Korean researchers have discovered a way to strengthen biodegradable plastics by using hemp hurd, which is the woody core of the hemp plant. This part of the plant, often discarded after the outer fibers are extracted for textiles, makes up about 70% of the hemp stalk by weight and has not been widely used in industry. The research, led by Dr. Hoyong Kim at the Korea Research Institute of Chemical Technology (KRICT), involves extracting cellulose from hemp hurd and using a specialized drying process to preserve its microfibrillar structure. This structure is then used as a reinforcing material in biodegradable plastics. The findings were published in the Chemical Engineering Journal. Biodegradable plastics made from materials like thermoplastic starch (TPS) and poly(butylene adipate-co-terephthalate) (PBAT) are gaining interest for use in eco-friendly packaging and agricultural films. These materials can break down in soil, reducing environmental impact. However, they are often weak and prone to tearing, especially when exposed to moisture. While cellulose from sources like cotton or wood pulp can be used to reinforce such plastics, the process of turning it into microfibrils is expensive and complex. Hemp, which is grown in designated areas in South Korea, offers a promising alternative as it produces large quantities of this type of material as a byproduct. A major issue in creating strong biodegradable plastics is that cellulose microfibrils tend to clump together when dried using traditional methods. This clumping, known as hornification, reduces the effectiveness of the material in strengthening the plastic. For the plastic to be strong, the microfibrils need to be evenly spread throughout the material so that they can distribute stress properly. Conventional drying methods are not ideal for this, and alternatives like freeze-drying are too costly for mass production. The KRICT team developed a new, cost-effective method to prevent this clumping without using expensive equipment. The researchers used a two-step process that involved carefully controlling the moisture content of the hemp-derived cellulose and treating its surface with a low-cost chemical called alkyl ketene dimer (AKD). By maintaining the right level of moisture and applying AKD, they were able to preserve the delicate microfibrillar structure of the cellulose using standard oven drying. This method prevented the fibers from clumping together and allowed them to be evenly distributed in the biodegradable plastic. When tested, the resulting plastic showed a significant improvement in strength—26.2% higher tensile strength—compared to traditional methods. It also performed better in resisting water vapor and oxygen, making it more durable. The team believes this approach could be applied to other agricultural byproducts like soybean stalks and rice straw, offering a more sustainable solution for biodegradable materials.