Chemical Modification, Thermal Characterization and Dielectric Spectroscopy of Polystyrene-block-Polyisoprene Diblock Copolymers

In this work, synthesis and chemical modification of a polystyrene‐block‐polyisoprene (PS‐b‐PI) diblock copolymer is presented. The modification reactions result in hydroxyl, amine, and carboxyl end‐functional groups, respectively. Thermal analysis reveals a shift of the glass transition temperature...

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Bibliographic Details
Published in:Macromolecular chemistry and physics 2016-06, Vol.217 (11), p.1293-1304
Main Authors: Georgopanos, Prokopios, Filiz, Volkan, Handge, Ulrich A., Abetz, Volker
Format: Article
Language:English
Subjects:
Block copolymers
Blocking
chemical modification
Copolymers
diblock copolymers
Dielectric relaxation
dielectric spectroscopy
functional groups
Glass
Glass transition temperature
Polystyrene resins
segmental relaxation
Spectrum analysis
Temperature
Thermal analysis
Thermal properties
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Summary:In this work, synthesis and chemical modification of a polystyrene‐block‐polyisoprene (PS‐b‐PI) diblock copolymer is presented. The modification reactions result in hydroxyl, amine, and carboxyl end‐functional groups, respectively. Thermal analysis reveals a shift of the glass transition temperature of the polystyrene block to lower temperatures with respect to the polystyrene precursor because of the partial miscibility of the PS and the PI blocks. Comparing the glass transition temperature of the PS block of the three different end‐functionalized diblock copolymers, the analysis in this work shows that a large end‐group (i.e., the amine end‐group) yields a lower glass transition temperature of the polystyrene block. The modified diblock copolymers were characterized by means of broadband dielectric spectroscopy in order to compare the results of thermal analysis and to monitor the dielectric relaxation behavior which is associated with the different end‐functional groups. Comparing the dielectric loss of the pristine and the functionalized diblock copolymers, the segmental relaxation of the PS microphase is significantly influenced by the presence of these polar end‐functional groups. A low molecular weight polystyrene‐block‐polyisoprene (PS‐b‐PI) diblock copolymer is synthesized and functionalized with different end‐groups (OH, NH2, and COOH). End‐functionalization of the PI block influences the thermal properties (glass transition of polystyrene) and the segmental relaxation of the polystyrene block.
ISSN:1022-1352
1521-3935
DOI:10.1002/macp.201500528