Issue 5, 2018

Synthesis, stereocomplex crystallization and homo-crystallization of enantiomeric poly(lactic acid-co-alanine)s with ester and amide linkages

Abstract

α-Hydroxy acid and α-amino acid-derived poly(L-lactic acid-co-L-alanine)s and poly(D-lactic acid-co-D-alanine)s with different alanine unit contents were synthesized by copolymerization of L-lactide and (3S,6S)-3,6-dimethyl-morpholine-2,5-dione and of D-lactide and (3R,6R)-3,6-dimethyl-morpholine-2,5-dione, respectively. The effects of the incorporated alanine units in lactic acid units or amide linkages in ester linkages on the crystallization behavior of solution- and melt-crystallized 50/50 blended samples as well as that of solution- and melt-crystallized nonblended samples were investigated. This article reports for the first time a stereocomplex (SC) formation between enantiomeric random copolyesteramides poly(lactic acid-co-alanine)s with ester and amide linkages. The solution-crystallized nonblended samples crystallized in α- or δ-form homo-crystallites for an L-alanine unit content up to 6 mol% or a D-alanine unit content up to 3 mol%, whereas all the melt-crystallized samples crystallized in α- or δ-form homo-crystallites for the L- or D-alanine unit content at least up to 12 and 13 mol%. In contrast, the solution-crystallized blended samples with the alanine unit contents of 0–13 mol% and the melt-crystallized blended samples with the alanine unit contents of 4–13 mol% crystallized only in SC crystallites, whereas the melt-crystallized blended samples with an alanine unit content of 0 mol% [i.e., poly(L-lactic acid)/poly(D-lactic acid) blends] crystallized in both SC crystallites and homo-crystallites. The alanine units of melt-crystallized nonblended samples were incorporated into homo-crystalline regions, whereas those of solution-crystallized nonblended samples were excluded from homo-crystalline regions. In contrast, the alanine units of solution-crystallized blended samples were incorporated into SC crystalline regions, whereas those of melt-crystallized blended samples were excluded from SC crystalline regions.

Graphical abstract: Synthesis, stereocomplex crystallization and homo-crystallization of enantiomeric poly(lactic acid-co-alanine)s with ester and amide linkages

Supplementary files

Article information

Article type
Paper
Submitted
04 Dec 2017
Accepted
28 Dec 2017
First published
28 Dec 2017

Polym. Chem., 2018,9, 565-575

Synthesis, stereocomplex crystallization and homo-crystallization of enantiomeric poly(lactic acid-co-alanine)s with ester and amide linkages

H. Tsuji, S. Sato, N. Masaki, Y. Arakawa, A. Kuzuya and Y. Ohya, Polym. Chem., 2018, 9, 565 DOI: 10.1039/C7PY02024D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements