Government research has proven the viability of two unlikely waste products from agricultural processing for their potential as adhesive additives that are not just cost-effective but also environment-friendly and pose no health hazard.
Initial research conducted by the Department of Science and Technology (DOST) and the in partnership with the National Tobacco Administration (NTA) showed the potential of both spent tea leaves and tobacco dust as adhesive additives with potential use for wood-based panels and plywood production.
Wood-based panels are usually bonded by formaldehyde-based adhesives that emit formaldehyde gas which is potentially carcinogenic. Used tea leaves and tobacco dust provide an economical and healthy alternative to commercial adhesives according to research conducted by the DOST in 2015, 2018, and 2020.
Why wood adhesives?
Plywood is a major construction material in the Philippines and in the world. DOST researchers Juanito Jimenez and his group cited in their 2020 study that the projected market demand for plywood was at 223.4 million cubic meters in 2022. The study said that in the Philippines, despite decreasing timber supply, the use of plywood continues to increase due to a rise in construction activities.
However, recent development in regulations of wood-based panels bonded with formaldehyde-based resins poses threats to the use of plywood for indoor applications due to formaldehyde emission (FE) regulation for wood-based panels. Formaldehyde is a known carcinogen that can cause pharyngeal cancer and leukemia in humans.
The DOST studies showed that tobacco stalks, from which tobacco dust is processed, were found to be effective in lessening formaldehyde emissions and in repelling termites. Waste tobacco stalks contain nicotine and other alkaloids that can be potentially toxic or repellant to termites. Tobacco dust can be used as an alternative in the glue line treatment of wood panels.
The use of tobacco stalks which can be grounded to produce tobacco dust may help in the reduction of agricultural solid waste. The use of tobacco stalks may also add additional value to the otherwise discarded material resulting in additional income for tobacco farmers. The DOST research also showed improved plywood resistance to termites due to tobacco dust.
“An increase in shear strength and wood failure up to 8% tobacco particles loading was observed compared with plywood that used commercial glue formulation,” Jimenez and his team said in their research published in 2020.
The study added that stalk and leaf midrib particles from the native (Batek) tobacco (Nicotiana tabacum) were used as an additive to replace wheat and coconut shell flour in urea-formaldehyde adhesive formulations.
“Based on shear strength and wood failure, panels containing 4–8% tobacco particles would pass the requirements of PNS ISO 12466-2. Termite resistance at 12% tobacco particles improved by 43% compared with the control. Thus, tobacco particles can be considered as a more beneficial alternative glue-mix additive in plywood production,” the study added.
Meanwhile, spent tea leaves are rich in polyphenolic compounds that can potentially scavenge formaldehyde gas from plywood. Used tea leaves can also scavenge formaldehyde in wood-based panels such as plywood.
Viability
The tea-flavored drinks industry across the country generates around 18,000 kilos of STL every day. Meanwhile, the National Tobacco Authority estimates that the country’s tobacco waste is around 45 million kilos every year.
Tobacco stalks, meanwhile, can repel termites and also lessen formaldehyde emissions. The National Tobacco Authority estimates that the country’s tobacco waste is around 45 million kilos every year.
The DOST Forest Products Research and Development Institute had recently signed a partnership with Mindanao-based Impasug-ong Integrated Wood Processing and Plywood Manufacturing Inc. for the trial testing of the glue mixtures.
Moro on Tobacco Dust
In November last year, the NTA announced the resumption of the production of its tobacco dust product. In 2009, the NTA developed a tobacco-based molluscicide and fertilizer for inland aquaculture applications. The product was registered under the trade name "NTA Tobacco Dust Plus (TD Plus)" with the Fertilizer & Pesticide Authority.
TD Plus was commercially produced at Tobacco Dust Processing Plant (TDPP) in Brgy. Fernando in Sto. Tomas town in La Union province. However, the processing plant burned down in 2018 which resulted in the temporary stoppage of production of TD Plus production ceased. As of press time, rehabilitation of the plant was being undertaken by the NTA.