In:
Macromolecular Chemistry and Physics, Wiley, Vol. 219, No. 10 ( 2018-05)
Abstract:
Precision synthesis of optically active poly(lactic‐ alt ‐caprolactic acid) is realized using cross‐metathesis polymerization (CMP) and hydrogenation. Enantiopure monomers M L and M D are generated through two consecutive esterification reactions. CMP of these two monomers in different feed ratios, followed by hydrogenation, afford saturated polymers HP L , HP D , and HP DL comprising L‐lactic and/or D‐lactic acid and ε‐caprolactone‐derived motifs with alternating sequences. CMP kinetic analysis by nuclear magnetic resonance (NMR) is performed by employing a racemic monomer M rac . Enantiomeric polyesters HP L and HP D display opposite rotation values and mirror‐imaged cotton effects in circular dichroism (CD) spectra, whereas HP DL derived from equimolar M L and M D shows inactive optical rotation and no CD response. Stereocomplex HP D +HP L is obtained by equimolar mixing of HP L and HP D , since this specimen is the only one to exhibit a sharp melting peak on differential scanning calorimetry (DSC) curve at 45.7 °C. Hence, an amorphous, enantiomerically pure polyester becomes crystalline via stereocomplexation with its complementary enantiomer.
Type of Medium:
Online Resource
ISSN:
1022-1352
,
1521-3935
DOI:
10.1002/macp.v219.10
DOI:
10.1002/macp.201800031
Language:
English
Publisher:
Wiley
Publication Date:
2018
detail.hit.zdb_id:
1475026-0
