Dynamic viscoelastic properties of poly(ethylene-propylene) diblock copolymer in the melt state and solutions

• Published in: Polymer (Guilford) Vol. 37; no. 23; pp. 5159 - 5163
• Main Authors: Sakurai, Kazuo, MacKnight, William J., Lohse, David J., Schulz, Donald N., Sissano, Joseph A., Wedler, Wolfgang, Henning Winter, H.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.11.1996; Elsevier
• Subjects: Applied sciences; dynamic mechanical; Exact sciences and technology; melt; Organic polymers; Physicochemistry of polymers; poly(ethylene-propylene)diblock copolymer; Properties and characterization; Rheology and viscoelasticity; poly(ethylene-propylene)diblock copolymer; dynamic mechanical; melt; Propylene copolymer; Molten state; Diblock copolymer; Ethylene copolymer; Mechanical loss; Experimental study; Dynamic elastic modulus; Frequency effect; Rheological properties; Concentrated solution
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/0032-3861(96)00297-2

Dynamic mechanical properties of a symmetrical poly(ethylene-propylene) diblock copolymer with a molecular weight of 99 × 10 3 were investigated in the melt state, as well as in solutions in 1,2,4-trichlorobenzene. In the melt state, the frequency dependence of the elastic and loss moduli ( G′ and G″, respectively) exhibited a limiting behaviour of G′ ≈ G″ ≈ ω 0.5 in the terminal zone, a marker of inhomogeneity. Even solutions of 15 vol% polymer showed such inhomogeneity. These rheological data indicate that the diblock polymer is microphase separated and the phases are strongly segregated. The limiting behaviour in the terminal zone suggests that a lamellar structure is present in the melt.