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Characterization of Morphologies of Compatibilized Polypropylene/Polystyrene Blends with Nanoparticles via Nonlinear Rheological Properties from FT-Rheology

Salehiyan, Reza; Yoo, Youngjae; Choi, Woo Jin; Hyun, Kyu


Reza Salehiyan

Youngjae Yoo

Woo Jin Choi

Kyu Hyun


Linear and nonlinear viscoelastic properties under dynamic oscillatory shear flow were used to investigate the effects of compatibilization on polypropylene (PP)/polystyrene (PS) blends. Two different nanoparticles (organo-modified clay and fumed silica) were used at various concentrations. To analyze nonlinear stress under large amplitude oscillatory shear (LAOS) flow, nonlinearity (I3/1) was calculated from FT-rheology. To quantify the degree of dispersion of different particles at various concentrations, a new parameter, nonlinear–linear viscoelastic ratio (NLR ≡ normalized nonlinear viscoelasticity/normalized linear viscoelasticity), was used. The relationship was determined between NLR value and PS droplet size in the PP matrix. From the TEM images, clay was located mostly at the interface or partially inside the PS drops, thereby reinforcing the compatibilization effect. Therefore, clay increased the dispersion morphologies of the PP/PS blends. In contrast, fumed silica was located mostly inside the PS droplets, which means the morphologies of PP/PS blends were not improved. Linear viscoelasticities of both PP/PS/clay and PP/PS/silica showed improvements at elevated particle concentrations. NLR values for the PP/PS/Clay blends were larger than 1 (NLR > 1), whereas NLR values for the PP/PS/silica blends were less than 1 (NLR < 1). Therefore, NLR could be classified into two categories depending on morphology. Based on these results, NLR can be used to distinguish between the effects of two different types of nanoparticles on the morphologies of PP/PS blends.

Journal Article Type Article
Online Publication Date Jun 13, 2014
Publication Date 2014-06
Deposit Date Jan 30, 2023
Journal Macromolecules
Print ISSN 0024-9297
Publisher American Chemical Society
Peer Reviewed Peer Reviewed
Volume 47
Issue 12
Pages 4066-4076