| Plastic deformation of amorphous poly(L/DL-lactide): structure evolution and physical properties. | |
| | |
MedLine Citation:
|
PMID: 17472336 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Plastic deformation of amorphous, thermally noncrystallizable poly(L/DL-lactide) 70/30 (P(L/DL)LA) was induced by a plane-strain compression in a channel-die at different temperatures, above the glass transition (Tg) from 60 to 90 degrees C. Samples undeformed (reference) and deformed to different compression ratios, from 4.6 to 23.0, were studied by X-ray diffraction, thermally modulated differential scanning calorimetry, light microscopy, and mechanical methods-viscoelastic and tensile tests. The effects of the compression ratios and deformation temperatures on the final structure and properties of the P(L/DL)LA were evaluated. It was revealed that plastic deformation transformed an amorphous P(L/DL)LA (thermally noncrystallizable) to a crystalline fibrillar texture oriented in the flow direction. Fibrillar texture was formed in spite of the tendency of the plane-strain compression to form single-crystal-like texture. The crystallite size in the transverse direction was small, up to 90 angstroms at the highest compression ratio. No evidence of lamellar organization and features of supermolecular structure were detected by small-angle X-ray scattering and light microscopy, respectively. The oriented samples exhibited a low crystallinity degree at the level of 6-9% at the highest compression ratio. The main transformation mechanism was shear and orientation-induced crystallization. The crystalline phase was in the alpha crystallographic modification of poly(lactide) typically formed in more stereoregular poly(lactide) by thermal treatment. The glass transition increased with the increase of compression ratio reflecting the increase of orientation of the polymer chains. The tensile strength of deformed samples was improved considerably in comparison to that of the reference sample. |
| | |
Authors:
|
Miroslaw Pluta; Andrzej Galeski |
Related Documents
:
|
9456516 - Plasticity of neuronal response properties in adult cat striate cortex. 10195386 - Orientation variance as a quantifier of structure in texture. 23125346 - Physiological and agonistic behavioural response of procambarus clarkii to an acoustic ... 1673246 - Horizontal-vertical filters in early vision predict anomalous line-orientation identifi... 23028786 - Dealing with illumination in visual scenes: effects of ageing and alzheimer's disease. 9450386 - Circadian locomotor rhythms in the cricket, gryllodes sigillatus. ii. interactions betw... |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2007-05-02 |
Journal Detail:
|
Title: Biomacromolecules Volume: 8 ISSN: 1525-7797 ISO Abbreviation: Biomacromolecules Publication Date: 2007 Jun |
Date Detail:
|
Created Date: 2007-06-11 Completed Date: 2007-08-09 Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 100892849 Medline TA: Biomacromolecules Country: United States |
Other Details:
|
Languages: eng Pagination: 1836-43 Citation Subset: IM |
Affiliation:
|
Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland. mpluta@bilbo.cbmm.lodz.pl |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Biocompatible Materials
/
chemistry Calorimetry, Differential Scanning Crystallization Elasticity Light Macromolecular Substances Molecular Conformation Plastics Polyesters / chemistry* Polymers / chemistry Stress, Mechanical Temperature Tensile Strength X-Ray Diffraction X-Rays |
| Chemical | |
Reg. No./Substance:
|
0/Biocompatible Materials; 0/Macromolecular Substances; 0/Plastics; 0/Polyesters; 0/Polymers; 26969-66-4/poly(lactide) |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Structure study of cellulose fibers wet-spun from environmentally friendly NaOH/urea aqueous solutio...
Next Document: Adsorption of plasmid DNA onto N,N'- (dimethylamino)ethyl-methacrylate graft-polymerized poly-L-lact...