Mixing Leftover Hemp from Hemp Cloth into Film... Biodegradable Plastic's Remarkable Strength Boost [Reading Science]

Korea Research Institute of Chemical Technology Develops Low-Cost Drying Technique to Prevent Clumping of Cellulose Microfibers

Potential for Use With Agricultural By-products Such as Soybean Stems and Rice Straw

Expected Application to Biod

Hemp stalks, which were previously discarded after being used for making hemp cloth, have been transformed into reinforcing materials that enhance the strength of biodegradable plastics. A team of Korean researchers has developed a technique that prevents the agglomeration of microfibers extracted from hemp through simple moisture adjustment and surface treatment—eliminating the need for costly freeze-drying. This new technology increases the strength of biodegradable plastics by more than 26%.

The Korea Research Institute of Chemical Technology (KRICT) announced on the 13th that a research team led by Principal Researcher Hoyong Kim has developed a technology to extract cellulose from the pith of industrial hemp stalks and utilize it as a reinforcing material for biodegradable plastics.

Manufacturing high-strength biodegradable plastics using hemp stalk microfibers. Provided by the research team

Industrial hemp is typically used for its bark as a raw material for fiber products such as hemp cloth. However, the pith, which accounts for about 70% of the stalk’s weight, has seen little practical use. The research team extracted cellulose microfibers from this pith and utilized them as reinforcement in films composed of thermoplastic starch (TPS) and biodegradable plastic PBAT.

The main issue was that during the drying process, cellulose microfibers tended to clump together. For the reinforcing effect to be maximized, the fibers must be evenly dispersed throughout the film, but if they aggregate, this effect diminishes. While freeze-drying or spray-drying can prevent this, these methods entail high energy and equipment costs, making them unsuitable for mass production.

Preventing Aggregation Through Moisture Control Instead of Costly Freeze-Drying

The research team developed a technique to maintain the microfiber structure during conventional heat drying by adjusting moisture content and treating the fiber surfaces with alkyl ketene dimer (AKD).

Cellulose fibers adhere strongly to one another when the moisture content drops below a certain level, as even internal water is lost. The team determined the so-called "fiber saturation point" for hemp fibers and processed them before the moisture content fell below this threshold. Surface treatment was additionally applied to further inhibit fiber-to-fiber adhesion.

Research team at the Korea Research Institute of Chemical Technology. (From left) Senior Researcher Junho Choi, Postdoctoral Researcher Haemin Cho, Postdoctoral Researcher Jonghwa Kim, Principal Researcher Hoyong Kim. Courtesy of KRICT

When 10% of this processed hemp cellulose was added to a starch-PBAT film, the tensile strength of the film increased by 26.2%. In contrast, films reinforced with microfibers dried using conventional methods showed only a 1.5% improvement. In addition, water vapor and oxygen permeability decreased by 17% and 9%, respectively, indicating enhanced barrier properties.

The research team expects that this technology can also be applied to cellulose extracted from other agricultural byproducts such as soybean stems and rice straw, and plans to conduct further research in this direction.

Dr. Kim stated, "This is an achievement in adding high value to agricultural byproducts." The research findings were published in the international journal 'Chemical Engineering Journal' in July 2026.

This content was produced with the assistance of AI translation services.