The reason plastic is awesome is that it's super durable, so it lasts forever. The problem is that it lasts forever, even when we want it to just go away and take its place in the circle life. Biodegradable plastics aren't new, but in the past they've been pretty weak and expensive, so not optimal replacements for your grocery sack. Eco-geeks at the Missouri University of Science and Technology have come up with the anti-daywalker of plastic: All of its strengths, but it disintegrates in four months.
Basically they're making plastic cocktails, which vary depending on how the plastic's going to be used: a blend for water bottles, another for groceries, all using bio-based fillers in the polymers, so it'll be cheaper than past biogradegradables, but still fairly strong. One possible filler is glycerol, which is a waste product of making biodiesel. Another is polylactic acid, which is made by fermenting starches, and breaks down in just 60 days—it's a possible candidate for water bottle plastics.
Course, you could use a polycarbonate or steel bottle over and over again, and cloth grocery bags, and skip the plastic entirely, but someone's gotta take out those bastard sea gulls. [PhysOrg via PopSci via New Launches, Image via Flickr]