Researchers at the Central South University of Forestry and Technology (CSUFT) in Changsha, China, have created a groundbreaking transparent material from natural bamboo that resembles glass.
This new material sets itself apart from traditional wood-based products by being flame-retardant, smoke-suppressant, and super hydrophobic, according to a press release from the university.
Traditionally, silica has been the primary component in glass production, a practice that has seen a demand of over 130 million tons in 2020. While producing silica-based glass is cost-effective and straightforward, it results in a product that is dense, brittle, and during its production, emits greenhouse gases. Thus, the search for an eco-friendly alternative is critical.
In recent times, there has been a rising interest in developing transparent materials from wood, due to their lower environmental impact and superior mechanical strength and thermal insulation. However, the challenge with wood is its limited availability and the flammability of the transparent wood derived from it.
To address these issues, CSUFT researchers turned to bamboo, a material known for its rapid growth and regeneration capabilities. Caichao Wan from the College of Materials Science and Engineering at CSUFT highlighted that bamboo can be harvested for building purposes in just four to seven years and yields four times as much per acre compared to traditional wood, earning it the nickname “the second forest”.
The team leveraged the high porosity and permeability of bamboo’s vertical channels. They introduced an inorganic liquid sodium silicate (Na2O·nSiO2) into the delignified bamboo using a vacuum-impregnation process. This was followed by a hydrophobic treatment to create a three-layered, flame-retardant barrier. This barrier includes a top layer of silane, a middle layer of SiO2 formed through the hydrolysis-condensation of Na2SiO3, and an inner layer of Na2SiO3.
Testing revealed that the bamboo-based glass has an ignition time of 116 seconds and a minimal heat release of 0.7 MJ/m2, with reduced smoke production measured at 0.063 meters square. It also exhibited improved mechanical strengths, including bending and tensile strengths.
Moreover, when used in perovskite solar cells, the material achieved a light transmittance of 71.6 per cent, resulting in a 15.29 per cent increase in energy conversion efficiency, showcasing its potential for wide-ranging applications.
