The effect of sodium stearate-modified hydrocalumite on the thermal stability of poly(vinyl chloride)

Hydrocalumite as a new-type of thermal stabilizer used in poly(vinyl chloride) resin had been well prepared by using precipitation transformation method. The as-prepared hydrocalumite was then modified by sodium stearate in different condition including temperature, stirring time, and the amount of sodium stearate. Scanning electron microscopy tests demonstrate that hydrocalumite had been well modified. Illustrated by activation grade, the static oven heat aging experiments and the rate of thermal weight loss, it turns out that the best modification condition is when the addition of sodium stearate is 6% of hydrocalumite (wt), the reacting temperature is 90 degrees C, and the stirring time is 100 min. Static thermal aging test shows that the aging time got improved at least 30 min under the high temperature of 190 degrees C, and the time when Congo red test paper began to turn blue for modified hydrocalumite is 20 min longer than that of unmodified hydrocalumite. All results turn out to be that the hydrocalumite modified by sodium stearate in such condition had good compatibility with poly(vinyl chloride) and presented better thermal stability. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45758.