There is a method describedabout how to make bioplastic:

 

http://www.shapeways.com/blog/archives/374-Cooking-molding-bioplastics-at-home-recipes,-results-tips.html

 

I want to dry the resulting plastic just in anhour. How to do it?

 

 

Either heat it, or create a vacuum. It's the only way to remove moisture faster than just leaving it in the open air.

 

How fast it dries really depends on the shape of the plastic too. The bigger the surface area (compared to the volume), the faster it will dry.

 

Finally, if the air in which the plastic is placed (in the room, or a special box of some kind) is very dry, it will also speed up the drying.