Characterization of Reinforcing Web Structures in Needle Punched Nonwoven Composites

The structural parameters of needle punched nonwoven composites have been examined using image analysis system. Fourteen plies of carded webs of E Glass fiber were stacked and needle punched at different punching densities of 15, 30, 45, 60, and 90 penetrations per square centimeter. The needle punched webs were formed into composites with unsaturated polyester resin. The structural parameters examined include the fiber orientation distribution as well as the length changes during the punching process. The mean fiber length was substantially decreased up to 30% with increasing punching densities and the fibers were more randomly distributed at the high punching densities. The fiber orientation factor of the nonwoven composite was decreased with punching densities, which means more random distribution of fibers at higher punching densities.