Given the following data for characterization of a polymer w

Given the following data for characterization of a polymer, what is degree of polymerization based on weight average molecular weight? A stress of 2500 psi is applied to a polymer serving as a fastener in a complex assembly. At a constant strain, the stress drops to 2400 psi after 100 h. If the stress on the part must remain above 2100 psi in order for the part to function property, determine the life of the assembly. 527 h 427h 325 h 250h For a fixed time to rupture for polyethylene, applied stress can be at higher Lower - Temperature Higher - Temperature The same - Temperature Lower -Pressure Which one of the following statements is correct? Elastomers can sustain deformations greater than 200% Thermosets are formed in three-dimensional network structures Thermoplastics can be amorphous or crystalline All of the above.

Solution

7(a)degree of plymerization=9285/53=175.188

8.(c) In order to have material in safe mode. the value should not exceed 400 hours, so 325 hours which is less than 400 hours is an appropriate answer. 427 can\'t be accepted because it is more than 400 hours(it will fail)

10(B) Thermosets are stronger in nature.