Use of Non‐isothermal DSC in Comparative Studies of Tin(II) Systems for the Ring‐Opening Polymerization of D‐lactide

Sawarot Phetsuk, Robert Molloy, Paul D. Topham, Brian J. Tighe, Puttinan Meepowpan, Wanich Limwanich, Winita Punyodom

Research output: Contribution to journalArticlepeer-review


Understanding the kinetics and mechanisms of polymerization, particularly the role of a catalyst or initiator used, allows for the manipulation and control of the fabrication of new materials by the most convenient, straightforward routes. The kinetics of the bulk ring-opening polymerization (ROP) of d-lactide, a useful monomer employed to control the properties of poly(l-lactide), have been studied herein to identify a relatively quick (1 h), controlled, yet convenient route to moderately high molecular weight poly(d-lactide). Tin(II) octoate (Sn(Oct) 2), Sn(Oct) 2/n-butanol (nBuOH) and liquid tin(II) butoxide (Sn(OnBu) 2) as initiating systems were investigated by non-isothermal differential scanning calorimetry (DSC). Isoconversional methods were employed to determine the activation energy (E a) for each reaction. The results showed that liquid Sn(OnBu) 2 was a more efficient initiator than the commonly reported initiating systems of Sn(Oct) 2 and Sn(Oct) 2/nBuOH in terms of producing higher polymerization rates and polymer molecular weights. High-molecular-weight poly(d-lactide) (1.8 × 10 5 Da) with moderate dispersity (Р= 1.3) was obtained using 0.1 mol% liquid Sn(OnBu) 2 as the initiator at 120 °C. This work describes the applications of non-isothermal DSC and isoconversional methods in comparing the effectiveness of different initiators in the bulk ROP of d-lactide for the first time.

Original languageEnglish
Pages (from-to)949-956
JournalPolymer International
Issue number10
Early online date25 Feb 2023
Publication statusPublished - Oct 2023

Bibliographical note

Copyright © 2023 Society of Chemical Industry. This is the peer reviewed version of the following article: Phetsuk, S. et al (2023), Use of Non-isothermal DSC in Comparative Studies of Tin(II) Systems for the Ring-Opening Polymerization of D-lactide. Polym Int. Accepted Author Manuscript. Which has been published in final form at This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.

Funding Information:
SP wishes to thank the Research Professional Development Project under the Science Achievement Scholarship of Thailand (SAST) for the provision of a PhD scholarship and also the Graduate School, Chiang Mai University. This research work was partially supported by the Center of Excellence in Materials Science and Technology, Chiang Mai University and the European Union's Horizon 2020 research and innovation program under Marie Sklodowska‐Curie grant agreement no. 871650 (MEDIPOL).


  • d-lactide
  • liquid tin(II) butoxide
  • non-isothermal DSC
  • ring-opening polymerization


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