Jixing Xie

The effect of metal ions on thermal oxidative degradation of cotton cellulose ammonium phosphate

The thermal oxidative degradation of cellulose, and of cellulose ammonium phosphate and its metal complexes products were studied by thermal analysis, infrared spectroscopy and elemental analysis. The temperature of decomposition was lower for metal complexes of cellulose ammonium phosphate than those samples untreated by metal ions and the values of char yield were greater for treated cellulose than those untreated. This indicates the metal ions can catalyze the reaction of degradation and form more char.

The synergism of MgCO3 and 2ZnCO3·3ZnO·4H2O as flame retardants and smoke suppressants for flexible poly(vinyl chloride) (PVC)

Abstract MgCO3 and 2ZnCO3·3ZnO·4H2O (AZC) as flame-retardants and smoke suppressants for flexible poly(vinyl chloride) (PVC) was evaluated using limiting oxygen index (LOI), smoke density rating (SDR) tests, scanning electron microscopy (SEM) and thermogravimetry analysis (TGA). The activation energy (Ea) of the original and flame retardant PVCs’ degradation processes was calculated by the Vyazovkin method. The results showed that the AZC can be used as a synergistic agent for MgCO3 as flame retardants agent of flexible PVC. The composites of MgCO3 and AZC cannot only decrease the initial decomposition temperature and increase the weight loss rate in the first stage, but also can promote the char formation in the second stage. The AZC decreased the Ea of the degradation reaction of PVC in the first stage and MgCO3 increased the Ea in the second stage, which means that the AZC combined with MgCO3, catalyzed the dehydrochlorination, promoted the early crosslinking for the PVC compound and improve the stability of the char residue. The SEM results also show that the char residue of MgCO3/AZC treated sample has a continuous and denser structure, which can be used as a barrier for the PVC bulk.