Thermal stabilization of poly(vinyl chloride) by hydrotalcites, zeolites, and conventional stabilizers

Abstract Unwanted discoloration and degradation of Poly(vinyl chloride) (PVC) at processing temperatures is a matter of concern to the industrial community. Many formulations have been suggested, but to meet environmental regulations and today's market demand, a new combination of stabilizers has been designed in order to explore the probable mechanism of stabilization. A combination of hydrotalcite, zeolite, calcium stearate, and magnesium acetylacetonate is proposed. Thermal behavior in terms of released HCl and visual color examination for color stability have been investigated. Results indicate that both hydrotalcite and zeolite behave as long‐term stabilizers. In a PVC formulation having 2 phr of hydrotalcite or zeolite, the evolution times for 2 mmol of HCl were 497 and 337 min, respectively, at 180°C, but when a part of these stabilizers was replaced by some other stabilizer, a noticeable change in HCl evolution time was observed. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers