Hemp waste could become a valuable feedstock for lower-carbon packaging films, according to research exploring hemp hurd-based biocomposites as an alternative to fossil-based plastics. The study shows how a part of the hemp plant that is often discarded can be transformed into microfibres and blended with biopolymers to improve material performance for packaging and agricultural film applications.

Hemp hurd is the woody inner part of the hemp stem. It is typically less commercially valued than hemp fibre, but it offers an interesting opportunity for packaging because it is plant-based, widely available where hemp is processed and suitable for conversion into reinforcing microfibres. Turning this biomass residue into packaging material could support both resource efficiency and waste valorisation.

The researchers produced hemp hurd microfibres using dry and wet milling followed by micro-fibrillation. These microfibres were then used in two prototype material systems: packaging films blended with polylactic acid, known as PLA, and mulch films blended with starch-based thermoplastic, known as TPS, and poly(butylene adipate-co-terephthalate), known as PBAT.

Plant-based packaging materials will only scale if they combine renewable feedstocks with performance, processability and credible end-of-life pathways.

The addition of hemp microfibre improved mechanical performance. Tensile strength increased by approximately 20% for the packaging films and 33% for the mulch films compared with reference materials. This is important because many bioplastic alternatives must overcome concerns about strength, flexibility and reliability before they can compete with conventional petroleum-based films.

The research also highlights that the environmental impact of biocomposites depends strongly on how they are manufactured. Increasing the share of hemp microfibre and incorporating more biopolyesters could improve carbon savings. In optimised formulations, the study suggests reductions of up to 4.25 kg of CO2 per 1 kg of mulch film.

• Hemp hurd gives value to a biomass stream that is often underused.
• Microfibre reinforcement can improve tensile strength in bioplastic films.
• PLA-based films may offer potential for packaging applications.
• End-of-life choices strongly influence the overall carbon profile.

Processing choices were shown to matter. During microfibre drying, oven drying performed better from a sustainability perspective than spray drying. The study linked this difference to the higher electricity demand and coal combustion associated with spray drying. This finding is relevant for packaging developers because a renewable material does not automatically guarantee a low environmental footprint if processing is energy-intensive.

The researchers also conducted a life cycle assessment covering several end-of-life scenarios, including incineration with power recovery, incineration without power recovery, industrial composting and anaerobic digestion, using landfill as the reference case. Anaerobic digestion delivered the lowest global warming potential because biogas could be converted into electricity and the remaining digestate could be used as a soil conditioner.

For packaging films, the results point to a wider opportunity: agricultural residues can help reduce dependence on fossil-based materials when they are combined with appropriate biopolymers and responsible disposal systems. However, commercial adoption will require more than laboratory performance. Materials must meet requirements for film blowing or casting, sealing, barrier properties, shelf life, regulatory compliance and cost.

Hemp hurd-based biocomposites may be especially relevant for applications where flexibility, renewability and lower carbon impact are important. In food and pharmaceutical packaging, additional validation would be needed to confirm safety, migration performance and product compatibility. Still, the research adds to the growing interest in biobased materials that can serve packaging without relying solely on virgin fossil inputs.

The main lesson is that sustainable packaging innovation must be evaluated across the full life cycle. Feedstock origin, processing energy, mechanical performance and end-of-life infrastructure all affect the final environmental benefit. Hemp waste offers promise, but its real value will depend on how efficiently it can be processed, converted and recovered after use.

As packaging companies look for alternatives to conventional plastics, hemp hurd-based films could become part of a broader material toolbox. The study reinforces the idea that biomass waste streams are not just agricultural leftovers, but potential building blocks for the next generation of lower-impact packaging materials.