Innovative concepts for sustainable materials are emerging rapidly, much like flowers blooming in spring. A notable alternative to traditional paper is pollen-based paper derived from sunflowers, which can be reused multiple times due to a distinctive unprinting technique.
A group at Nanyang Technological University in Singapore has developed paper using a unique material: pollen, specifically from sunflowers. This organic substance offers numerous benefits, particularly regarding recycling and sustainability.
"[B]y extending the lifespan of the paper […] we get the maximum value out of each piece of paper we produce,"
said NTU President and Professor Subra Suresh, who co-led the research
Safe, Strong and Sustainable
When considering pollen, allergies are often the first thought that arises. However, there’s no cause for concern—during the production of pollen-based paper, all allergenic substances are eliminated. Quality-wise, pollen-based paper matches traditional paper without any issues. While colors may vary slightly, the image resolution and clarity are on par with conventional options. Additionally, its tensile strength is equivalent to that of standard paper.
This paper takes a significant leap forward in sustainability. Its production process is not only straightforward but also highly environmentally friendly. Furthermore, its recycling capabilities are impressive; thanks to an innovative unprinting method, it can be reused up to eight times.
Easy and Eco-Friendly Production
As previously noted, the production of pollen-based paper is both straightforward and environmentally friendly. The process begins similarly to soap production, where potassium hydroxide is utilized to eliminate the cellular components from sunflower pollen grains. This is followed by converting the pollen into a soft microgel, during which any allergenic substances are also removed. The resulting pollen microgel is then thoroughly cleaned with de-ionized water to eliminate any residues. Finally, the gel is poured into a mold and allowed to air dry, completing the production process.
To prevent bending and curling due to humidity, the pollen-based paper undergoes a stabilization process through immersion in acetic acid. Once this step is completed, the paper is well-prepared for repeated use, allowing it to be utilized multiple times without compromising its integrity.
About the Unprinting Method
The unprinting method is a unique process that allows for the removal of printed content from paper, enabling it to be printed on again. While this technique is not applicable to all types of paper, it is particularly effective with pollen-based paper. This capability enhances the sustainability of the product, allowing it to be reused multiple times while minimizing waste.
The unprinting process involves immersing the paper in an alkaline lab reagent for two minutes, which effectively disintegrates and breaks down the toner layer. Following this, the paper is placed in ethanol for five minutes, leading to a shrinkage effect. After undergoing an air drying process, the pollen-based paper can be reused up to eight times, maintaining its structural integrity and the quality of the printed images throughout multiple uses. This innovative method significantly enhances the sustainability of the paper.
