Abstract:
Corn, an important economic crop, is grown abundantly in Thailand. After harvesting, corn stalk is considered an agricultural residue with as many as 6000-8000 corn stalks per 1 rai (0.4 acre). It is ploughed up or burnt down in the field. Thus, this study aimed to find potential use of corn stalk in pulp and paper production by finding the optimum pulping conditions and papermaking potential of corn stalk, comparing properties of pulp and paper produced from various parts of corn stalk from different corn cultivars (waxy and field corn), and obtaining optimum ratio between corn stalk pulp and commercial pulp to improve paper properties. Corn stalk was cooked by soda process with various concentration of sodium hydroxide (NaOH). Pulping time was 120 minutes and pulping temperature was 120C. The results showed that the optimum pulping conditions that provided paper with best strength properties (tensile index and burst index) for waxy corn and field corn were 15% and 25% based on oven-dried chip weight, respectively. When corn stalk pulp was used to substitute commercial pulp (hardwood and softwood) at the amount of 25%, 50%, 75% and 100% based on oven-dried pulp weight to improve paper properties, it was found that the pulps from both corn cultivars could improve strength properties (tensile index and burst index) with similar efficacy in all ratios and had better strength properties than the control paper which contained no corn stalk pulp. Therefore, corn stalk residue can be used in pulping and papermaking with good results.