Manufacture and Properties of Citric Acid-Bonded Composite Board made from Salacca Frond: Effects of Maltodextrin Addition, Pressing Temperature, and Pressing Method

Abstract

Non-woody fiber is a sustainable resource for composite products. In this study, salacca frond was used as a raw material, and the effects of citric acid-maltodextrin composition ratio, pressing temperature, and pressing method were investigated. The boards were manufactured under the conditions as follows: single-step press method, adhesive contents 20 wt%, pressing temperature (180 to 200 °C), and adhesive composition of citric acid/ maltodextrin (100/0; 87.5/12.5; 75/25; 62.5/37.5; 50/50 wt%). A three-step press cycle method was also applied to reduce the pre- drying time before hot pressing. The total pressing time was 10 min, and the breathing stage was applied at various times after the starting time. The results showed that salacca frond is a potential material for composite board. The addition of maltodextrin in certain ratios improved the mechanical properties. The mechanical properties of board prepared using citric acid/maltodextrin satisfied the requirement of the JIS A 5908 type 13 (2003) standard. Infrared analyses indicated that carboxyl groups of citric acid react with the hydroxyl groups of the maltodextrin and salacca frond. Furthermore, the three-step press cycle method was more effective than the single-step press method. Adding a breathing stage improved the quality of citric acid/maltodextrin bonded composite board.