Plate Nº 32 · recorded October 10, 2026
Chemistry & MaterialsReported finding
Hemp waste cellulose boosts biodegradable film strength by 26%
A KRICT-led Korean team raised the tensile strength of a biodegradable film by 26.2% using cellulose recovered from hemp hurd, the woody stalk core that makes up roughly 70% of each hemp plant.
By Marcus Bennett3 min read576 words
In brief
- Cellulose from hemp hurd improved a biodegradable TPS/PBAT film's tensile strength by 26.2%, versus 1.5% for conventionally dried cellulose.
- Water vapor transmission through the film dropped by roughly 17%, and oxygen transmission fell by about 9%.
- Hemp hurd accounts for about 70% of an industrial hemp stalk by weight and is largely a textile-industry waste stream.
- The fiber saturation point of hemp hurd-derived cellulose sits at roughly 30% moisture, the threshold that guided the team's drying protocol.
- The peer-reviewed paper appeared in the Chemical Engineering Journal in 2026, DOI 10.1016/j.cej.2026.179503.
A Korean research team raised the tensile strength of a biodegradable plastic film by 26.2% using cellulose recovered from discarded hemp stalks, according to a paper published in the Chemical Engineering Journal in 2026.
The work, led by Dr. Hoyong Kim at the Korea Research Institute of Chemical Technology (KRICT), targets a long-standing weak spot of compostable packaging: the films tear easily and absorb too much moisture.
How much stronger did the film get?
The team loaded hemp-derived microfibrillated cellulose at 10 weight percent into a blend of thermoplastic starch (TPS) and poly(butylene adipate-co-terephthalate) (PBAT). These two polymers form the basis of biodegradable packaging films and agricultural mulch films designed to break down in soil.
Cellulose dried the conventional way improved tensile strength by only 1.5%. The KRICT filler raised it by 26.2%. Water vapor passing through the film dropped by roughly 17%, and oxygen transmission fell by about 9%.
What was the source material?
The cellulose came from hemp hurd, the woody inner core of industrial hemp stalks. Hurd makes up about 70% of each stalk by weight. Outer fibers go to traditional hemp textile production; the hurd has had few commercial uses.
South Korea currently cultivates industrial hemp only in designated "Regulation-Free Special Zones," including Andong in Gyeongsangbuk-do. The hurd generated by textile processing is the waste stream the team tapped.
Why is hemp cellulose hard to use?
Cellulose microfibrils — fibers just nanometers across — serve as strong reinforcing fillers for plastics when dispersed evenly. Conventional drying ruins them.
As water leaves the fiber walls, adjacent microfibrils form strong hydrogen bonds and clump into dense aggregates that cannot be redispersed. Materials scientists call this hornification.
Clumped fibrils cannot spread through a polymer film, so mechanical stress concentrates in weak spots and the film tears.
What was the team's solution?
The KRICT researchers built a two-step strategy around ordinary oven drying, avoiding energy-intensive freeze-drying and spray-drying.
Each plant fiber carries a fiber saturation point (FSP) — roughly 30% moisture for hemp hurd — below which bound water begins leaving the cell walls and hornification accelerates. The team measured the FSP of their hemp-derived cellulose and milled the material while its moisture stayed above this threshold, finishing processing before aggregation could take hold.
They then treated the cellulose surface with alkyl ketene dimer (AKD), a low-cost chemical widely used in paper manufacturing. AKD's hydrophobic chains act as molecular spacers, blocking hydrogen bonds between neighboring microfibrils as drying proceeds.
Moisture control plus AKD coating preserved the fine fibrillar structure without expensive equipment.
Could the same approach work on other crops?
Cellulose-rich residues such as soybean stalks and rice straw face the same hornification problem, and the team plans to test the moisture-and-AKD strategy on them.
These byproducts exist in large volumes globally and currently have low-value uses. A simple, scalable drying route to cellulose fillers could route farm waste into stronger compostable packaging and mulch films, the researchers write, though commercial-scale testing is still ahead.
What are the limits of the study?
The team tested a single filler loading, a single TPS/PBAT ratio, and one drying protocol. Independent laboratories have not yet replicated the results.
Long-term composting behavior, soil-microbe breakdown rates, and the cost of AKD treatment at industrial scale remain open questions before packaging companies or mulch-film suppliers can adopt the technology.
via Phys.org Chemistry (Source)
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