Title:
Stress softening of multigraft copolymers
Languages of Item:
English
Abstract:
The hysteresis behaviour of multigraft (MG) copolymers, with a polyisoprene backbone and polystyrene (PS) side chains, was investigated by applying a modified softening model proposed by Elías-Zúñiga, which uses an approach of Ogden and Roxburgh. The model was combined with the non-affine tube model of rubber elasticity of Kaliske and Heinrich. Four parameters are obtained: chemical and physical cross-link moduli (Gc, Ge), the number of statistical segments between two successive entanglements (ne/Te) and a softening parameter (b). The model was proven to be valid by a comparison with other methods evaluating hysteresis behaviour. The characterization of the multigraft copolymers revealed a branch point and molecular architecture dependence of the softening parameter. b was low for tetrafunctional MG copolymers with cylindrical microdomains, and it was further reduced for a spherical morphology and for more complex molecular architectures. The magnitude of b also depends on the PS arm molecular weight for hexa- and tetrafunctional multigraft copolymers. © 2009 Elsevier Ltd. All rights reserved.
Authors:
R. Schlegel
D. Wilkin
Y. Duan
R. Weidisch
G. Heinrich
D. Uhrig
J.W. Mays
H. Iatrou
N. Hadjichristidis
Keywords:
Hysteresis, Hysteresis behaviour; Micro-domains; Molecular architecture; Multigraft copolymers; Physical cross-links; Rubber elasticity; Spherical morphologies; Stress softening, Architecture, elasticity; graft copolymer; natural polyisoprene; polystyrene; stress; synthetic rubber
Main subject category:
Science
Official URL (Publisher):
DOI:
10.1016/j.polymer.2009.10.026
