Hello Vignesh,

For your reactions the best green solvent is alcohol.

Polyurethane is made by reacting isocyanate in polyol (you can use erythritol or glycerol which are green to synthesise the polyurethane). 

Hope that helps. 

Thank you Mr.Vidhura Mahendra sir

You may try tallowates (tallic oil acids) and neutralize with a "green" amine

Thank you  gerhard sir

Pus are not soluble in any alcohols or polyols. Of course the PUs are made by the reaction between polyols and isocyanates. The best solvents which dissolve PUs are ketonic solvents and  esters For example MEK or ethyl acetate etc

Thank you Mr.Nori krishnamurti