Fiber Properties and ldentification Stress-strain curves Yield point The polymers yield or molecular chains start to move and pass one another The deformation is permanent The slope of the stress-strain curve after yield point relies on the strength of intermolecular forces Most fibers have yield point but not cotton and flax due to strong intermolecular forcesFiber Properties and Identification • Stress-strain curves – Yield point • The polymers “yield” or molecular chains start to move and pass one another. • The deformation is permanent. • The slope of the stress-strain curve after yield point relies on the strength of intermolecular forces. • Most fibers have yield point but not cotton and flax due to strong intermolecular forces