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Linear and nonlinear viscoelasticity of oleogels based on vegetable oil and ethylene vinyl acetate copolymer/isotactic polypropylene blends
Author(s) -
Alfonso Jose Enrique Martín,
Valencia Concepción
Publication year - 2015
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.42477
Subject(s) - materials science , viscoelasticity , ethylene vinyl acetate , vinyl acetate , rheometry , composite material , copolymer , dissipation factor , rheology , tacticity , polypropylene , relaxation (psychology) , dynamic modulus , polymer chemistry , dynamic mechanical analysis , polymer , dielectric , polymerization , psychology , social psychology , optoelectronics
This work deals with a rheological study of oleogels based on high‐oleic sunflower oil (HOSO) and ethylene vinyl acetate copolymer (EVA) / isotactic polypropylene (iPP) blends. EVA copolymers with different vinyl acetate content were used. With this aim, linear small amplitude oscillatory shear (SAOS) and nonlinear (relaxation) measurements combined with polarized optical microscopy were carried out. Oleogels were prepared by using the mixing rheometry technique in a batch mixer. Oscillatory strain amplitude sweep tests showed that the end from the viscoelastic linear region for oleogels was accompanied by opposite trends for viscoelastic moduli. SAOS tests showed that all the oleogels present similar behavior characteristic of polymeric systems with physical entanglements. It was found that the elastic equilibrium modulus and loss tangent increases with iPP content. On the other hand, nonlinear relaxation tests presented a strong dependence on the strain applied and the Soskey–Winter model was found to provide an accurate description of the damping function of these oleogels. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42477.