Investigation of modified cottonseed protein adhesives for wood composites

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 hot water test. Thus, a cottonseed protein adhesive (with or without SDS modification) seems to be a viable alternative to soy protein adhesives for wood composites.

► Cottonseed and soy protein isolates were studied for their adhesive properties when bonded to wood composites.
► Treatments with alkali, guanidine hydrochloride, sodium dodecyl sulfate (SDS), and urea were also carried out on the proteins.
► Adhesives from unmodified and SDS-modified cottonseed proteins exhibited higher shear strength than modified or unmodified soy proteins.
► Unmodified and SDS-modified cottonseed proteins also showed superior retained strength on a hot water test.
► The results suggest that cottonseed protein can be a viable alternative to soy protein for use in wood adhesives.