Location: Commodity Utilization Research
Title: Utilization of citric acid in wood bondingAuthor
He, Zhongqi | |
UMEMURA, KENJI - Kyoto University |
Submitted to: Book Chapter
Publication Type: Book / Chapter Publication Acceptance Date: 3/8/2016 Publication Date: 2/14/2017 Citation: He, Z., Umemura, K. 2017. Utilization of citric acid in wood bonding. In: He,Z., editor. Bio-based Wood Adhesives-Preparation, Characterization, and Testing. Boca Raton, Florida: CRC Press. pp. 221-238. Interpretive Summary: Citric acid (CA) exists most notably in citrus fruits so that it is named likewise. As a commodity chemical, CA is produced in a large scale by fermentation with worldwide annual production at approximately 1.6 x 106 Mg. In this chapter, we first briefly review the applied research and methods for commercial production of CA. Then we synthesize and discuss the recent research on CA as a wood adhesive additive. For the purpose of wood bonding, CA can serve as a minor additive, functioning as a cross-linking catalyst, a cross-linking agent, or a dispersing agent to improve the adhesive strength and/or operational properties (such as viscosity). CA, with or without sucrose, can also be a major adhesive component in manufacturing fiber and particleboards with a variety of lignocellulose raw materials. These laboratory research accomplishments demonstrated that application of CA as a renewable natural adhesive for wood and lignocellulosic composites is possible. Further effort is ongoing in optimazing practical manufacture conditions for specific types of wood-based molding and medium or low density lignocellulosic particle boards using CA as an adhesive. Technical Abstract: Citric acid (CA) is a weak organic acid. It exists most notably in citrus fruits so that it is named likewise. As a commodity chemical, CA is produced on a large scale by fermentation. In this chapter, we first briefly review the applied research and methods for commercial production of CA. Then we synthesize and discuss the recent research on CA as a wood adhesive additive. For the purpose of wood bonding, CA can serve as a minor additive, functioning as a cross-linking catalyst, a cross-linking agent, or a dispersing agent to improve the adhesive strength and/or operational properties (such as viscosity). CA, with or without sucrose, can also be a major adhesive component in manufacturing fiber and particleboards with a variety of lignocellulose raw materials. The formation of ester linkages between CA and (ligno)cellulose molecules (raw materials and/or sucrose) developed adhesiveness and contributed to the good physical properties of the particle boards made with CA. These laboratory research accomplishments demonstrated that application of CA as a renewable natural adhesive for wood and lignocellulosic composites is possible. Further effort is ongoing in optimazing practical manufacture conditions for specific types of wood-based molding and medium or low density lignocellulosic particle boards using CA as an adhesive. |