Environmentally Friendly Process for Making Paper Pulp Used for Hand-Made Paper from Banana Pseudostem after Harvesting

摘要

In Thailand, the economic value of hand-made paper made mainly from paper mulberry (Broussonetiapapyriferra Vent.) is more than 100 million USD each year. However, a major problem in productionprocess has arisen due to the inconsistency supply of raw material, thus obstructing an expansion of the industry.To solve the problem another raw material is needed. Banana is the promising one to be a substitute as itis one of important economic crops commonly found in Thailand. Each year, banana plants are typically cutdown and thrown away after harvesting of banana bunches. Although the banana pseudostem contains highmoisture, the cellulose contents are considerably high which are suitable to be used as paper pulp. However,sodium hydroxide (NaOH) currently used during pulping process by most manufacturers has generated largeamounts of toxic black liquor afterward which causes waste water problem if no special treatment is applied.Therefore, the objectives of the study are to obtain an alternative raw material for hand-made paper whileadding value to the harvested banana pseudostem and developing environmentally friendly process for makingpaper pulp. Firstly, the chemical compositions of bananapseudostem (Musa (AA group) cv. Kluai Khai)were determined. Then, the paper pulp was made from banana pseudostem using 18, 20 and 22% potassiumhydroxide (KOH) instead of NaOH in order to obtain suitable conditions. Finally, the standard sheets of bananapaper were made and their mechanical properties such as basis weight, thickness, tensile index, tear indexand bursting index etc. of the paper were determined. The results showed that it was possible to use KOHin making paper pulp for hand-made paper as it could help reduce waste water problem. An increase in KOHconcentrations helped reduce the kappa number of paper pulp and the pulp became softer, but the yield decreased.Although an increase in KOH concentrations significantly (p<0.05) helped reduce the kappa numberfrom 33.19 to 30.38, the tensile, tearing and bursting indices obtained from the paper made from banana pulpusing 18, and 20% KOH were not significantly different (p>0.05). Thus, 18% KOH is sufficient to eliminatelignin from banana pulp to make good quality hand-made paper with lower cost than 20% KOH. The bananapaper had a potential to use either for handicraft or packaging