广东费飘职业故本学院 Guangdong Inatitute of Textile Technology Fiber Properties and Identification a Stress-strain curves ■ Yield point a The polymers yield or molecular chains start to move and pass one another a The deformation is permanent a The slope of the stress-strain curve after yield point relies on the strength of intermolecular forces flax due to strong intermolecular forces a Most fibers have yield point but not cotton andFiber 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