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Deformation and alignment of lamellae in melt extension of blends of a styrene‐butadiene block copolymer with polystyrene
Author(s) -
Handge Ulrich A.,
Buschnakowski Matthias,
Michler Goerg H.
Publication year - 2009
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.29601
Subject(s) - materials science , copolymer , polystyrene , elongation , composite material , lamellar structure , thermoplastic elastomer , polymer blend , phase (matter) , polymer , polymer chemistry , ultimate tensile strength , chemistry , organic chemistry
The development of the morphology and the alignment of lamellae in melt elongation of blends of an asymmetric linear styrene‐butadiene block copolymer (LN3) and polystyrene (PS 158K) was investigated. PS 158K and LN3 formed two‐phase polymer blends with PS 158K resp. LN3 inclusions, depending on the concentration of polystyrene. The block copolymer was arranged in a lamellar phase with a lamellae thickness of ∼ 13 nm. Our rheological experiments revealed that the complex modulus, the elongational viscosity and the recovered stretch of the blends primarily resulted from a superposition of the properties of the blend components. In melt elongation, pure LN3 started to crumple at a small Hencky strain. In the blends, the presence of the PS 158K inclusions led to a macroscopically more uniform elongation, but with an anisotropic Poisson ratio. The LN3 inclusions in the PS 158K matrix were deformed into a filament‐like shape. In the blends with a LN3 matrix the alignment of the block copolymer lamellae parallel to the loading direction increased with applied extensional strain. In the latter case, the lamellae thickness did not decrease significantly. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009