The vast ship of plastics commerce continues its turn toward sustainability a few degrees (minutes? seconds?) at a time. As designers we need to make certain that we are providing a helpful current by specifying the best available material options. Bayer's recently announced Polycarbonate/ABS blends with high recycled content are worth your consideration.
They have also announced two PC/PLA alloys. The structural characteristics of these two alloys compare very favorably with that of PET or SAN filled PC. The advantages of the PLA component lie in the reduction of energy and greehouse gas required to manufacture the resin and the reduction of the non-renewable content. It looks as if knit-lines may be an issue with these resins, so early consultation with a Bayer engineer would be important.