Flammability properties of polyvinyl alcohol containing new flame retardant system

Abstract

In this work, graphite (G), ammonium iron (II) sulfate (AFS) and aluminium nitrate were added to polyvinyl alcohol (PVA) at 25% loading level to improve its flame retardancy. In addition, PVA/(G+AFS+AN) composite was prepared. The flammability and smoke density of PVA composites were evaluated by UL94 flame chamber, limiting oxygen index (LOI) and smoke density chamber. Vertical flame spread test (UL94V) indicated that PVA composites achieved V0 class in PVA/(G+AFS+AN)and PVA/AFS samples. Horizontal burning rate (UL94H) data showed that PVA composites achieved H0 class. LOI of PVA was enhanced from 19.1% to 21.3%, 25.2%, 26.1% and 27.2% in PVA/G, PVA/AN, PVA/AFS and PVA/(G+AFS+AN)composites, respectively. The maximum specific optical density (Dsmax) of PVA was decreased in all PVA composites due to the formation of protective char layer on polymer surface. The maximum reduction in Dsmax value of PVA was 64% and it was observed in PVA/(G+AFS+AN). XRD analysis of char residue after smoke density test of PVA/(G+AFS+AN) indicated the presence of coquimbite phase, graphite and magnetite in the char residue. Thermogravimetric analysis (TGA) data of PVA and PVA/(G+AFS+AN) composite showed that the new flame-retardant system improved the thermal stability of neat polymer and the temperatures at which 50% (T50%) weight loss takes place were greatly enhanced. In addition, the char residue at 750 ℃ was increased.

Reducing fire hazards and enhancing the thermal stability, acoustical, and UV protection of polyvinyl alcohol using bio-based flame retardant

“…When the temperature exceeds 400°C, PVA backbone degradation is observed. 8 PVA15 composite is also decomposing through two stages. In addition, the values of T 10% , T 50% , T 1max , and T 2max of PVA15 composite are lower than the corresponding values in pure polymer.…”

“…1 Physical blending of PVA with flame retardant materials, which can be organic or inorganic compounds, is a widely used method to prepare flame-retarded PVA. Makhlouf et al 8 added ammonium iron (II) sulfate (AFS) to PVA to improve its flame retardancy. The authors reported that the addition of 25 wt% (AFS) to PVA enhanced its LOI to 26.1%, and the samples achieved V0 in the vertical flame spread test.…”

Poly(vinyl alcohol) Composite Aerogel toward Lightweight, Remarkable Flame Retardancy, and Thermal Insulation Properties by Incorporating Carbon Nanohorns and Phytic Acid

“…Compared with these materials, poly­(vinyl alcohol) (PVA) has garnered significant attention in recent years due to their exceptional advantages, including low cost, good chemical stability, outstanding biocompatibility, and environmental sustainability. However, the limitations of pure PVA include high flammability , (limited oxygen index (LOI) ∼ 19.8%) and superhydrophilicity due to its organic framework composed of abundant hydroxyl groups, which restricts its feasibility in many practical applications. Extensive research has been conducted to improve the flame retardancy of PVA aerogels, particularly by preparing organic/inorganic composite aerogels through the addition of inorganic fillers .…”