Polyetherketone $($PEK$)$ and poly$($ ether etherketone$)($PEEK$)$ are two engineering

polymers which are highly chemical resistant.

Which of the two has a higher glass transition temperature T g$\text{'}$ PEK or PEEK? Why

do you think that these materials are highly chemical resistant?

PEEK has aT g ; $144\backslash$deg C and a T m ; $335\backslash$deg C$,$ respectively. How does the mechanical behaviour $($e$.$g$.$ the E$-$modulus$)$ change between $25$ to $335\backslash$deg C$?$ Draw a stress$-$strain

curve of PEEK at $35\backslash$deg