scholarly journals Coupling Kinetic Modelling with SAOS and LAOS Rheology of Poly(n‐Butyl Acrylate)

2021 ◽  
pp. 2100620
Author(s):  
Hannah Grotian genannt Klages ◽  
Nihal Ermis ◽  
Gerrit Albert Luinstra ◽  
Kristina Maria Zentel
Author(s):  
Gudrun A. Hutchins

In order to optimize the toughening effect of elastomers in engineering polymers, it is necessary to characterize the size, morphology and dispersion of the specific elastomer within the polymer matrix. For unsaturated elastomers such as butadiene or isoprene, staining with osmium tetroxide is a well established procedure. The residual carbon-carbon double bond in these materials is the reactive site and forms a 1,2-dilato complex with the OsO4. Incorporation of osmium tetroxide into the elastomer not only produces sufficient contrast for TEM, but also crosslinks the elastomer sufficiently so that ultramicrotomy can be accomplished at room temperature with minimal distortion.Blends containing saturated elastomers such as butyl acrylate (BA) and ethylene propylene diene monomer (EPDM) cannot be stained directly with OsO4 because effective reaction sites such as C=C or -NH2 are not available in sufficient number. If additional reaction sites can be introduced selectively into the elastomer by a chemical reaction or the absorption of a solvent, a modified, two-step osmium staining procedure is possible.


Author(s):  
E. Sekman ◽  
G. Varank ◽  
A. Demir ◽  
S. Top ◽  
M. S. Bilgili

2009 ◽  
Vol 46 (2) ◽  
pp. 85-91
Author(s):  
K. A. Selim ◽  
F. H. Abd El-Rahiem ◽  
A. A. El-Midany
Keyword(s):  

1993 ◽  
Vol 58 (10) ◽  
pp. 2349-2361 ◽  
Author(s):  
Jaromír Jakeš

Kinetic modelling of the molecular weight distribution (MWD) of polymer obtained by an anionic polymerization with two types of growth centres in a dynamic equilibrium, having different growth rates and lifetimes comparable to the polymerization time, was made for low monomer conversions. On the basis of distribution of the growth centres according to the total time spent in the fast growth state, it was shown that MWD of the resulting polymer are mostly bimodal at the beginning of the polymerization and change to unimodal MWD at sufficiently high polymerization degrees depending on the equilibrization rate. When all centres are in the fast state in the beginning, MWD are essentially unimodal throughout. A hint of trimodality is observed in some cases, in an extent hardly detectable in real chromatograms. Hence, a polymodal MWD can be explained only when more than two growth centres with different growth rates are assumed.


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