Complex Crystal Formation of Poly(L-lactide) with Solvent Molecules
| Autor: | Masao Sumita, Shigeo Asai, Hironori Marubayashi |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Materials science
Polymers and Plastics Organic Chemistry High selectivity Crystal structure law.invention Inorganic Chemistry Solvent chemistry.chemical_compound Crystallography chemistry law Poly-L-lactide Materials Chemistry Organic chemistry Molecule Orthorhombic crystal system Crystallization Tetrahydrofuran |
| Zdroj: | Macromolecules. 45(No. 3):1384-1397 |
| Popis: | By screening examinations for a wide variety of organic solvents, we found that poly(l-lactide) (PLLA) forms the crystalline complex (e-form) with the specific organic solvents such as tetrahydrofuran (THF) and N,N-dimethylformamide (DMF) below room temperature. It was revealed that PLLA has high selectivity for low molecular weight compounds to form the e-crystals. By fiber diagram analyses for the e-forms, it was found that PLLA chains take the 107 (left-handed 103) helical conformation and are packed in the orthorhombic lattice (a = 1.5–1.6 nm, b = 1.2–1.3 nm, c = 2.8–2.9 nm, and α = β = γ = 90°). Based on R-factor and packing energy calculations, the plausible crystal structure of PLLA–DMF complex was proposed, in which four PLLA chains and eight guest solvents are packed in the unit cell. |
| Databáze: | OpenAIRE |
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