Optimization studies for biopolyol production from waste biomass and synthesis of polyurethane foam

In this study, biopolyol was obtained from tomato pulp, an industrial waste, by acid-catalyzed solvothermal liquefaction method, and polyurethane foams were synthesized using this biopolyol. Optimized/experimental design was made according to the liquefaction process, reaction time, reaction temperature and catalyst amount variables, and a model was created. Biopolyols were characterized by determining hydroxyl number, acid number and viscosity values. Hydroxyl numbers of polyols varied between 306-500 mg KOH/g, and viscosity values varied between 318-1070 cP. Foams containing different amounts of blowing agent (water) and additives were synthesized using biopolyols. Secondary waste remaining after liquefaction process (non-liquefied tomato pulp) was used as additive. Average cell size, density, open/closed cell ratio, thermal conductivity and compressive strength properties of the foams were investigated. In foams containing biopolyol and additives, these values varied between 39.33-41.46 mW/m.K and 146.5-160 kPa. The increase in water content in the foam formulation significantly increased the open cell ratio and average cell size, while decreasing the density. As a result of these changes, thermal conductivity increased and compressive strength decreased. On the other hand, the presence of additives slightly decreased thermal conductivity in foams at low additive ratio (1%), while increasing compressive strength.