𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Stereoblock Poly(lactic acid): Synthesis via Solid-State Polycondensation of a Stereocomplexed Mixture of Poly(L-lactic acid) and Poly(D-lactic acid)

✍ Scribed by Kazuki Fukushima; Yukiko Furuhashi; Kazuaki Sogo; Shigenobu Miura; Yoshiharu Kimura

Publisher
John Wiley and Sons
Year
2005
Tongue
English
Weight
155 KB
Volume
5
Category
Article
ISSN
1616-5187

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

Summary: Stereoblock poly(lactic acid) consisting of D‐ and L‐lactate stereosequences can be successfully synthesized by solid‐state polycondensation of a 1:1 mixture of poly(L‐lactic acid) and poly(D‐lactic acid). In the first step, melt‐polycondensation of L‐ and D‐lactic acids is conducted to synthesize poly(L‐lactic acid) and poly(D‐lactic acid) with a medium‐molecular‐weight, respectively. In the next step, these poly(L‐lactic acid) and poly(D‐lactic acid) are melt‐blended in 1:1 ratio to allow formation of their stereocomplex. In the last step, this melt‐blend is subjected to solid‐state polycondensation at temperature where the dehydrative condensation is allowed to promote chain extension in the amorphous phase with the stereocomplex crystals preserved. Finally, stereoblock poly(lactic acid) having high‐molecular‐weight is obtained. The stereoblock poly(lactic acid) synthesized by this way shows a higher melting temperature in consequence of the controlled block lengths and the resulting higher‐molecular‐weight. The product characterization as well as the optimization of the polymerization conditions is described.

Changes in $\overline M _{\rm w}$ of stereoblock poly(lactic acid) (sb‐PLA) as a function of the reaction time.

imageChanges in $\overline M _{\rm w}$ of stereoblock poly(lactic acid) (sb‐PLA) as a function of the reaction time.

📜 SIMILAR VOLUMES

Enhanced Stereocomplex Formation of Poly
Enhanced Stereocomplex Formation of Poly(L-lactic acid) and Poly(D-lactic acid) in the Presence of Stereoblock Poly(lactic acid)
✍ Kazuki Fukushima; Yoon-Hee Chang; Yoshiharu Kimura 📂 Article 📅 2007 🏛 John Wiley and Sons 🌐 English ⚖ 235 KB 👁 1 views

## Abstract Stereoblock poly(lactic acid) (sb‐PLA) is incorporated into a 1:1 polymer blend system of poly(L‐lactic acid) (PLLA) and poly(D‐lactic acid) (PDLA) that has a high molecular weight to study its addition effect on the stereocomplex (sc) formation of PLLA and PDLA. The ternary polymer ble

A Unique Meta-Form Structure in the Ster
A Unique Meta-Form Structure in the Stereocomplex of Poly(D-lactic acid) with Low-Molecular-Weight Poly(L-lactic acid)
✍ Ling Chang; Eamor M. Woo 📂 Article 📅 2010 🏛 John Wiley and Sons 🌐 English ⚖ 350 KB 👁 1 views

## Abstract The crystalline structure and crystallization behavior of PLLA crystals in a 1:1 w/w mixture of low‐MW PLLA with high‐MW PDLA were analyzed using WAXD, DSC, and SAXS. Under cold crystallization, homopolymeric PLLA, appearing as a meta crystal, was discovered in the PDLA/LMW‐PLLA blend.

Microwave-Assisted Single-Step Synthesis
Microwave-Assisted Single-Step Synthesis of Poly(lactic acid) by Direct Polycondensation of Lactic Acid
✍ Ritsuko Nagahata; Daisuke Sano; Hidematsu Suzuki; Kazuhiko Takeuchi 📂 Article 📅 2007 🏛 John Wiley and Sons 🌐 English ⚖ 217 KB

## Abstract The microwave‐assisted direct polycondensation of LA to synthesize PLA has been studied. Microwave irradiation strikingly accelerates the polymerization rate of LA compared to conventional heating. By use of a binary catalyst of SnCl~2~/__p__‐TsOH, PLA with a $\overline M \_{\rm w}$ of

Microwave-Assisted Synthesis of Poly(L-l
Microwave-Assisted Synthesis of Poly(L-lactic acid) via Direct Melt Polycondensation Using Solid Super-Acids
✍ Hai Lei Cao; Peng Wang; Wei Bo Yuan 📂 Article 📅 2009 🏛 John Wiley and Sons 🌐 English ⚖ 207 KB 👁 1 views

## Abstract A microwave‐assisted method of synthesizing high‐molecular‐weight PLA using SSA as green catalyst was developed. Yellowish PLA with $\overline M \_{\rm v}$ above 2.0 × 10^4^ g · mol^−1^ was obtained when the reaction was run at 260 °C within 60 min under microwave irradiation with 0.4 w