Intercalated hydrotalcite‐like materials and their application as thermal stabilizers in poly(vinyl chloride)

Abstract

The preparation of hydrotalcites with traditional materials is often based on the corresponding salts and alkali solutions. In this study, to facilitate industrial synthesis and take advantage of the lower cost during the process, a Ca–Al–HPO3–layered double hydroxide (LDH) was directly synthesized with calcium hydroxide, aluminum hydroxide, and sodium phosphite powders. X‐ray diffraction, Fourier transform infrared, and scanning electron microscopy analyses confirmed the successful synthesis of the phosphite‐intercalated hydrotalcite. Compared with Ca–Al–CO3–LDH, Ca–Al–HPO3–LDH enhanced the heat stability of poly(vinyl chloride) (PVC) in terms of both short‐term and long‐term stability because phosphite replaced the allyl chloride and reacted with the conjugated double bonds in PVC; this was deduced through a thermal aging test. The composites of Ca–Al–HPO3–LDH, zinc stearate, and calcium stearate had a synergetic effect when added to PVC and exhibited excellent thermal stability. In addition, the phosphite reacted with ZnCl2 in case of the phenomenon of zinc burning. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44896.

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

“…8,9 Every coin has two sides, thus all the thermal stabilities have advantages and disadvantages. 8,16,17 At present, magnalium hydrotalcite as typical Layered Double Hydroxides (LDHs), has been widely used as a high-efficiency long-term stabilizer in calcium and zinc heat stabilization system. 10 Even though organic tin stabilizer conforms to environmental protection, the price is so high that domestic production is quite small.…”

“…Generally, PVC samples are plastified by a double-roller machine and a torque rheometer under a specific temperature usually from 160 to 190 8C for several minutes, the process of which was also a way to mix inorganic products with PVC resin. Sodium stearate (SS) with the formula of CH 3 (CH 2 ) 16 COONa has been identified as a useful surface modifier because of its surfactant property which contains the hydrocarbyl moiety, a hydrophobic group, and could help to integrate well with organic molecular. In addition, owing to the existed H 2 O molecule in interlamination and lots of hydroxyl on the surface, adjacent hydrocalumite particles are easy to band together through hydrogen bond in drying process, thus causing lower heat stability for PVC.…”

Layered double hydroxides as thermal stabilizers for Poly(vinyl chloride): A review

“…The interlayer guests are known to endow LDHs with predominant effect on the thermos-stabilization of polymer (Zhang et al, 2012;Yan et al, 2017). They enable to capture and react with HCl gas by ion-exchange process, thus achieving the purpose of eliminating HCl catalysis.…”

“…The role of LDH additives in absorbing HCl was confirmed experimentally by Ven et al (2000). The reaction mechanism between LDHs and HCl gas proceeds in two steps (Ven et al, 2000;Yan et al, 2017) (Fig. 4): (1) Based on the exchangeability of interlayer guests, the HCl gas reacted with the interlayer guests of LDHs by exchanging the Clions into the interlayer and forming the Cl-intercalated LDHs;…”

Preparation of Magnesium-Aluminum Hydrotalcite by Mechanochemical Method and Its Application as Heat Stabilizer in poly(vinyl chloride)

“…Therefore, there are many kinds of hydrotalcites, which have broad application prospects in the fields of adsorption [ 11 ], medicine [ 12 ], catalysis [ 13 ], electrochemistry [ 14 , 15 , 16 ], flame-retardant [ 17 , 18 ], and photochemistry [ 19 ]. Moreover, it can also be used as a heat stabilizer for PVC [ 20 ]. In the 1980s, hydrotalcite was firstly found that when added to PVC materials had better thermal stability than PVC materials without adding hydrotalcite [ 10 ].…”