Paper from tobacco stalks

Everyday, you see people smoking — from students and employees to jeepney drivers, workers, employees and professionals — and that provides livelihood to farmers, manufacturers and small and big entrepreneurs.

Unknown to many, there is yet another product from the tobacco plant: paper for handicraft. Says Irma Yang, an exporter of paper handicraft decors: "Filipino handicraft is one of the most unique and marketable goods highly prized in western countries. Exporters, however, cannot meet the demand for paper-based products due to low supply of cellulose (the fiber that makes up paper)." Cellulose is a major biopolymer that can be found in cotton (94 percent) and wood (45-50 percent).

Dr. Shirley Agrupis and her colleagues from the National Tobacco Administration (NTA) are using tobacco stalks — produced in big volumes yearly as waste — as an alternative source of cellulose. The stalks contain cellulose, lignin, hemicellulose and extractives found in wood.

The team has observed that the conventional process of producing cellulose yields harmful chemicals, In pulping, the use of sodium hydroxide or sodium sulfide and other dignifying chemicals produce black effluents. In bleaching, the use of chlorine-based agents results in chlorinated compounds that form dioxin. Both waste products are hazardous to the environment.

On this note, Dr. Agrupis’ team has come up with technologies that will eliminate the problem. One is bio-mechanical pulping and the other is non-conventional bleaching.

According to NTA Administrator Carlitos S. Encarnacion, "the goal of this project is to introduce appropriate technologies for the farmers to benefit from their own agricultural wastes. It is our hope that in the future, farmers can sell tobacco stalks for added incomes or even produce the pulp and paper on their own. That is the mission of the NTA."

In the bio-mechanical pulping process the pulp is produced with the help of micro-organisms instead of chemicals. Dried tobacco stalks are soaked in water for 24 hours and then crushed by a compactor. The materials are then chipped and treated with fungal strains (Pleurotus astreatus, Phanerochaete chrysosporium, Trametes versicolor and Coriolus versicolor) and cassava-powder-rice medium, a fungal nutrient medium

The nutrient medium helps in degrading lignin but still retains the cellulose amount of the pulp. The nutrient medium serves as "starters" for the fungi before turning into tobacco material as food source. The fiber strength of the fungal treated pulp ranged from 0.5-1.0 mm (considered long) while conventionally treated pulps have shorter fiber length. According to researchers, fiber length has a bearing on the mechanical strength of the pulp: the longer the fibers, the stronger they are.

In non-conventional bleaching, the pulp is bleached using camias, lime and detergent. The camias juice is used in its pure form while lime and detergent are used at 15 percent concentration at 10 percent pulp consistency. This technology does not degrade lignin but decolorizes the polymer. Detergent is most effective in purifying the tobacco stalk pulp.

The researchers measured the mechanical strength of the tobacco stalk pulp: the burst index, tear index, folding endurance and tensile strength.

The burst strength refers to the amount of hydrostatic pressure required to rupture a piece of paper while internal tear resistance is the energy required to propagate an initial tear through several sheets of paper at a fixed distance.

Tensile strength refers to the longitudinal stress a piece of paper can withstand without tearing apart. Stress pertains to the force per unit width of a test specimen. Folding endurance is the measure of the number of double folds a piece of paper 15mm can endure before its tensile strength falls below the standard value of 1 kg. Lime-bleached stalk pulp has the highest mechanical strength.

NTA has been producing paper from tobacco stalk pulp using this technology since 1994. To date, NTA is the only supplier of tobacco hand-made paper.