What is biopolypropylene?
Biopolypropylene is a thermoplastic polymer commonly used in the packaging industry. Other uses include textiles, bottles, Rubik’s cube stickers, and even polymer banknotes. Because polypropylene shares many properties with polyethylene, they are commonly employed for similar uses. Polypropylene is especially resistant to fatigue, which is ideal for mobile plastic parts. Conventional polypropylene is made from petroleum in a process which results in large amounts of green house gases. However, an alternative process has been developed which allows for its synthesis from sugar cane.
The feedstock for biopolypropylene is sugar cane. The use of sugar cane has extensive environmental benefits. By reducing petroleum use, environmental damage is minimized. Furthermore, sugar cane sequesters a large amount of CO2 during growth. By the time the biopolyethylene is produced, a net reduction of CO2 is achieved. Over 1.5 billion pounds of CO2 per year are consumed by the process. Additionally, the use of sugarcane rather than corn reduces pressure on the food supply.
Biopolypropylene chains have methyl groups which stick out from the back bone. They are usually isotactic, or on the same side and plane of the backbone, with properties similar to polyethylene. Biopolypropylene is tough and flexible, being able to withstand impacts well. This makes it ideal for packaging material.
How is biopolypropylene produced
In order to produce biopolypropylene, several routes can be followed. The use of sugar cane employs enzymatic fermentation to produce ethanol. The ethanol is then dehydrated to ethylene which is dimerized to produce n-butene. The n-butene is then reacted with the ethylene to produce biopolypropylene. A similar production route is possible using butanol from sugar cane fermentation. Efforts are currently underway to open a biopolypropylene plant using sugar cane from Brazil.