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The entanglement plateau in the dynamic modulus of rubbery styrene–diene block copolymers. Significance to pressure‐sensitive adhesive formulations
Author(s) -
Kraus G.,
Rollmann K. W.
Publication year - 1977
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1977.070211210
Subject(s) - materials science , copolymer , polystyrene , diluent , compatibility (geochemistry) , adhesive , composite material , styrene , plasticizer , dynamic mechanical analysis , quantum entanglement , modulus , isoprene , polymer chemistry , polymer , chemistry , organic chemistry , layer (electronics) , physics , quantum mechanics , quantum
Styrene–diene (butadiene or isoprene) block copolymers of the SDS or $ ({\rm SD\rlap{--} )} $ type exhibit a plateau in the dynamic storage modulus located between the glass transitions of the polydiene and polystyrene domains. When the polydiene is the continuous phase, the height of this plateau can be estimated with good success from the entanglement spacing molecular weight of the polydiene and the filler effect of the polystyrene domains. The effect of introduction of a center block‐compatible diluent can also be calculated, although the simple procedure used here tends to underestimate the plasticizer effect, particularly at high diluent concentration. Nevertheless, the calculation furnishes a useful criterion of compatibility of the polydiene center blocks and low molecular weight resins used commonly as tackifiers in pressure‐sensitive adhesives. Center block compatibility is essential for the development of tack in these compositions.