I think the biggest material impact for any curb on plastics would largely be felt in medicine. Disposability is huge in preventing infection. Also, many medical implants rely on the combination of elasticity and strength found in plastics.
Obbiosl computing would be radically altered as well but I'm not actually sure how much that would matter. Other than during the 90s, there just simply isn't much evidence for all this extra computing having a significant effect on growth.