AN ENVIRONMENTALLY FRIENDLY CARTON ADHESIVE FROM ACIDIC HYDROLYSIS OF WASTE POTATO STARCH

OpenAlex İngilizce

In food industries, especially in factories producing potato chips, large quantities of wastes can be generated that can harm aqueous environments. Before the potato chips are produced, at stages such as cutting and slicing the potato, the potato starches from the blade pass into the aqueous medium. The starch in this aqueous medium can be recycled by centrifuging or decanting before discharging. Otherwise, producing energy by sending it to biogas production facilities is a common method. The industrial starch obtained in this way is referred to as a by-product or waste. Thus, these waste starches, which are renewable, low-cost, multi-functional, biodegradable and nontoxic, can be used in different industries by changing their properties with some physicochemical or chemical methods and can be brought into the economy as cardboard adhesive. The aim of this study was to obtain an environmentally friendly cardboard adhesive from the modification of waste potato starch (WPS) by hydrolysis. WPS was homogenized in different amounts of deionized water and isopropyl alcohol (IPA) mixtures (0–135 mL). Subsequently, the mixtures were hydrolyzed by 25 mL of HCl or H2SO4 at different concentrations (0.25–1.25 M). The structure of the modified potato starch (MWPS) was determined by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD), the surface morphology by scanning electron microscope (SEM), the thermal behavior by thermogravimetric (TGA) analysis, and the viscosity by Brookfield viscosimeter. The adhesive property of the MWPS samples was determined as a tensile strength on a “dog-bone shape” cardboards by texture analyzer. The molecular weight profiles of the starch samples were determined by gel permeation chromatography (GPC) and the effect on the mechanical properties of starch was investigated. The molecular weight of starches was obviously decreased by acid hydrolysis. The observed peaks in the FT-IR spectrum were similar in the WPS and MWPS samples, and not affected by the type and concentration of the IPA or acids. In the SEM images, the granules surface of the MWPSs became shrunken and even fractured with the recessed surfaces. As the acid hydrolysis increases, the diffraction of crystalline peaks, and the thermal stability and degradation temperatures decreased. The viscosity significantly decreased with the increasing of the acid concentration. The best adhesive was obtained from the hydrolysis of 0.50 M HCl (25 mL) in 135 mL of water with the strength of 10.90 MPa.