Blending cottonseed meal products with different protein contents for cost-effective wood adhesive performances

Authors: PRADYAWONG, SAROCHA - Kansas State University; LI, JUN - Kansas State University; He, Zhongqi; SUN, XIUZHI - Kansas State University; WANG, DONGHAI - Kansas State University; Cheng, Huai; Klasson, K Thomas

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/27/2018
Publication Date: 11/1/2018
Citation: Pradyawong, S., Li, J., He, Z., Sun, X.S., Wang, D., Cheng, H.N., Klasson, K.T. 2018. Blending cottonseed meal products with different protein contents for cost-effective wood adhesive performances. Industrial Crops and Products. 126:31-37. https://doi.org/10.1016/j.indcrop.2018.09.052.
DOI: https://doi.org/10.1016/j.indcrop.2018.09.052

Interpretive Summary: Bio-based environmentally friendly products receive a good global response due to an increase of public concern associated with human health risk and environmental issues. Varieties of natural resources have been studied in order to develop eco-friendly and sustainable products. Like the protein isolate, washed cottonseed meal (WCSM) also contains the protein component. However, it is cheaper and more environmentally friendly in preparation than protein isolate. However, it is critical for industrial standard setup and quality control to understand how the protein content in WCSM affect the adhesion performance of WCSM. Thus, this work evaluated the effect of protein content on, and the range or ratio of protein percentage in WCSM required for, optimal adhesive performance for industrial standard references. While the adhesive strength values were generally higher with higher protein contents, WCSM with 65-70% of protein content demonstrated the bonding performance and flowability comparable to protein isolate within the acceptable standard deviations. Thus, this information could be helpful in quality control and standard setup of protein contents for industrial production of cost-effective WCSM as wood adhesives.

Technical Abstract: Water wash cottonseed meal (WCSM) is an excellent bio-adhesive resource because of its cost-effective extraction process and environmentally friendly performance. To evaluate the effects of protein content on the adhesion performance of WCSM, adhesive blends with different protein contents were formulated from cottonseed protein isolate (CSPI), WCSM, and cottonseed extraction residual (CSIR) in a protein range of 34.9-98.4%. Their rheology, thermal properties, and adhesion performance were measured at pressing temperatures of 100, 150 and 170 °C. The low-protein-content adhesives with a high amount of residual hull and fiber showed poor spreadability and adhesion strength. Protein ratio had a stronger influence than pressing temperature to thermal property and adhesive strength. A strong protein-protein network was found in the CSPI adhesives. The multiple linear regression models could be used to predict the bonding strength affected by protein content and pressing temperature, providing analytical tools for tailoring adhesive formulation and cost-efficiency calculation. The highest protein content (CSPI=98.4%) and pressing temperature (170 °C) provided the best adhesion strength. The wet, dry and soak adhesive shear strength were 2.65, 4.48 and 4.70 MPa, respectively. On the other hand, the blends with 65-70% of protein content demonstrated the bonding performance and flowability comparable to CSPI within the acceptable standard deviations. Thus, this information could be helpful in quality control and standard setup of protein contents for industrial production of cost-effective WCSM as wood adhesives.