Synthesis and characterization of nylon 6/clay nanocomposites prepared by ultrasonication and in situ polymerization

C.P. McAdam, N.E. Hudson, J.J. Liggat, R.A. Pethrick, EPSRC (Funder)

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Nylon 6 nanocomposites were prepared by the in situ polymerization of -caprolactam with ultrasonically dispersed organically modified montmorillonite clay (Cloisite 30B®). Dispersions of the clay platelets with concentrations in the range 1-5 wt % in the monomer were characterized using rheological measurements. All mixtures exhibited shear-thinning, signifying that the clay particles were dispersed as platelets and forming a house of cards structure. Samples with Cloisite concentrations above 2 wt % showed a drop in viscosity between the initial shearing and repeated shearing, indicative of shearing breaking down the initial house of cards structures formed on sonication. DMTA measurements of the samples showed an increase in the -relaxation temperature with increasing clay concentration. The bending modulus, at temperatures below Tg, showed an increase with increasing clay concentration up to 4 wt %. X-ray diffraction measurements showed that all nylon 6/Cloisite 30B samples were exfoliated apart from the 5 wt %, which showed that some intercalated material was present. The nylon crystallized into the -crystalline phase, which is the most thermodynamically stable form. Preference for this form may be a consequence of the long time associated with the postcondensation step in the synthesis or the influence of the platelets on the nucleation step of the crystal growth. DSC measurements showed a retardation of the crystallization rate of nanocomposite samples when compared with that of pure nylon 6, due to the exfoliated clay platelets hindering chain movement. This behavior is different from that observed for the melt-mixed nylon 6/clay nanocomposites, which show an enhancement in the crystallization rate. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
LanguageEnglish
Pages2242-2251
Number of pages9
JournalJournal of Applied Polymer Science
Volume108
Issue number4
DOIs
Publication statusPublished - 15 May 2008

Fingerprint

Nanocomposites
Clay
Polymerization
Platelets
Crystallization
Shearing
Caprolactam
Bentonite
Sonication
Shear thinning
Nylons
nylon 6
clay
Clay minerals
Dispersions
Crystal growth
Nucleation
Monomers
Viscosity
Crystalline materials

Keywords

  • nylon
  • crystallization
  • glass transition
  • nanocomposites
  • clay

Cite this

McAdam, C.P. ; Hudson, N.E. ; Liggat, J.J. ; Pethrick, R.A. ; EPSRC (Funder). / Synthesis and characterization of nylon 6/clay nanocomposites prepared by ultrasonication and in situ polymerization. In: Journal of Applied Polymer Science. 2008 ; Vol. 108, No. 4. pp. 2242-2251.
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Synthesis and characterization of nylon 6/clay nanocomposites prepared by ultrasonication and in situ polymerization. / McAdam, C.P.; Hudson, N.E.; Liggat, J.J.; Pethrick, R.A.; EPSRC (Funder).

In: Journal of Applied Polymer Science, Vol. 108, No. 4, 15.05.2008, p. 2242-2251.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Synthesis and characterization of nylon 6/clay nanocomposites prepared by ultrasonication and in situ polymerization

AU - McAdam, C.P.

AU - Hudson, N.E.

AU - Liggat, J.J.

AU - Pethrick, R.A.

AU - EPSRC (Funder)

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N2 - Nylon 6 nanocomposites were prepared by the in situ polymerization of -caprolactam with ultrasonically dispersed organically modified montmorillonite clay (Cloisite 30B®). Dispersions of the clay platelets with concentrations in the range 1-5 wt % in the monomer were characterized using rheological measurements. All mixtures exhibited shear-thinning, signifying that the clay particles were dispersed as platelets and forming a house of cards structure. Samples with Cloisite concentrations above 2 wt % showed a drop in viscosity between the initial shearing and repeated shearing, indicative of shearing breaking down the initial house of cards structures formed on sonication. DMTA measurements of the samples showed an increase in the -relaxation temperature with increasing clay concentration. The bending modulus, at temperatures below Tg, showed an increase with increasing clay concentration up to 4 wt %. X-ray diffraction measurements showed that all nylon 6/Cloisite 30B samples were exfoliated apart from the 5 wt %, which showed that some intercalated material was present. The nylon crystallized into the -crystalline phase, which is the most thermodynamically stable form. Preference for this form may be a consequence of the long time associated with the postcondensation step in the synthesis or the influence of the platelets on the nucleation step of the crystal growth. DSC measurements showed a retardation of the crystallization rate of nanocomposite samples when compared with that of pure nylon 6, due to the exfoliated clay platelets hindering chain movement. This behavior is different from that observed for the melt-mixed nylon 6/clay nanocomposites, which show an enhancement in the crystallization rate. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

AB - Nylon 6 nanocomposites were prepared by the in situ polymerization of -caprolactam with ultrasonically dispersed organically modified montmorillonite clay (Cloisite 30B®). Dispersions of the clay platelets with concentrations in the range 1-5 wt % in the monomer were characterized using rheological measurements. All mixtures exhibited shear-thinning, signifying that the clay particles were dispersed as platelets and forming a house of cards structure. Samples with Cloisite concentrations above 2 wt % showed a drop in viscosity between the initial shearing and repeated shearing, indicative of shearing breaking down the initial house of cards structures formed on sonication. DMTA measurements of the samples showed an increase in the -relaxation temperature with increasing clay concentration. The bending modulus, at temperatures below Tg, showed an increase with increasing clay concentration up to 4 wt %. X-ray diffraction measurements showed that all nylon 6/Cloisite 30B samples were exfoliated apart from the 5 wt %, which showed that some intercalated material was present. The nylon crystallized into the -crystalline phase, which is the most thermodynamically stable form. Preference for this form may be a consequence of the long time associated with the postcondensation step in the synthesis or the influence of the platelets on the nucleation step of the crystal growth. DSC measurements showed a retardation of the crystallization rate of nanocomposite samples when compared with that of pure nylon 6, due to the exfoliated clay platelets hindering chain movement. This behavior is different from that observed for the melt-mixed nylon 6/clay nanocomposites, which show an enhancement in the crystallization rate. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

KW - nylon

KW - crystallization

KW - glass transition

KW - nanocomposites

KW - clay

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EP - 2251

JO - Journal of Applied Polymer Science

T2 - Journal of Applied Polymer Science

JF - Journal of Applied Polymer Science

SN - 0021-8995

IS - 4

ER -