Location: Commodity Utilization ResearchTitle: Effects of particle size on the morphology and water- and thermo-resistance of washed cottonseed meal-based wood adhesives
Submitted to: Polymers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2017
Publication Date: 12/5/2017
Citation: He, Z., Cheng, H.N., Klasson, K.T., Olanya, O.M., Uknalis, J. 2017. Effects of particle size on the morphology and water- and thermo-resistance of washed cottonseed meal-based wood adhesives. Polymers. 9(12):675. https://doi.org/10.3390/polym9120675.
Interpretive Summary: Water-washed cottonseed meal (WCSM) is promising as biobased wood adhesives. For promoting the practical application, we prepared WCSM products with three grinding treatments, examined their morphology, and tested the dry, wet, soaked, and heat shear strength of on bonding white oak and Douglas fir wood strips. Microscopic images showed grinding to small fine particles could alter the morphology of these particles with more fracturing and overlapping features, and enriched the mineral contents in the particle surface. Data of the four adhesive strengths with the two types of wood strips demonstrated that these WCSM products were suitable for plywood wood bonding with non-structural interior applications. Information derived from this work increases the performance knowledge of WCSM for developing the industrial standards of WCSM as wood adhesives.
Technical Abstract: Water wash of cottonseed meal is more cost-efficient and environment-friendly than the protein isolation which involves alkaline extraction and acidic precipitation. Thus, water-washed cottonseed meal (WCSM) is more promising as biobased wood adhesives. In this work, we examined the effects of the particle size on the morphology and adhesive performance of WCSM. Pilot-scale produced and dried WCSM was treated by three grinding methods: 1) ground by a hammer mill and passed through a 0.5-mm screen, 2) further ground by an UDY mill and passed through a 0.5-mm screen, or 3) further ground by a ball mill and passed through a 0.18-mm screen. Micro morphological examination revealed two types of particles. The filament-like particles were mainly fibrous materials from residual linters. Chunk-like particles were more like aggregates or accumulations of small particles with proteins as the major component. Further grinding of the 0.5-mm Hammer product with the Cyclone and Ball mill led to more fine (smaller) particles in WCSM products. The impact of further grinding on the dry and soaked adhesive strengths was minimal. However, the decrease of the hot and wet strengths of WCSM products by the additional grinding was significant (P=0.05). Data presented in this work is useful in developing the industrial standards of WCSM products used in wood bonding.