Proof of a disentanglement process of aliphatic polyesters via transesterification by evaluation of the growth rate of spherulites

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Abstract

In order to proof the existence of a disentangling pathway of condensation polymers via transesterification, we measured the growth rate of spherulites (G) of poly(L-lactic acid) (PLLA) and poly(e-caprolactone) (PCL) as a function of melt annealing time (At) before isothermal crystallization. We prepared three PLLA samples by means of reaction induced crystallization of oligomers during polymerization. For the sample with unclear crystal habit, we found that G was almost constant at δt <30 min, and then monotonically decreased with increasing δt. On the other hand, for the sample with clear crystal habit, we found that G monotonically decreased with increasing δt. For PCL prepared by bulk polymerization, we found that G shows a plateau at δt <30 min for the samples with a melt annealing temperature of r max= 100 and 130°C. However, it was found that G monotonically decreased at T max= S0°C. From GPC measurements of PLLA and PCL after melt annealing, we confirmed that the molecular weight did not change and molecular weight distribution became broad. These imply that PLLA and PCL have a pathway of disentanglement within the melt via transesterification.

Original languageEnglish
Pages (from-to)475-482
Number of pages8
JournalKobunshi Ronbunshu
Volume66
Issue number10
DOIs
Publication statusPublished - 2009

Fingerprint

spherulite
Polyesters
Transesterification
Lactic acid
annealing
melt
acid
Annealing
Crystallization
polymerization
crystallization
Polymerization
crystal
Crystals
Molecular weight distribution
Oligomers
condensation
Condensation
Polymers
polymer

Keywords

  • Crystallization
  • Entanglement
  • Growth rate
  • PLLA
  • Polyester
  • Transesterification

ASJC Scopus subject areas

  • Polymers and Plastics
  • Environmental Science(all)
  • Materials Science (miscellaneous)
  • Chemical Engineering (miscellaneous)

Cite this

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title = "Proof of a disentanglement process of aliphatic polyesters via transesterification by evaluation of the growth rate of spherulites",
abstract = "In order to proof the existence of a disentangling pathway of condensation polymers via transesterification, we measured the growth rate of spherulites (G) of poly(L-lactic acid) (PLLA) and poly(e-caprolactone) (PCL) as a function of melt annealing time (At) before isothermal crystallization. We prepared three PLLA samples by means of reaction induced crystallization of oligomers during polymerization. For the sample with unclear crystal habit, we found that G was almost constant at δt <30 min, and then monotonically decreased with increasing δt. On the other hand, for the sample with clear crystal habit, we found that G monotonically decreased with increasing δt. For PCL prepared by bulk polymerization, we found that G shows a plateau at δt <30 min for the samples with a melt annealing temperature of r max= 100 and 130°C. However, it was found that G monotonically decreased at T max= S0°C. From GPC measurements of PLLA and PCL after melt annealing, we confirmed that the molecular weight did not change and molecular weight distribution became broad. These imply that PLLA and PCL have a pathway of disentanglement within the melt via transesterification.",
keywords = "Crystallization, Entanglement, Growth rate, PLLA, Polyester, Transesterification",
author = "Shinichi Yamazaki and Takuya Oka and Kunio Kimura",
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journal = "Kobunshi Ronbunshu",
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T1 - Proof of a disentanglement process of aliphatic polyesters via transesterification by evaluation of the growth rate of spherulites

AU - Yamazaki, Shinichi

AU - Oka, Takuya

AU - Kimura, Kunio

PY - 2009

Y1 - 2009

N2 - In order to proof the existence of a disentangling pathway of condensation polymers via transesterification, we measured the growth rate of spherulites (G) of poly(L-lactic acid) (PLLA) and poly(e-caprolactone) (PCL) as a function of melt annealing time (At) before isothermal crystallization. We prepared three PLLA samples by means of reaction induced crystallization of oligomers during polymerization. For the sample with unclear crystal habit, we found that G was almost constant at δt <30 min, and then monotonically decreased with increasing δt. On the other hand, for the sample with clear crystal habit, we found that G monotonically decreased with increasing δt. For PCL prepared by bulk polymerization, we found that G shows a plateau at δt <30 min for the samples with a melt annealing temperature of r max= 100 and 130°C. However, it was found that G monotonically decreased at T max= S0°C. From GPC measurements of PLLA and PCL after melt annealing, we confirmed that the molecular weight did not change and molecular weight distribution became broad. These imply that PLLA and PCL have a pathway of disentanglement within the melt via transesterification.

AB - In order to proof the existence of a disentangling pathway of condensation polymers via transesterification, we measured the growth rate of spherulites (G) of poly(L-lactic acid) (PLLA) and poly(e-caprolactone) (PCL) as a function of melt annealing time (At) before isothermal crystallization. We prepared three PLLA samples by means of reaction induced crystallization of oligomers during polymerization. For the sample with unclear crystal habit, we found that G was almost constant at δt <30 min, and then monotonically decreased with increasing δt. On the other hand, for the sample with clear crystal habit, we found that G monotonically decreased with increasing δt. For PCL prepared by bulk polymerization, we found that G shows a plateau at δt <30 min for the samples with a melt annealing temperature of r max= 100 and 130°C. However, it was found that G monotonically decreased at T max= S0°C. From GPC measurements of PLLA and PCL after melt annealing, we confirmed that the molecular weight did not change and molecular weight distribution became broad. These imply that PLLA and PCL have a pathway of disentanglement within the melt via transesterification.

KW - Crystallization

KW - Entanglement

KW - Growth rate

KW - PLLA

KW - Polyester

KW - Transesterification

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