Strain crystallization

Strain crystallization is a phenomenon in which an initially amorphous solid material undergoes a phase transformation due to the application of strain. Strain crystallization occurs in natural rubber and some other elastomers. The phenomenon has important effects on strength and fatigue properties. There are various techniques for measuring crystallization in rubber, including: x-ray diffraction, specific heat changes, and density changes. Crystallization can also be observed indirectly through its effects on stress–strain and fatigue behavior.

Elastomers that strain crystallize

• Natural rubber (polyisoprene)
• Polychloroprene

Elastomers that do not strain crystallize

• Polybutadiene
• Styrene-butadiene

Sources

• Chapter 1, Engineering with Rubber, Ed. A. N. Gent, Hanser, 1992. ISBN 3-446-17010-3.
• B. Huneau, STRAIN-INDUCED CRYSTALLIZATION OF NATURAL RUBBER: A REVIEW OF X-RAY DIFFRACTION INVESTIGATIONS, Rubber Chem. Technol. 84, 425 (2011); doi:10.5254/1.3601131
• Mars, W. V. (2009). Computed dependence of rubber's fatigue behavior on strain crystallization. Rubber Chemistry and Technology, 82(1), 51–61.
• Chapter 10 – Strength of Elastomers, A.N. Gent, W.V. Mars, In: James E. Mark, Burak Erman and Mike Roland, Editor(s), The Science and Technology of Rubber (Fourth Edition), Academic Press, Boston, 2013, Pages 473–516, ISBN 9780123945846, 10.1016/B978-0-12-394584-6.00010-8

See also

• Crystallization of polymers