The Manufacturing of Wet-laid Hydroentangled Glass Fiber Composites For Industrial Applications

Abstract

The main focus of this research is to make a composite of sufficient strength from glass fibers using low melt polyester or bicomponent (polyester/polyethylene sheath/core) fibers as binder fibers for nonwoven preforms. A wet-laid hydroentangled sheet consisting of a blend of glass and low melt binder fibers is used to make compression molded composite. An appropriate white water recipe for dispersing glass and binder fibers was obtained after personal conversation with Owens Corning Company and after image analysis of the trial sheets. The amount of defects in the fabric was analyzed and optimum time of dispersion was established. 6 layers of wet lay sheets were stacked and hydroentangled to get a high weight per unit length single hydroentangled sheet that is then heat pressed. When heat pressed, the binder fibers in the blend melt, adhere to the glass fibers and form a composite.

These composites were tested for stiffness, toughness and flexural strength. An instron machine was used for tensile and 4-point bending tests. Stress strain curves were obtained and the secant modulus at breaking strain was determined. The area under the curve was measured determine the toughness of the material. The tensile strength and toughness increased significantly with increasing glass fiber content of up to 30-40%, after which the strength of the composite decreases. This may be caused by the reduction in binding points and lower adhesion between the glass fibers resulting in lower tensile and flexural strength.

The innovative aspect of this research is in the manufacturing of composites using glass fibers along with binder fibers. Some of the current composite manufacturing techniques use resin to bind the fibers/sheets. Resins are costly and also, not environment friendly. By using binder fibers, the need of using resin is eliminated. Elimination of resin and manufacture of high strength low cost composites with more process flexibility is an imperative objective of this research.