It is becoming increasingly clear that both divesting from fossil fuels and avoiding the build-up of plastic in the environment are essential to meeting the challenges of climate change. To this end, significant efforts are being made to develop degradable or recyclable polymers made from non-edible plant material, referred to as “lignocellulosic biomass”.
Producing competitive biomass-based plastics has not been easy. Conventional plastics are widespread because they combine low cost, heat stability, mechanical strength, processability and compatibility – properties that alternative plastic replacements must match or exceed.
Now a group of scientists, led by Professor Jeremy Luterbacher from EPFL's School of Basic Sciences, have successfully developed a biomass-derived plastic, similar to PET, that meets the criteria for replacing several current plastics while being more environmentally friendly.
Luterbacher said: “We essentially just 'cook' wood or other inedible plant material, such as agricultural waste, in cheap chemicals to produce the plastic precursor in one step. By keeping the sugar structure intact within the molecular structure of the plastic, the chemistry is much simpler than current alternatives.”
The technique is based on a discovery that Mr. Luterbacher and his colleagues published in 2016, where adding an aldehyde can stabilize certain fractions of plant material and prevent their destruction during extraction. By repurposing this chemistry, the researchers were able to rebuild a new useful bio-based chemical as a plastic precursor.
Lorenz Manker, the first author of the study, said: “By using another aldehyde glyoxylic acid instead of formaldehyde, we can easily cut 'sticky' groups on both sides of the sugar molecules, allowing them to act as plastic building blocks. This simple technique allows us to convert up to 25 percent of the weight of agricultural waste, or 95 percent of purified sugar, into plastic.”
The well-rounded properties of these plastics allow them to be used in applications ranging from packaging and textiles to medicine and electronics. The researchers have already created packaging films, fibers that can be spun into clothing or other textiles, and filaments for 3D printing.
Luterbacher said: “The plastic has very good properties, especially for applications such as food packaging. And what makes the plastic unique is the presence of the intact sugar structure. This makes it incredibly easy to make because you don't have to change what nature gives you, and easy to degrade because it can go back to a molecule that is already abundant in nature.”
Source: bioenergy-news.com
