Star-Shaped Poly(ether−ester) Block Copolymers:  Synthesis, Characterization, and Their Physical Properties

Biodegradable polymers based on star-shaped poly(ethylene oxide) (PEO)−poly(l-lactide) (PLA) and PEO−poly(ε-caprolactone) (PCL) block copolymers were synthesized by a divergent synthetic method. Multiarm PEOs with various numbers of arms with a fixed molecular weight (MW ∼ 10 000) were synthesized b...

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Bibliographic Details
Published in:Macromolecules 1998-12, Vol.31 (25), p.8766-8774
Main Authors: Choi, Young Kweon, Bae, You Han, Kim, Sung Wan
Format: Article
Language:English
Subjects:
Anionic polymerization
Applied sciences
Biodegradation
Exact sciences and technology
Initiators (chemical)
Molecular weight
Organic polymers
Physicochemistry of polymers
Polyesters
Polyethylene oxides
Polymerization
Preparation, kinetics, thermodynamics, mechanism and catalysts
Ring opening polymerization
Swelling
Synthesis (chemical)
Tin compounds
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Summary:Biodegradable polymers based on star-shaped poly(ethylene oxide) (PEO)−poly(l-lactide) (PLA) and PEO−poly(ε-caprolactone) (PCL) block copolymers were synthesized by a divergent synthetic method. Multiarm PEOs with various numbers of arms with a fixed molecular weight (MW ∼ 10 000) were synthesized by anionic polymerization of ethylene oxide initiated with metalated plurifunctional initiators and used as a core block. The star-shaped block copolymers were prepared by ring-opening polymerization of l-lactide or ε-caprolactone in the presence of multiarm PEOs and a catalytic amount of stannous octoate. The equilibrium swelling and thermal and solution properties of the synthesized star-shaped polymers were examined. The block copolymers were swollen in distilled water, and the degree of swelling decreased as the number of arms increased. The melting point, crystallinity, and phase separation decreased with the degree of branching. A similar tendency in solution viscosity of the star-shaped PEO and block copolymers was found. The results obtained in this study revealed unique properties of star-shaped block polymers which could be useful in the formulation of delivery carrier for polypeptide.
ISSN:0024-9297
1520-5835
DOI:10.1021/ma981069i