Segmental dynamics of polyurea: Effect of stoichiometry

Segmental dynamics of polyurea: Effect of stoichiometry

We study the effect of variations in the soft/hard segment ratio, achieved through stoichiometry changes, in elastomeric polyurea. These variations have a marked effect on the mechanical properties; however, the materials exhibit very similar glass transitions and local segmental relaxation dynamics...

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Bibliographic Details
Published in:Polymer (Guilford) Vol. 51; no. 1; pp. 178 - 184
Main Authors: Fragiadakis, D., Gamache, R., Bogoslovov, R.B., Roland, C.M.
Format: Journal Article
Language:English
Published: Kidlington Elsevier Ltd 06-01-2010
Elsevier
Subjects:
Applied sciences
Ballistic coatings
Exact sciences and technology
Organic polymers
Physicochemistry of polymers
Polyurea
Properties and characterization
Rheology and viscoelasticity
Segmental dynamics
Polyurea
Ballistic coatings
Segmental dynamics
Stoichiometry
Amino group
Telechelic polymer
Mechanical properties
Urea polymer
Thermoplastic rubber
Experimental study
Segmental movement
Property processing relationship
Molecular relaxation
Polyaddition
Dielectric relaxation
Organic diisocyanate
Butene oxide polymer
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Summary:We study the effect of variations in the soft/hard segment ratio, achieved through stoichiometry changes, in elastomeric polyurea. These variations have a marked effect on the mechanical properties; however, the materials exhibit very similar glass transitions and local segmental relaxation dynamics. The latter differ only at elevated pressure, an increase in hard segment content associated with greater sensitivity to pressure and volume changes. In this respect the polyurea mimics the behavior found recently for an elastomer reinforced with hard filler particles. The resistance to ballistic penetration of the polyurea was unaffected by the stoichiometry variations, consistent with the idea that the impact performance of elastomers is governed by the segmental dynamics rather than properties measured in conventional mechanical tests. [Display omitted]
ISSN:0032-3861
1873-2291
DOI:10.1016/j.polymer.2009.11.028