Plastic toys with a McDonald’s, primarily for recycling (9)
I believe the answer is:
styrofoam
'plastic' is the definition.
(I know that Styrofoam is a type of foamed polystyrene)
'toys with a mcdonald's primarily for recycling' is the wordplay.
'with' says to put letters next to each other.
'mcdonald's' becomes 'M' (fast food franchise known for its yellow M logo).
'primarily' means one lot of letters go next to another.
'recycling' indicates anagramming the letters.
'a' put after 'm' is 'ma'.
'ma'+'for'='mafor'
'toys' put after 'mafor' is 'mafortoys'.
'mafortoys' with letters rearranged gives 'STYROFOAM'.
(Other definitions for styrofoam that I've seen before include "Light resilient plastic made of polystyrene" , "Synthetic material" .)