Styrene/Isoprene Block

In this example, the relative styrene chain lengths in the diblock and triblock materials are the same and so the diblock will have a reduced molecular weight and therefore size in solution compared to the triblock.

Using high efficiency GPC columns, the two components can be resolved based on this size difference. Figure 1 shows a chromatogram of a commercial SI/SIS blended product. The SI and SIS components have been resolved allowing quantifi-cation to take place. In this case, the SI content is approxi-may 42%, typical of a material that finds application in reducing the modulus of polyolefins.