Innovative plastics from South Dakota corn stalks

By Scout Nelson

At the Composites and Polymer Engineering (CAPE) lab at the South Dakota School of Mines and Technology (SDSMT) in Rapid City, researchers are advancing methods to convert agricultural byproducts like corn stalks into valuable materials, especially plastics. The process begins similarly to brew beer, starting with fermentation.

Led by Dr. David Salem, the CAPE lab focuses on polymers, polymer processing, and composites. This involves adding various substances to polymers to enhance their properties, such as strength.

Dr. Salem, a professor of materials and metallurgical engineering, views this research as the future of manufacturing. He highlights the advantage of being in South Dakota, where abundant corn and soybean production provides essential raw materials.

The lab's goal is to address the "scourge of biodegradability" by creating polymers that are not petroleum-based, break down easily, and are cost-effective. Corn-stover-based polymers developed at CAPE could potentially replace polyester and polyethylene. However, the exact properties of these polymers on a larger scale remain uncertain.

Scaling up production is a challenging task the lab is actively pursuing. Initially, CAPE could produce only 3 liters of polymer. Thanks to a recent grant, the lab can now produce up to 260 liters. This scale-up is crucial for assessing commercial viability and attracting industry interest.

CAPE collaborates with South Dakota State University Extension to source most of its corn stover. However, for larger production volumes, additional sources may be needed.

The polymers developed have diverse applications, from short-term use items like grocery bags and water bottles to high-value products such as helmets and protective vests.

Dr. Salem explains that the same chemical structure, polyethylene, used in everyday grocery bags, is also used in bulletproof vests. The difference lies in processing, where the arrangement and alignment of molecules determine the final product's properties. This innovative work at the CAPE lab signifies a promising future for sustainable materials derived from South Dakota-grown grains.

Photo Credit: south-dakota-state-university