Effect of casting solvents on the properties of styrene-butadiene-styrene block copolymers studied by positron annihilation techniques. [Temperature effects]
The positron annihilation technique was used to study the properties of styrene-butadiene-styrene block copolymers obtained by casting them in four different solvents: toluene, carbon tetrachloride, ethyl acetate, and methyl ethyl ketone. The positron annihilation rates plotted as a function of temperature show in all films irregularities at -70 and +85/sup 0/C which were attributed to the onset of motions in the polybutadiene and polystyrene domaines, respectively. In addition to that, two irregularities were observed at -14 and +10/sup 0/C if a poor solvent, such as ethyl acetate or methyl ethyl ketone, was used, while films cast in a good solvent such as toluene or carbon tetrachloride show only one additional irregularity on the lambda/sup 2/-T curves at -14/sup 0/C. The latter results were explained in terms of the interfacial model by assuming that these irregularities correspond to the glass transition of interlayer phases between the pure polystyrene and the pure polybutadiene phases. The one which shows the irregularity at -14/sup 0/C could be the phase in which polybutadiene is the major component, while the transition at +10/sup 0/C can be attributed to a phase in which polystyrene is the dominating factor.
- Research Organization:
- Virginia Polytechnic Inst. and State Univ., Blacksburg
- OSTI ID:
- 5434849
- Journal Information:
- Macromolecules; (United States), Journal Name: Macromolecules; (United States) Vol. 13; ISSN MAMOB
- Country of Publication:
- United States
- Language:
- English
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ACETIC ACID ESTERS
AROMATICS
BETA DECAY
BETA-PLUS DECAY
BUTADIENE
CARBON TETRACHLORIDE
CARBOXYLIC ACID ESTERS
CASTING
CHARGED PARTICLE DETECTION
CHLORINATED ALIPHATIC HYDROCARBONS
COPOLYMERS
DATA
DECAY
DETECTION
DIENES
ESTERS
EXPERIMENTAL DATA
FABRICATION
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROCARBONS
INFORMATION
KETONES
MOLECULAR STRUCTURE
NUMERICAL DATA
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC POLYMERS
PHASE STUDIES
POLYENES
POLYMERS
POSITRON DETECTION
RADIATION DETECTION
SOLVENT PROPERTIES
STYRENE
TOLUENE