Dynamic Shear Modulus of Isotropic Elastomers

Autor:	Eugene M. Terentjev, and A. R. Tajbakhsh, Adam M. Squires
Rok vydání:	2004
Předmět:	Materials science Polymers and Plastics Organic Chemistry Isotropy Dynamic mechanical analysis Elastomer Inorganic Chemistry Shear modulus Superposition principle Rubber elasticity Dynamic modulus Materials Chemistry Composite material Glass transition
Zdroj:	Macromolecules. 37:1652-1659
ISSN:	1520-5835 0024-9297
DOI:	10.1021/ma035060e
Popis:	We have investigated the dynamic mechanical behavior of two cross-linked polymer networks with very different topologies: one made of backbones randomly linked along their length; the other with fixed-length strands uniformly cross-linked at their ends. The samples were analyzed using oscillatory shear, at very small strains corresponding to the linear regime. This was carried out at a range of frequencies, and at temperatures ranging from the glass plateau, through the glass transition, and well into the rubbery region. Through the glass transition, the data obeyed the time-temperature superposition principle, and could be analyzed using WLF treatment. At higher temperatures, in the rubbery region, the storage modulus was found to deviate from this, taking a value that is independent of frequency. This value increased linearly with temperature, as expected for the entropic rubber elasticity, but with a substantial negative offset inconsistent with straightforward enthalpic effects. Conversely, the loss modulus continued to follow time-temperature superposition, decreasing with increasing temperature, and showing a power-law dependence on frequency.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::f9203bc8e5de2a3906e51a17072385e4 https://doi.org/10.1021/ma035060e Zobrazit plný text záznamu