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Shear strength and water resistance of modified soy protein adhesives
Author(s) -
Sun Xiuzhi,
Bian Ke
Publication year - 1999
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-999-0115-2
Subject(s) - soy protein , adhesive , water resistance , composite material , materials science , soy flour , shear strength (soil) , delamination (geology) , polymer , chemistry , food science , layer (electronics) , soil water , paleontology , environmental science , tectonics , biology , soil science , subduction
Soy protein polymers recently have been considered as alternatives to petroleum polymers to ease environmental pollution. The use of soy proteins as adhesives for plywood has been limited because of their low water resistance. The objective of this research was to test the water resistance of adhesives containing modified soy proteins in walnut, maple, poplar, and pine plywood applications. Gluing strength and water resistance of wood were tested by using two ASTM standard methods. Glues with modified soy proteins had stronger bond strength than those containing unmodified soy proteins. Plywood made with glue containing urea‐modified proteins had higher water resistance than those bonded with glues containing alkali‐modified and heat‐treated proteins. After three 48‐h cycles of water‐soaking, followed by 48 h of air‐drying, no delamination was observed for either walnut or pine specimens glued with the urea‐modified soy protein adhesives. Gluing strength for wood species with smooth and oriented surface structure was lower than for those with rough, randomly oriented, surface structures. Wood species with greater expansion of dimensions during water‐soaking had a higher delamination rate than those showing less expansion.