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Team develops wood-derived glass material

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A transparent material similar to glass that is derived from natural bamboo has been developed by a team of researchers at the Central South University of Forestry and Technology (CSUFT) in Changsha, China.

According to the researchers, the glass material, unlike wood-based products, is simultaneously flame-retardant, smoke-suppressant and super hydrophobic.

Traditionally, silica has been the ingredient used to easily and inexpensively manufacture glass. Yet silica-based glass tends to be extremely dense and brittle, while the process for producing it emits planet-warming gases.

As such, the team sought out cleaner ways to produce glass, and turned to transparent materials derived from wood. Apart from its lower carbon footprint, wood reportedly offers improved mechanical strength and thermal insulation properties.

Further, the wood-derived material offers better transparency than silica glass. However, there is the scarcity of raw materials to consider, with industrial wood estimated to be in short supply by 2050. Another challenge encountered in the manufacturing of wood-derived glass is that the polymers used to make the wood transparent also make it vulnerable to fire.

To overcome this hurdle, the researchers used bamboo, with its faster growth and regeneration rate, to make their transparent material. The researchers also turned to bamboo for its similar composition to wood as well as its vertical channels, which offer high porosity and permeability.

To create the transparent glass-like material from bamboo, vacuum-impregnation was employed to introduce inorganic liquid sodium silicate (Na2O·nSiO2) into the delignified bamboo structure. From there, the product underwent a hydrophobic treatment.

“Through this strategy, we can build a 3-layered flame-retardant barrier comprising a top silane layer, an intermediate layer of SiO₂ formed through hydrolysis–condensation of Na₂SiO₃ on the surface, and an inner layer of Na₂SiO₃),” the researchers explained.

During lab tests, the team determined that the bamboo-derived glass had an ignition time of 116 seconds and a heat release of just 0.7 MJ/m². Meanwhile, smoke production from the bamboo-derived glass was also less at 0.063 m².

The transparent material has already been used to make perovskite solar cells, and the researchers reported that the glass demonstrated high light transmittance at 71.6% — a reported improvement of 15.29% in energy conversion efficiency.

An article detailing the team’s findings, “A Novel Flame-Retardant, Smoke-Suppressing, and Superhydrophobic Transparent Bamboo,” appears in the journal Research.