crystals in metallocene-made isotactic polypropylene crystallized under combined thermal and flow fields.
Y. Wang (2010)
10.1021/MA951168L
α-γ disorder in isotactic polypropylene crystallized under high pressure
S. V. Meille (1996)
10.1016/0032-3861(91)90185-L
Single crystals of γ phase isotactic polypropylene: combined diffraction and morphological support for a structure with non-parallel chains
B. Lotz (1991)
10.1063/1.1734985
Spherulitic Crystallization in Polypropylene
F. J. Padden (1959)
10.1021/MA020648R
Crystallization of Metallocene-Made Isotactic Polypropylene: Disordered Modifications Intermediate between the α and γ Forms
F. Auriemma (2002)
10.1016/0032-3861(61)90021-0
Polymorphism of crystalline polypropylene
E. J. Addink (1961)
10.1016/0079-6700(91)90023-E
Polymorphism in isotactic polypropylene
S. Brückner (1991)
10.1021/MA00218A021
Structure and rheology of aramid solutions: x-ray scattering measurements
S. Picken (1990)
10.1039/F29787401802
Dynamics of concentrated polymer systems. Part 2.—Molecular motion under flow
M. Doi (1978)
10.1016/0032-3861(96)00370-9
Structure and morphology of poly(propylenes): a molecular analysis
B. Lotz (1996)
10.1007/BF02731859
Structure and properties of isotactic polypropylene
G. Natta (1960)
10.1021/MA025948N
Correlation of Material and Processing Time Scales with Structure Development in Isotactic Polypropylene Crystallization
A. Elmoumni (2003)
10.1002/MACP.1964.020750113
Crystalline forms of isotactic polypropylene
A. T. Jones (1964)
10.1021/MA0605907
Plastic Deformation of the γ Phase in Isotactic Polypropylene in Plane-Strain Compression
E. Lezak (2006)
10.1016/S0032-3861(97)10121-5
The γ-phase of high molecular weight isotactic polypropylene: III. The equilibrium melting point and the phase diagram
K. Mezghani (1998)
10.1016/0032-3861(71)90045-0
The melting behaviour of heat crystallized poly(ethylene terephthalate)
P. J. Holdsworth (1971)
10.1016/J.MECHMAT.2013.05.010
The role of dislocations in γ-iPP under plastic deformation investigated by X-ray line profile analysis
Gerald Polt (2013)
10.1002/POLB.1986.090240909
Crystal morphology of the γ (triclinic) phase of isotactic polypropylene and its relation to the α phase
B. Lotz (1986)
10.1021/jp3003068
Suppressing of γ-crystal formation in metallocene-based isotactic polypropylene during isothermal crystallization under shear flow.
Y. Wang (2012)
10.1021/MA900475H
Epitaxially Dominated Crystalline Morphologies of the γ-Phase in Isotactic Polypropylene
Y. Cao (2009)
10.1016/S0032-3861(97)00131-6
The γ-phase of high molecular weight isotactic polypropylene. II: The morphology of the γ-form crystallized at 200 MPa
K. Mezghani (1997)
10.1021/MA951885F
On the γ-Phase of Isotactic Polypropylene
R. Thomann (1996)
10.1063/1.1734986
Evidence for a Second Crystal Form of Polypropylene
H. Keith (1959)



This paper is referenced by
10.1002/APP.46378
Flow‐induced crystallization of polylactide stereocomplex under pressure
Y. Song (2018)
10.1021/ACS.MACROMOL.7B00041
Window of Pressure and Flow To Produce β-Crystals in Isotactic Polypropylene Mixed with β-Nucleating Agent
Shu-Gui Yang (2017)
10.1016/J.POLYMER.2017.11.040
An unusual promotion of γ-crystals in metallocene-made isotactic polypropylene from orientational relaxation and favorable temperature window induced by shear
Yan Wang (2018)
10.1021/ACS.MACROMOL.5B01043
Flow and Pressure Jointly Induced Ultrahigh Melting Temperature Spherulites with Oriented Thick Lamellae in Isotactic Polypropylene
Shu-Gui Yang (2015)
10.1021/ACS.MACROMOL.6B00595
Dominant β-Form of Poly(l-lactic acid) Obtained Directly from Melt under Shear and Pressure Fields
Jia-Feng Ru (2016)
10.1021/acs.macromol.7b00595
Full Characterization of Multiphase, Multimorphological Kinetics in Flow-Induced Crystallization of IPP at Elevated Pressure
E. Troisi (2017)
10.1002/PCR2.10035
A revisit to the flow and pressure jointly induced thick lamellae in isotactic polypropylene: A synchrotron radiation small‐ and wide‐angle X‐ray scattering study
Shu-Gui Yang (2019)
10.1021/acsomega.8b02425
Flow-Induced Precursor Formation of Poly(l-lactic acid) under Pressure
Y. Song (2018)
10.1021/acs.jpcb.7b02241
Thicker Lamellae and Higher Crystallinity of Poly(lactic acid) via Applying Shear Flow and Pressure and Adding Poly(ethylene Glycol).
Jia-Feng Ru (2017)
10.1002/marc.201700407
A Criterion for Flow-Induced Oriented Crystals in Isotactic Polypropylene under Pressure.
Shu-Gui Yang (2017)
10.1007/s10118-018-2057-3
Distribution of α-, β-, and γ-Phases in a Multi-flow Injection-molded Hierarchical Structure
Dashan Mi (2018)
10.1002/PCR2.10059
Role of pressure in flow‐induced shish‐kabab in binary blend of long‐ and short‐chain Polyethylenes
X. Zhang (2019)
10.1016/J.POLYMER.2019.121641
Role of lamellar thickening in thick lamellae formation in isotactic polypropylene when crystallizing under flow and pressure
Shu-Gui Yang (2019)
10.1021/acs.chemrev.7b00500
Multiscale and Multistep Ordering of Flow-Induced Nucleation of Polymers.
Kunpeng Cui (2018)
10.1002/PI.5368
Synergistic enhancement of crystallization and mechanical performance of polypropylene random copolymer by strong shear and β‐nucleating agent
Y. Qi (2017)
Structuring of polyolefins during processing conditions
Em Enrico Troisi (2017)
10.1021/ACS.IECR.8B00708
Concomitant Crystallization in Propylene/Ethylene Random Copolymer with Strong Flow at Elevated Temperatures
L. Zheng (2018)
10.1007/s10965-018-1632-1
Reinforcing and toughening isotactic polypropylene through shear-induced crystallization and β-nucleating agent induced crystallization
Guanglong Wang (2018)
10.1002/PCR2.10002
Quantification of pressure‐induced γ‐crystals in isotactic polypropylene: The influence of shear and carbon nanotubes
Jian‐Mei Lin (2018)
10.1016/J.POLYMER.2018.01.081
Influence of nucleating agent self-assembly on structural evolution of isotactic polypropylene during uniaxial stretching
Baobao Chang (2018)
Semantic Scholar Logo Some data provided by SemanticScholar