Why Do Polystyrene, d-Limonene, and Isobutane Not Form a Homogeneous Mixture?

[PRIDES]

Ok, I am really close to this.
d-Limonene dissolves Polystyrene (I have tested this)
and Liquid Isobutane mixes with d-Limonene (I have also tested this)
However, when I mix all three together, the Polystyrene becomes completely separated from the solution.
Same thing with all polymer solutions I try to mix with Isobutane, the polymer ceases to be dissolved.
Is this simply a matter of proportions, or is there something more I need to notice?
Preferably I just need some kind of polymer that is soluble in liquid isobutane, but I don't think that exists.
Is there some kind of mixture that will stay homogenous that consists of isobutane, a solvent, and a polymer?

 

[Bystander]

You have just met the incompatible molecular size/weight/dimension problem compounded by small vdW/Heitler-London/dispersion forces between molecules.