For the following pair of polymers, plot and label schematic stress$-$strain curves on the same graph. Please explain your graph.

Poly$($styrene$-$butadiene$)$ random copolymer having a number$-$average molecular weight of $110,000\frac{g}{m}ol$ and $15\%$ of the available sites crosslinked and tested at $25C$

Poly$($styrene$-$butadiene$)$ random copolymer having a number$-$average molecular weight of $130,000\frac{g}{m}ol$ and $25\%$ of the available sites crosslinked and tested at $-90C.$