In what could be a breakthrough in the battle to tackle the threat that plastic poses to the environment, scientists have come up with plant oil plastic, an eco-friendly alternative that can be recycled at least 10 times.
Chemical material scientist Stefan Mecking of the German University of Konstanz has developed this plant oil plastic that has been engineered on the molecular level that allows an ease of processing.
Published in Nature, the find is even more significant as the raw materials used in plant oil plastic make it an environmentally safer alternative to the fossil-based variety.
Plastic recycling follows a mechanical routine where the waste particles are segregated, broken up, and transformed into little pellets that are then processed to make new plastic articles.
But researchers are hopeful of a new technique of recycling involving chemicals. This breaks down the long chain that comprises plastic polymers using solvents to revert to the monomer compounds of the initial material.
But the strong carbon bonds of the molecular structure of plastic make it a challenging process. It requires extreme temperatures to break these molecular bonds. For example, polyethylene requires 600C to turn it into monomers that are then recycled chemically at rates below 10%.
Plant Oil Plastic Bonds Break Easily
But the chemical bonds of the plant oil plastic that the researchers developed break more easily. Two variants of polycarbonate and polyester were immersed in methanol or ethanol in the absence of a catalyst at 150C. they also placed it at 120C with a catalyst.
In the case of polycarbonate, the researchers could recover 96% of the original material after the recrystallized plastic was cooled down and filtered. They further discovered that recycling worked even when there were fillers or plastic dye present.
Even the presence of other forms of plastic in the plant oil plastic solvent did not hinder the recovery process.
Plant oil was chosen for plastic synthesis as they have long chains. Further, they have a sustainable source of supply than fossil fuels such as crude oil.
Plant oil plastic has a density comparable to polyethylene. It also has a similar structure, elasticity, molecular weight. But the crystallization points and melting points for polyester and polycarbonate are lower. Plant oil plastics also degrade faster due to their changed breakpoints.
Pricing remains the only hurdle as ethylene remains the cheaper option so switching over to plant oil plastics will remain a challenge till that is resolved.
All image credits: Stephen Mecking