Reference : SAXS analysis of the morphology of biocompatible and biodegradable poly(ε-caprolactone-b...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Chemistry
Engineering, computing & technology : Materials science & engineering
http://hdl.handle.net/2268/15536
SAXS analysis of the morphology of biocompatible and biodegradable poly(ε-caprolactone-b-glycolide) copolymers1
English
Sobry, R. [University of Liège (ULg) > Department of Physics > Laboratory of Experimental Physics > >]
Van den Bossche, Guy [University of Liège (ULg) > Department of Physics > Laboratory of Experimental Physics > >]
Fontaine, F. [University of Liège (ULg) > Department of Physics > Laboratory of Experimental Physics > >]
Barakat, Ibrahim [University of Liège (ULg) > Department of Chemistry > Center for Education and Research on Macromolecules (CERM) > >]
Dubois, Philippe [University of Liège (ULg) > Department of Chemistry > Center for Education and Research on Macromolecules (CERM) > >]
Jérôme, Robert mailto [Université de Liège - ULg > Department of Chemistry > Center for Education and Research on Macromolecules (CERM) > >]
30-Sep-1996
Journal of Molecular Structure
Elsevier Science Bv
383
1-3
63-68
Yes (verified by ORBi)
International
0022-2860
Amsterdam
[en] ring-opening polymerization (ROP) ; lactone
[en] Poly(epsilon-caprolacrone-b-glycolide) diblock copolyesters have been synthesized by the sequential polymerization of epsilon-caprolactone and glycolide as initiated by aluminium alkoxides. Copolymerization is typically ''living'' and yields copolyesters of perfectly controlled molecular weight and composition. Diblock molecular weight (Mn-PGA+Mn-PCL) ranges from 5700 to 42000 and the rho = Mn-PCL/Mn-PGA ratio varies from 1.5 to 13.1. Due to the inherent insolubility of the polyglycolide (PGA) segment in common organic solvent, the diblock copolyesters form stable non-aqueous colloidal dispersions e.g. in toluene, the stability of which results from the soluble poly(epsilon-caprolactone) (PCL) block. Combining all the experimental observations (PCS, TEM, WAXS, SAXS, AFM), a micelle model has been proposed which consists of a polyglycolide core surrounded with a corona of polycaprolactone (PCL). Both constituents are semi crystalline. From SAXS observations, the PGA core is better described by two concentric spheres. The internal sphere of a 5-6.7 nn diameter would essentially contain crystalline PGA. The diameter of the external sphere, D-PGA, is in the range from 6.2 to 9.6 nm, at least for the investigated diblock copolymers. As a rule, this diameter increases as rho decreases at constant molecular weight and as the diblock molecular weight increases at constant rho. A scattering peak (weak) is observed in the range from 10.8 to 15.5 nm and the Bragg distance is close mu D-PGA, where mu is equal to (1+3 rho/2)(1/3). From steric considerations, mu is the ratio between the diameter of the micelle and the diameter of the PGA core, so that this peak has been assigned to the characteristic intermicellar distance. At very small angles, several additional peaks are the signature of a hyperstructure which is possibly lamellar.
Center for Education and Research on Macromolecules (CERM)
Politique Scientifique Fédérale (Belgique) = Belgian Federal Science Policy ; Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS ; 3M
Researchers
http://hdl.handle.net/2268/15536
10.1016/S0022-2860(96)09269-1
http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6TGS-3VVMKYR-R-7&_cdi=5262&_user=532038&_orig=search&_coverDate=09%2F30%2F1996&_sk=996169998&view=c&wchp=dGLbVzz-zSkzV&md5=7f07513de470568adca877460b9a1ba2&ie=/sdarticle.pdf
http://www.elsevier.com/wps/find/journaldescription.cws_home/500850/description#description
The authors acknowledge Journal of Molecular Structure (Elsevier) for allowing them to archive this paper.

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