High Tm poly(L-lactide)s via REP or ROPPOC of l-lactide. Issue 12 (25th February 2020)

• Record Type: Journal Article
• Authors: Kricheldorf, Hans R.; Weidner, Steffen M.; Meyer, Andreas
• Is Part Of: Polymer chemistry. Volume 11:Issue 12(2020)
• Page Start: 2182
• Page End: 2193
• Publication Date: 2020-02-25
• Subjects: Polymers -- Periodicals; Macromolecules -- Periodicals; Polymerization -- Periodicals; 547.705
• DOI: 10.1039/c9py01908a
• Languages: English
• ISSNs: 1759-9954

Abstract

Abstract : A new kind of high melting (H T m ) pol(l -lactide) was discovered when cyclic poly(l -lactide)s were prepared by ring-expansion polymerization with cyclic tin catalysts at 130–160 °C in bulk. Abstract : A new kind of high melting (H T m ) pol(l -lactide) was discovered when cyclic poly(l -lactide)s were prepared by ring-expansion polymerization with cyclic tin catalysts at 130–160 °C in bulk. By DSC measurements with 10 K min −1 melting temperatures ( T m ) in the range of 190–196 °C were found. The WAXS and SAXS measurements evidenced that not a new crystal lattice but a well-ordered morphology and a higher perfection of the crystallites are responsible for the high T m values and high crystallinities. Under identical reaction conditions SnOct2 -catalyzed and alcohol-initiated ROPs do not yield these crystallites. Furthermore, it was found that the standard crystallites are kinetically favored upon rapid crystallization, whereas the high melting form of poly(l -lactide) is thermodynamically more stable.