Isothermal Flow-Induced Crystallization of Polyamide 66 Melts

Jiho Seo, Hideaki Takahashi, Behzad Nazari, Alicyn M. Rhoades, Richard P. Schaake, Ralph H. Colby

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

When the molten state of a semicrystalline polymer is subjected to sufficiently intense flow before crystallization, the crystallization kinetics are accelerated and the crystalline superstructure is transformed from spherulites to smaller anisotropic structures. In this study, flow-induced crystallization (FIC) of polyamide 66 (PA 66) was investigated using rheology and polarized optical microscopy. After an interval of shear flow at 270 °C, above the melting temperature (Tm = 264 °C) and below the equilibrium melting temperature, small-amplitude oscillatory shear time sweeps at 245 °C were used to monitor FIC kinetics. As specific work was imposed on a PA 66 melt at 270 °C from 10 Pa to 40 kPa, the onset of crystallization at 245 °C did not change. Above the critical work of 40 kPa up to 100 MPa, the onset of crystallization at 245 °C was progressively shifted from 628 to 26 s, as the applied specific work was increased. For quantitative analysis of the acceleration, the Avrami equation was used with Pogodina's storage modulus normalization method, revealing the transition of Avrami exponent from ∼3 to ∼2 at the critical specific work of ∼40 kPa. Strong FIC acceleration was observed after the transition. After applying very low shear rates, large spherulites were observed without cylindrites, while a mixture of small spherulites and large anisotropic cylindrites was seen after applying a shear rate of 10 s-1.

Original languageEnglish (US)
Pages (from-to)4269-4279
Number of pages11
JournalMacromolecules
Volume51
Issue number11
DOIs
StatePublished - Jun 12 2018

Fingerprint

Nylons
Crystallization
Polyamides
Crystallization kinetics
Shear deformation
Melting point
Shear flow
Rheology
Optical microscopy
Molten materials
Polymers
Elastic moduli
Crystalline materials
Chemical analysis

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

Cite this

Seo, Jiho ; Takahashi, Hideaki ; Nazari, Behzad ; Rhoades, Alicyn M. ; Schaake, Richard P. ; Colby, Ralph H. / Isothermal Flow-Induced Crystallization of Polyamide 66 Melts. In: Macromolecules. 2018 ; Vol. 51, No. 11. pp. 4269-4279.
@article{6a6b0087157849f99fca929f4b597848,
title = "Isothermal Flow-Induced Crystallization of Polyamide 66 Melts",
abstract = "When the molten state of a semicrystalline polymer is subjected to sufficiently intense flow before crystallization, the crystallization kinetics are accelerated and the crystalline superstructure is transformed from spherulites to smaller anisotropic structures. In this study, flow-induced crystallization (FIC) of polyamide 66 (PA 66) was investigated using rheology and polarized optical microscopy. After an interval of shear flow at 270 °C, above the melting temperature (Tm = 264 °C) and below the equilibrium melting temperature, small-amplitude oscillatory shear time sweeps at 245 °C were used to monitor FIC kinetics. As specific work was imposed on a PA 66 melt at 270 °C from 10 Pa to 40 kPa, the onset of crystallization at 245 °C did not change. Above the critical work of 40 kPa up to 100 MPa, the onset of crystallization at 245 °C was progressively shifted from 628 to 26 s, as the applied specific work was increased. For quantitative analysis of the acceleration, the Avrami equation was used with Pogodina's storage modulus normalization method, revealing the transition of Avrami exponent from ∼3 to ∼2 at the critical specific work of ∼40 kPa. Strong FIC acceleration was observed after the transition. After applying very low shear rates, large spherulites were observed without cylindrites, while a mixture of small spherulites and large anisotropic cylindrites was seen after applying a shear rate of 10 s-1.",
author = "Jiho Seo and Hideaki Takahashi and Behzad Nazari and Rhoades, {Alicyn M.} and Schaake, {Richard P.} and Colby, {Ralph H.}",
year = "2018",
month = "6",
day = "12",
doi = "10.1021/acs.macromol.8b00082",
language = "English (US)",
volume = "51",
pages = "4269--4279",
journal = "Macromolecules",
issn = "0024-9297",
publisher = "American Chemical Society",
number = "11",

}

Isothermal Flow-Induced Crystallization of Polyamide 66 Melts. / Seo, Jiho; Takahashi, Hideaki; Nazari, Behzad; Rhoades, Alicyn M.; Schaake, Richard P.; Colby, Ralph H.

In: Macromolecules, Vol. 51, No. 11, 12.06.2018, p. 4269-4279.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Isothermal Flow-Induced Crystallization of Polyamide 66 Melts

AU - Seo, Jiho

AU - Takahashi, Hideaki

AU - Nazari, Behzad

AU - Rhoades, Alicyn M.

AU - Schaake, Richard P.

AU - Colby, Ralph H.

PY - 2018/6/12

Y1 - 2018/6/12

N2 - When the molten state of a semicrystalline polymer is subjected to sufficiently intense flow before crystallization, the crystallization kinetics are accelerated and the crystalline superstructure is transformed from spherulites to smaller anisotropic structures. In this study, flow-induced crystallization (FIC) of polyamide 66 (PA 66) was investigated using rheology and polarized optical microscopy. After an interval of shear flow at 270 °C, above the melting temperature (Tm = 264 °C) and below the equilibrium melting temperature, small-amplitude oscillatory shear time sweeps at 245 °C were used to monitor FIC kinetics. As specific work was imposed on a PA 66 melt at 270 °C from 10 Pa to 40 kPa, the onset of crystallization at 245 °C did not change. Above the critical work of 40 kPa up to 100 MPa, the onset of crystallization at 245 °C was progressively shifted from 628 to 26 s, as the applied specific work was increased. For quantitative analysis of the acceleration, the Avrami equation was used with Pogodina's storage modulus normalization method, revealing the transition of Avrami exponent from ∼3 to ∼2 at the critical specific work of ∼40 kPa. Strong FIC acceleration was observed after the transition. After applying very low shear rates, large spherulites were observed without cylindrites, while a mixture of small spherulites and large anisotropic cylindrites was seen after applying a shear rate of 10 s-1.

AB - When the molten state of a semicrystalline polymer is subjected to sufficiently intense flow before crystallization, the crystallization kinetics are accelerated and the crystalline superstructure is transformed from spherulites to smaller anisotropic structures. In this study, flow-induced crystallization (FIC) of polyamide 66 (PA 66) was investigated using rheology and polarized optical microscopy. After an interval of shear flow at 270 °C, above the melting temperature (Tm = 264 °C) and below the equilibrium melting temperature, small-amplitude oscillatory shear time sweeps at 245 °C were used to monitor FIC kinetics. As specific work was imposed on a PA 66 melt at 270 °C from 10 Pa to 40 kPa, the onset of crystallization at 245 °C did not change. Above the critical work of 40 kPa up to 100 MPa, the onset of crystallization at 245 °C was progressively shifted from 628 to 26 s, as the applied specific work was increased. For quantitative analysis of the acceleration, the Avrami equation was used with Pogodina's storage modulus normalization method, revealing the transition of Avrami exponent from ∼3 to ∼2 at the critical specific work of ∼40 kPa. Strong FIC acceleration was observed after the transition. After applying very low shear rates, large spherulites were observed without cylindrites, while a mixture of small spherulites and large anisotropic cylindrites was seen after applying a shear rate of 10 s-1.

UR - http://www.scopus.com/inward/record.url?scp=85048461621&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85048461621&partnerID=8YFLogxK

U2 - 10.1021/acs.macromol.8b00082

DO - 10.1021/acs.macromol.8b00082

M3 - Article

AN - SCOPUS:85048461621

VL - 51

SP - 4269

EP - 4279

JO - Macromolecules

JF - Macromolecules

SN - 0024-9297

IS - 11

ER -