Title of article :
Formation of phase structure and crystallization behavior in blends containing polystyrene–polyethylene block copolymers
Author/Authors :
Takeshita، نويسنده , , Hiroki and Gao، نويسنده , , Yuan-Ji and Natsui، نويسنده , , Tomoyuki and Rodriguez، نويسنده , , Erick and Miya، نويسنده , , Masamitsu and Takenaka، نويسنده , , Katsuhiko and Shiomi، نويسنده , , Tomoo، نويسنده ,
Issue Information :
دوهفته نامه با شماره پیاپی سال 2007
Pages :
12
From page :
7660
To page :
7671
Abstract :
The microphase separation structure in the molten state and the structure formation in crystallization from such ordered melt were investigated for the blends of polystyrene–polyethylene block copolymers (SE) with polystyrene homopolymer (PS) and polyethylene homopolymer (PE) and for the blends consisting of two kinds of SE with different copolymer compositions from each other, using synchrotron small-angle X-ray scattering techniques (SAXS). The copolymer compositions of SE block copolymers employed were 0.34, 0.58 and 0.73 wt. fraction of PE, and their melt morphologies were cylindrical, lamellar and lamellar, respectively. Macrophase separation or the morphology change in the melt occurred depending on the molecular weight and the blend composition, as reported so far. In crystallization from such macrophase-separated and microphase-separated melts, the melt morphology was completely kept for all the blends. Crystallization behavior was also investigated for the blends. The crystallization within the spherical and cylindrical domains surrounded by glassy PS was not observed for SE/PS blends. In the crystallization from the macrophase-separated melt, two exothermal peaks were observed in the DSC measurements, while a single peak was observed for other blends. For the blends with PS, the degree of crystallinity was depressed and the apparent activation energy of crystallization was high, compared to those for the corresponding neat SE. For SE/PE and SE/SE blends, those were changed depending on the blend composition.
Keywords :
Microphase separation , Polystyrene–polyethylene block copolymer , crystallization
Journal title :
Polymer
Serial Year :
2007
Journal title :
Polymer
Record number :
1731150
Link To Document :
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