Abstract
The crystal structure formed upon stretching or stroking of poly(L-lactide) is determined by electron diffraction and conformational energy analysis. It rests on a frustrated packing of three three-fold helices in a trigonal unit-cell of parameters a = b = 1.052 nm, c = 0.88 nm, space group P32. The frustrated packing is of the type described as North-South-South (NSS). This structure appears to be formed to accommodate the random up-down orientation of neighbor chains associated with rapid crystallization conditions. This randomness introduces structural disorder (c-axis shifts and azimuthal setting of neighbor helices). The resultant streaking of the diffraction pattern is modeled. Frustrated packings observed in polymeric systems that depart from three-fold symmetry, and in pseudo-racemates of low molecular weight compounds are discussed. (C) 2000 Elsevier Science Ltd.
Original language | English |
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Pages (from-to) | 8921-8930 |
Number of pages | 10 |
Journal | polymer |
Volume | 41 |
Issue number | 25 |
DOIs | |
Publication status | Published - Sept 8 2000 |
Externally published | Yes |
Keywords
- Crystal structure
- Frustration
- Polylactide
ASJC Scopus subject areas
- Organic Chemistry
- Polymers and Plastics
- Materials Chemistry