11. Define the Hermann's orientation function, and explain how it can be determined experimentally. Derive its value for uniaxial, transverse, and random orientation 12. Outline some methods for obtaining ultra-high orientation in polymers (e.g. Kevlar, Spectra 13. Define the following elastic constants: Poisson's ratio, tensile odulus and compliance, and shear modulus and compliance. Give approximate values for the Poisson's ratio and tensile modulus of both glassy and rubbery polymers 14. Why does rubber have to be crosslinked to be useful (usually)? How is this de (show the chemistry) 15. Only cis-l, 4 polymerization of butadiene produces a good elastomer What are some other possibilit rubbers? How do we get the form we want? 16. Outline the concepts involved in the kinetic theory of rubber 17. Give the relation for strain energy in a rubber as a function of the extension ratios, and from this develop equations governing the extension ratio and the applied load for uniaxial tension, equal biaxial tension, and unequal biaxial tension 18. Develop an expression for the radius of a spherical rubber balloon function of the internal pressure 9. Consider two spherical rubber balloons, initially identical. One is inflated to n=2, the other to A =3. What happens when the balloons are connected at their necks so that air can flow from one to the other? (Just a qualitative description, based on the rubber elastic curve below11. Define the Hermann’s orientation function, and explain how it can be determined experimentally. Derive its value for uniaxial, transverse, and random orientation. 12. Outline some methods for obtaining ultra-high orientation in polymers (e.g. Kevlar, Spectra). 13. Define the following elastic constants: Poisson’s ratio, tensile modulus and compliance, and shear modulus and compliance. Give approximate values for the Poisson’s ratio and tensile modulus of both glassy and rubbery polymers. 14. Why does rubber have to be crosslinked to be useful (usually)? How is this done (show the chemistry). 15. Only cis-1,4 polymerization of butadiene produces a good elastomer. What are some other possibilities, and why do they not make good rubbers? How do we get the form we want? 16. Outline the concepts involved in the kinetic theory of rubber elasticity. 17. Give the relation for strain energy in a rubber as a function of the extension ratios, and from this develop equations governing the extension ratio and the applied load for uniaxial tension, equal biaxial tension, and unequal biaxial tension. 18. Develop an expression for the radius of a spherical rubber balloon as a function of the internal pressure. 19. Consider two spherical rubber balloons, initially identical. One is inflated to λr = 2, the other to λr = 3. What happens when the balloons are connected at their necks so that air can flow from one to the other? (Just a qualitative description, based on the “rubber elastic” curve below.)