Bean Dreg-Hydrocalumite Composite as a Highly Efficient Thermal Stabilizer for Poly(vinyl chloride)

Bean dreg (BD)-hydrocalumite composites were prepared by a hydrothermal method with BD, Ca(OH)₂, Al(OH)₃, and Na₂CO₃ as raw materials. The samples were characterized by powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and N₂ physical adsorption-desorption. Their properties as a thermal stabilizer for poly(vinyl chloride) were tested using a torque rheometer and static thermal aging method. Compared with traditional hydrocalumite, the crystal size of the BD-hydrocalumite composite was relatively small, which made it exhibit good dispersion and better thermal stability for poly(vinyl chloride). In addition, the effects of preparation conditions on the properties of BD-hydrocalumite as a heat stabilizer were also investigated. Under the conditions of n[Ca(OH)₂/Al(OH)₃/Na₂CO₃] = 4.4:2:1, a BD dosage of 5%, a crystallization temperature of 90 °C, and 19 h, the prepared BD-hydrocalumite showed the best performance, and the dynamic thermal stability time of poly(vinyl chloride) reached 2149 s.