Entanglement Coupling in Linear Polymers Demonstrated by Networks Crosslinked in States of Strain
AUTOR(ES)
Kramer, Ole
RESUMO
Linear 1,2-polybutadiene is crosslinked at 0° by γ-irradiation while strained in simple extension, with extension ratios from 1.3 to 2.0. During irradiation times up to several hours, entanglement slippage is slight, since the temperature is only slightly above the glass transition. Subsequently, samples are released and reach their equilibrium states of ease at room temperature. From the extension ratio at state of ease, the ratio of νx (effective network strands terminated by crosslinks introduced) to νN (effective network strands terminated by entanglements) is calculated by composite network theories of Flory and others; and from the extension ratios together with the modulus, measured at small extensions, νN is calculated explicitly. It appears that νx increases approximately proportional to irradiation time; νN is approximately independent of irradiation, and it corresponds to a molecular weight between effective entanglement loci of about 13,000. This figure, however, which is larger than that deduced from rheological properties of the uncrosslinked polymer, is subject to future downward correction for partial entrapment of the entanglements and other refinements.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=426903Documentos Relacionados
- Sorption of 2-Chlorophenol from aqueous solutions by functionalized cross-linked polymers
- Structural and Viscoelastic Properties of Actin/Filamin Networks: Cross-Linked versus Bundled Networks
- Partitioning and diffusion of proteins and linear polymers in polyacrylamide gels.
- Effect of cross-linked biodegradable polymers on sustained release of sodium diclofenac-loaded microspheres
- Rapid formation of large molecular weight alpha-polymers in cross-linked fibrin induced by high factor XIII concentrations. Role of platelet factor XIII.
