Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2013
Publication Date: 3/18/2013
Citation: Cheng, H.N., Dowd, M.K., He, Z. 2013. Investigation of modified cottonseed protein adhesives for wood composites. Industrial Crops and Products. 46:399-403.
Interpretive Summary: Wood adhesives are needed for the manufacturing of wood composites. In 2006 about 4 billion pounds of adhesives (100% active basis) are needed in the U.S. and Canada for various wood uses. Most adhesives currently used are based on urea-formaldehyde and phenol-formaldehyde resins. There has been a lot of interest in soy proteins in the past 15 years in view of the potential hazards of formaldehyde and the interest in renewable feedstock. Several soy protein products have been commercialized. However, cottonseed proteins have not received much attention in the past 15 years. Since cotton is a major crop in the south in the U.S., it is useful to find out if cottonseed protein can be a viable alternative to soy protein in adhesive formulations. We have used both unmodified and modified cottonseed protein and tested them on maple wood veneer for adhesive strength. Under the experimental conditions employed, the adhesives based on unmodified cottonseed protein and cottonseed protein modified with sodium dodecyl sulfate give better performance than the adhesives based on modified or unmodified soy protein. Thus, cottonseed protein appears to be a viable alternative to soy protein for wood adhesives applications.
Technical Abstract: Several modified cottonseed protein isolates were studied and compared to corresponding soy protein isolates for their adhesive properties when bonded to wood composites. Modifications included treatments with alkali, guanidine hydrochloride, sodium dodecyl sulfate (SDS), and urea. Wood composites bonded with cottonseed protein exhibited higher shear strength relative to modified or unmodified soy proteins. Cottonseed protein with SDS treatment gave comparable or better shear strength than unmodified cottonseed protein. Wood composites bonded with unmodified or SDS-modified cottonseed protein also showed superior retained strengths on a boiling test. Thus, a cottonseed protein adhesive (with or without SDS modification) seems to be a viable alternative to soy protein adhesives for wood composites.