Brainstorming art and life projects using special recycled materials..doing some research and comparisons.
Plastic Lumber(from their FAQ):
IS PLASTIC LUMBER ENVIRONMENTALLY SOUND?
YES. First, plastic lumber is made of 100% recycled plastic which would normally end up in landfills. Second, plastic lumber can't leech and contaminate the soil because it is non porous and contains none of the chemical hazards associated with pressure treated and creosoted lumber. Third, the manufacturing process is a clean, extrusion process. Fourth, plastic lumber saves trees and rain forests. Finally, plastic lumber is 100% recyclable.
Trex:
Trex decking is made from post-consumer and/or post-industrial reclaimed plastic and waste wood. The reclaimed plastic comes primarily from grocery sacks and stretch film, and the waste wood is from woodworking manufacturers.
Unlike plastic lumber, which is typically 100% plastic, Trex decking is approximately 50% wood fiber and 50% plastic. Because of the wood content, Trex has the advantages of low thermal expansion/contraction, natural UV stability, good traction and paintability, and Trex decking is just as easy to work with as wood.