Polycaprolactone

Polymorph is a non-toxic, biodegradable polyester with a low melting temperature of about 60°C (140°F). Prototype plastic parts can be made by simply heating the plastic beads in hot water ...

• http://www.sparkfun.com/products/10951
• http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Prototyping/Make_With_Polymorph.pdf