Study: Hemp Hurd Can Be Used to Strengthen Biodegradable Plastic 

Researchers in South Korea say they developed a method to strengthen biodegradable plastic using hemp hurd, an agricultural byproduct, by extracting cellulose from discarded stalks of industrial hemp used in the production of traditional hemp textiles.

The study from the Korea Research Institute of Chemical Technology (KRICT) applied a drying process that preserves the microfibrillar structure of the cellulose, which enabled it to serve as a reinforcing biofiller for biodegradable plastics.

In South Korea, industrial hemp is cultivated in designated Regulation-Free Special Zones, including Andong, Gyeongsangbuk-do. The outer part of the stalk is used to obtain fibers, while the remaining woody core, known as hemp hurd, accounts for roughly 70% of the stalk by weight and has had relatively limited applications.

The team incorporated hemp-hurd-derived cellulose at 10 weight percent into biodegradable plastic film and found it improved tensile strength by 26.2%, compared with cellulose microfibrils prepared by conventional drying, which improved tensile strength by 1.5%. The hemp hurd cellulose also improved moisture and oxygen barrier performance by 17% and 9%, respectively, compared to the conventional method.   

The technology could be extended to various other cellulose-rich agricultural residues, including soybean stalks and rice straw, the researchers noted, adding plans for further study.

The study, “Fiber-saturation-point-guided microfibrillation of hemp hurd enabling concurrent performance enhancement of thermoplastic starch/polybutylene adipate terephthalate,” was pre-published in the Chemical Engineering Journal.