Recycling Technology of Fiber-Reinforced Plastics Using Sodium Hydroxide

Glass fiber-reinforced plastics (GFRP) are high strength materials by reinforcing resin with glass fiber, and are increasing annually because FRP is a light weight with high corrosion resistance. However, disposal treatment of it is difficult due to its high stability, and cause illegal waste dumping of big GFRP products, such as ship, bath, tank and so on. In this study, we attempted to convert plastic and glass fiber in the FRP into gas, oil and water glass using sodium hydroxide reaction, respectively. GFRP was cut into the peace with the diameter of 1 cm. Sample peaces (4g) and sodium hydroxide (2g – 12g) put into the reactor, and the reactor was heated with an electric furnace while flowing nitrogen (160 mL/min). After heating to setting temperature (300 – 450 ºC) for 1 h, the reactor was naturally cooled to room temperature. The generated gas and oil during the reaction was collected by gas pack and oil trap, respectively. After cooling, the residue inside the reactor was washed with distilled water, and filtrates to obtain the residual substance, and silicon concentration in the filtrate was measured to calculate the silicon extracted content from GFRP. By using pyrolysis with sodium hydroxide, GFRP can be decomposed by correcting the resin into the gases, such as hydrogen and methane, and glass fiber into soluble salt in order to be extracted into the solution. GFRP can be decomposed by pyrolysis with NaOH above 400oC.