In the race towards sustainable construction, bamboo is rapidly outpacing traditional materials. It is truly earning its place as the green steel of the 21st century. With a tensile strength that rivals steel and a growth rate that shames conventional timber, this versatile grass is revolutionizing the way we build, combining eco-friendly credentials with unparalleled durability and style.
Traditionally, bamboo is used for scaffolding and as a framework for walls, roofs, and floors. However, more recently, bamboo has been playing an increasing role in modern sustainable buildings. A prime example is the magnificent Arc at the Green School in Bali, made from a series of bamboo arches, each spanning 19 meters.
Now, a team of researchers from Central South University of Forestry and Technology (CSUFT) in China has pushed the limits of bamboo, turning it into a transparent material — basically glass.
Furthermore, this new material features a three-layered flame-retardant barrier that effectively reduces heat release, slows flame spread, and suppresses toxic smoke and carbon monoxide emissions.
The Promise and Limitations of Current Glass Alternatives
Silica glass has been a staple in the construction industry for decades. In 2020 it reached a global production of 130 million tons. While it offers high transparency and uses readily available raw materials, traditional silica glass struggles with brittleness, high density, and significant CO2 emissions during manufacturing.
As an alternative, transparent wood has recently garnered attention for its environmental benefits and excellent mechanical properties. Transparent wood could soon find uses in super-strong screens for smartphones; in soft, glowing light fixtures; and even as structural features, such as color-changing windows. However, its use is limited by global wood scarcity, flammability due to polymer content, and functional properties.
Bamboo: A More Sustainable and Efficient Alternative
Bamboo, known for its rapid growth and high yield, reaches maturity within four to seven years. It also produces four times the output of wood per acre as oak. Although it is technically a grass, bamboo is chemically similar to wood. Its structure is highly porous and permeable, making it suitable for creating transparent composite materials.
The CSUFT team used a vacuum-impregnation technique to infuse inorganic sodium silicate into the delignified (removal of cellulose) bamboo structure, followed by a hydrophobic treatment. This process forms a three-layered flame-retardant barrier, significantly enhancing bamboo’s fire resistance and mechanical properties.
The transparent bamboo developed by the team boasts impressive properties: a long ignition time of 116 seconds, low total heat release, minimal smoke production, and low peak CO concentration. Although transparent, it is mechanically strong, with high bending and tensile moduli.
Furthermore, when used as a substrate for perovskite solar cells, the material shows high light transmittance (71.6%) and a fog value of 96.7%, enhancing power conversion efficiency by 15.29%.
The researchers envision a future where we fabricate this transparent bamboo on a large scale for various applications, including green flame-retardant glass and optical devices. This development opens new avenues for sustainable and efficient building materials, contributing to greener construction practices worldwide.
The findings have been published in the journal Research.
