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Elongational viscosity for miscible and immiscible polymer blends. II. Blends with a small amount of UHMW polymer

โœ Scribed by Tatsuhiro Takahashi; Jun-Ichi Takimoto; Kiyohito Koyama


Publisher
John Wiley and Sons
Year
1999
Tongue
English
Weight
237 KB
Volume
72
Category
Article
ISSN
0021-8995

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โœฆ Synopsis


The effect of miscibility on elongational viscosity of polymer blends was investigated in homogeneous, miscible, and immiscible states by the blend of 1.5 wt % of ultrahigh-molecular-weight (UHMW) polymer. The matrix polymer was either poly-(methyl methacrylate) (PMMA), or poly(acrylonitrile-co-styrene) (AS) that has a comparable elongational viscosity value. The homogeneous blend consisted of 98.5 wt % of PMMA and 1.5 wt % of UHMW-PMMA. The miscible blend was composed of AS and UHMW-PMMA at the same ratio. The immiscible blend was a combination of AS and UHMW-polystyrene (PS) at the same ratio. The strain-hardening behavior of the different blends were compared with that of pure PMMA. It was demonstrated that 1.5 wt % of UHMW induces a strong strain-hardening property in the homogeneous and miscible blends but was hardly changed in the immiscible blend. The optical microscope observation of the immiscible blend suggested that the UHMW domains were stretched, but that the degree of domain deformation was less than a given elongational strain. It was concluded that the strain-hardening property is strongly affected by the miscibility of UHMW chain and matrix. The strong strain-hardening property is caused by the deformation of the UHMW polymer. UHMW chains are stretched when they are entangled with surrounding polymers. However, UHMW chains in an immiscible state are not so deformed because of viscosity difference and no entanglements between domain and matrix. A smaller degree of UHMW chain deformation in immiscible state results in weaker strain-hardening property.


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Elongational viscosity for miscible and
โœ Tatsuhiro Takahashi; Jun-Ichi Takimoto; Kiyohito Koyama ๐Ÿ“‚ Article ๐Ÿ“… 1999 ๐Ÿ› John Wiley and Sons ๐ŸŒ English โš– 395 KB ๐Ÿ‘ 1 views

The effects of miscibility and blend ratio on uniaxial elongational viscosity of polymer blends were studied by preparing miscible and immiscible samples at the same composition by using poly(methyl methacrylate) (PMMA) and poly(acrylonitrileco-styrene) (AS). Miscible polymer blend samples for the e