Re: What is silly string made of?

This is a good question, one that I can't answer.  The can lists no 
ingredients and the manufacturer says this information is proprietary.
Sorry.

As for air dried polymers, maybe solvent casting is what you're after.  A 
fair number of polymers can be dissolved and then cast into a thin sheet.  
The problem is the solvents.  Some can get nasty.  But as a starting place, 
PVC can be dissolved in tetrahydrofuran and cyclohexanone.  Polystyrene 
dissolves in a number of alkanes- like gasoline.