Summary of chemical structure and uses of several broad classes of commonly encountered polymers.  Including polyolefins like LDPE, HDPE, and PP; aromatic-containing polymers like polycarbonate, PET, and polystyrene; halogen-containing polymers like PVC and PTFE; and several other common engineering polymers like nylon or PMMA, or 3D printing polymers like PLA.
Doesn't attempt to include crystallinity or chain lengths, just the monomer units.  Includes the six listed Resin Identification Codes (RIC); everything shown without a recycle symbol may still be recyclable under RIC code 7 ("other").
Structure pictures collected primarily from wikipedia, and reworked for clarity and uniformity. 

(Corrections are welcome, my degrees are in math and computer science!)
Own work
Orion Lawlor