Well, with Polymer engineering, and quite a lot of Materials engineering I'd imagine, you do need to know some basic chemistry to understand specific composition (especially if you have to figure out what the hell a material's made out of with reverse engineering), but that isn't so important as learning the physical characteristics of the materials and why they're that way. Like with polymers, you need to know the different types of fluids (non-Newtonian vs. Newtonian), how the length of polymer chains cause certain phenomenon (entanglement, extruder swell, etc.), the difference between Amorphous and Semicrystalline, and so on. So it's minimal memorization of basic facts (like with Biology), and mostly about understanding how the properties of a material effect things, and why the properties are what they are.
If you're interested in some of the things I do in my lab, most of the business we get is through people using our DSC (differential scanning calorimetry) and TGA (thermogravimetric analysis) machines to determine the properties of their samples. Wikipedia has articles that cover both of these pretty extensively.