Briefly describe one application/materials system in which a high diffusion rate is desirable, and one application/materials system in which a high diffusion rate is undesirable. Note: Your answer should not be based on case hardening of steel and doping semiconductors are discussed in the lectures and textbook.

Plot schematically the tensile stress versus strain curves for a typical thermoplastic material at a temperature below its glass transition temperature (tg and at a temperature above its tg, respectively. do the same for a typical thermosetting material. list in a table any differences or similarities between the two materials at t> tg and t < tg, respectively, and relate them to the structures of the two types of polymers