This article is the first to describe a process of manufacturing engineered wood composites that combine two nonwoven textile technologies: bicomponent fiber and needle punching. Hardwood fiber was blended with 10 percent urea formaldehyde and formed into mats. The mats were sandwiched with polypropylene/polyester bicomponent fibers and then needle punched. Needle punching was done by means of barbed needles that oscillated in a vertical direction with regard to the surface of the fiber mat. The barbed needles mechanically interlaced the bicomponent web to the wood-fiber mat and pulled some of the polymer fibers through the thickness direction of the mat. During hot pressing, the polypropylene sheath of the bicomponent fiber flowed, bonded with adjacent wood fibers, and coalesced with the sheath of the adjacent bicomponent fibers. The mats were pressed until the urea formaldehyde was fully cured. Bending and tensile properties of the needle-punched wood composite were assessed and compared with medium-density fiberboard (MDF). An average increase in storage modulus of 40 percent was observed for the 640-kg/m3 panels and 48 percent for the 550-kg/m3 panels. A mean longitudinal tensile modulus of 923 MPa was measured for the laminate panels. This is an improvement in tensile modulus of elasticity of almost 34 percent over the wood-fiber core material.
Contributor Notes
The authors are, respectively, Postdoctoral Fellow, Associate Professor, and Associate Professor, Dept. of Forest Biomaterials, North Carolina State Univ., Raleigh (hhvandyk@ncsu.edu, pperalta@ncsu.edu, ilona_peszlen@ncsu.edu); and Associate Professor, Dept. of Textile Engineering, Chemistry and Sci., North Carolina State Univ., Raleigh (pam_banks-lee@ncsu.edu). This paper was received for publication in June 2009. Article no. 10640.
*Forest Products Society member.