Size-dependent effect of MgAl-layered double hydroxides derived from Mg(OH)2 on thermal stability of poly(vinyl chloride)

Developing green thermal stabilizer for poly(vinyl chloride) (PVC) today is a great challenge for materials as polymer filler. Here, the “salt-oxide/hydroxide” route in mild conditions is used to fabricate a series of Mg2Al-CO3-LDH samples from Mg(OH)2 precursors with different average particle sizes from 202 ± 10 nm to 334 ± 13 nm. A linear correlation is observed for the lateral size of the platelets between Mg2Al-CO3-LDH samples and their associated Mg(OH)2 precursors. After surface-organo-modification (SOM), organophilic Mg2Al-CO3-LDH samples are found to be highly dispersed into PVC and investigated as environment-friendly thermal stabilizers. From the static/dynamic tests, the performances are strongly enhanced and related to the particle size of the LDH stabilizer, with the yellowish color aspect appearing later than for the commercial HT-3/PVC. Among the LDH series, the platelets with an average particle lateral size of about 220 ± 10 nm perform the best for the thermal stability for PVC polymer. Among the series, the corresponding PVC composite film presents comparatively the minimum color value in static/dynamic discoloration test, exhibiting the longer ignition time for proton initial release as well as the longer stability time in dehydrochlorination test. It underlines that the salt-oxide/hydroxide route is an efficient and environmentally friendly process in producing high-performance green LDH stabilizer for PVC.