$(10pts)$ O$-$rings made of the semicrystalline polymer Delrin ${?}^{TM}($polyoxymethylene$)$ are in hydraulic pumps and other systems which results in their exposure to hydraulic fluids and water. A comparison of injection molded o$-$rings, IM to those that had been compression molded, CM$,$ showed that the IM o$-$rings exhibited much more significant swelling, loss of dimensional tolerance and wear. $($a$)$ Explain these differences in terms if the morphology of the IM vs$.$ CM o$-$rings.

b$.)$ How do you think adding a small percentage $($eg$.,2wt\%)$ of layered silicate nanoparticles to the polymer would affect the swelling, dimensional stability and wear properties?

c$.)$ How do you characterize the dispersion of nanosilicates and worphologies in polymer$-$clay nanocomposites