Transparent wood could replace plastics through optimal production techniques, find Indian researchers

Transparent wood production process from natural and delignified wood systems (Image crredit: Dr. Prodyut Dhar). 

24 Oct 2022 --- Transparent wood could replace materials like PE and glass in packaging products, according to a recent study by Indian scientists. The findings are based on life cycle analyses (LCA) of transparent wood production methods and show that the material has a lower environmental footprint than common plastics.

The study was conducted at the Indian Institute of Technology’s (BHU) School of Biochemical Engineering in Uttar Pradesh, India. The research is published in the journal Science of The Total Environment.

Study author Prodyut Dhar tells PackagingInsights that the findings could be highly significant for the packaging sector, wherever see-through plastics are used.

“The most surprising outcome of the study was that transparent wood would generate lower environmental impacts than PE after its disposal. This will help develop sustainable alternatives to common transparent packaging,” he says.

“Transparent wood generates less environmental impact than PE during its end-of-life. PE is a very widely used material for food packaging. Our findings suggest that transparent wood can be applied to replace ecologically harmful PE for application in the food industry.”

Wood could become a standard material for transparent packaging material.Optimizing production
The study aimed to delineate different methods for producing transparent wood and assess the environmental footprint of each. Currently, wood is made transparent by removing its lignin content – a naturally occurring biopolymer – through various techniques.

The researcher’s cradle-to-gate LCA analysis suggests that using sodium hydroxide, sodium sulfite, hydrogen peroxide-based delignification and epoxy infiltration are techniques with the lowest environmental impacts.

Employing these findings could generate approximately 24% less global warming potential and around 15 % less terrestrial acidification than the commonly used methods of sodium chlorite delignification and polymethyl methacrylate infiltration, according to the study.

“The most crucial aspect of the current research was the evaluation of the ecological impacts of common strategies used for transparent wood production at the laboratory and industrial scale,” explains Dhar.

Scaling up challenges
Dhar asserts that more research must be conducted to improve methods of transparent wood production further and optimize energy usage at an industrial scale.

“Based on the current study’s findings, research toward the development of eco-friendly materials for infiltrating the wood matrix is required,” he says.

“It will make the process of transparent wood production more [environmentally] sustainable. The currently used polymers like methyl acrylate are toxic to the environment and thus need to be replaced with non-toxic polymers.”

Taking the findings from the laboratory to industrial-scale production will be the next step, Dhar continues.

“The current challenge in scaling up transparent wood production is the comparatively large amount of energy used at the industrial scale, which needs to be optimized to decrease the environmental impacts of transparent wood and make the process less energy intensive.”

However, the modeled industrial-scale production shown through the study’s alternative techniques has lower electricity consumption (98.8%) and environmental impacts than the laboratory scale – 28% less global warming potential and approximately 97% less human toxicity.

By Louis Gore-Langton

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