Effects of fiber surface treatments on mechanical properties of wood fiber-cement composites

The purpose of this research was to determine the effects of treated and untreated hardwood, kraft softwood, and newsprint wood fibers on the 7- and 28-day bending strength, compressive strength, and toughness values for wood fiber-cement composites. Untreated and acrylic- or alkylalkoxysilane-treated hardwood, kraft softwood, and newsprint wood fibers used in wood fiber-cement composites resulted in different bending and compression properties. Fiber characteristics along with different chemical treatments influenced the composite properties. Compressive strength decreased for all fiber types and chemical treatments compared to the neat cement controls. Bending strength values for all wood fiber composites were higher than the neat cement control specimens. Both the acrylic emulsion and alkylalkoxysilane treatments provided improvements in the bending strength values compared to the untreated wood fiber-cement composites. Toughness improved for all untreated and treated wood fiber-cement composites compared to the neat cement control specimens. The toughness value results for the alkylalkoxysilane-treated fibers were similar to the acrylic-treated fibers in that the longer kraft softwood fiber-cement composites had the highest toughness values compared to the other fiber groups.