1.) How are these plastics being developed?
Green plastics are developed with natural sugar - cane, beet, and corn. Factories turn the sugar into polylactic acid, which they can then convert to plastic. Regular plastics are made of small molecules called monomers, which, when connected together through polymerization, turn into one big polymer which is similar to one long chain.. The type of polymerization used to make plastic is called a condensation reaction, which means that a small molecule such as water, is released every time two monomers are connected.
2.) What makes these plastics "green"?
These plastics are "green", because they are made out of beet, corn, and cane sugar - renewable resources. This makes bio plastics more eco-friendly. Lactic acid is an example of a bio plastic. The thing about lactic acid is that it is only a building block for plastic, because it can't be converted into plastic directly. This because the chemical reaction that takes place when lactic acid is made produces water. This water prevents the lactic acid from becoming one long chain like the monomers in regular plastic. Instead, the lactic acid molecules create a whole bunch of smaller chains. These are combined in a chemical reaction to make lactide, which then makes monomers that can then be created into polylactic acid.
3.) What are some of the issues with plastics that were mentioned?
There are a couple different issues with bio plastic that are bad for the environment. One is the fact that growing all those crops to produce the sugar to produce the acid, to produce the plastic takes extra space. We already use a lot of land to grow produce and livestock. When we do this, we clear away land, cut down trees, and ruin animal habitats. Sugar crops take up a lot of space which leads to less forests. Also, there is a limited amount of space where we can grow food. If we grow too many food crops that aren't for food purposes, we might face a food crisis.
Another "con" about bio plastic is that it takes the exact same amount of resources to create it as regular plastic. If you add up all the pesticides and herbicides that pollute water, as well as the oil used in farming and shipping the crops, plus the energy we need to create the lactic acid and turn it into plastic, we get a pretty big sum of resources.
One last example of why bio plastic isn't great is because we can't recycle it with other plastics. Since bio plastic breaks down into a completely different substance then our average pet bottle, they can't be mashed down and recycled - we would need a completely new recycling system. Scientists are afraid that if we use too much bio plastic and don't recycle it, it will end up in a land fill. It is predicted that if we leave bio plastic to biodegrade by itself, it will produce methane gas, which is another greenhouse gas, but worse than carbon dioxide. Too many greenhouse gasses will lead to a major climate change.
4.) How might these green plastics change packaging practices?
These green plastics might change the packaging practices by making them less recyclable. If we make pet bottles out of bio plastic, we wouldn't be able to recycle them, and they will probably produce more carbon dioxide and methane while biodegrading, than they would if we had used regular plastic in the first place. We would have to devise a whole new recycling system, plus a new symbol for "green" plastics, and use up more crude oil to make extra garbage cans for the new plastic. Bio plastic might even use up more resources than if we stuck to regular plastic. Only time will tell for sure, but one thing is certain - bio plastic is a sign that we are trying to take a step in the right direction!
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