Low‐melting sulfate glasses as additives to semirigid PVC and their flame retardant and smoke suppressant properties

Abstract

The role of low-melting sulfate glasses (LMSG) as additives on the flame retardant and smoke suppressant properties of semirigid poly(viny1 chloride) (PVC), as well as the mechanism for flame retardancy and smoke suppression, were studied through the Limiting Oxygen Index (LOD test, Smoke Density Rating (SDR) test, DTA-TG, and SEM. The results show that the LMSG have good smoke suppressant properties. When the W C compound contains 40 parts of LMSG, the SDR value will be reduced by about 45%. The Cu2+, Zn2+, Mn2+, and Ni2+ sulfates, as well as MOO,, cause PVC to crosslink and form char, and the melt can protect not only the char formed during combustion and thermal degradation, but also undecomposed polymer. That is the main mechanism for flame retardation and smoke suppression when the additives melt. The mechanical properties of the PVC compounds containing different levels of LMSG were also studied.

Flame Retardant Property of Sb2O3/SnO2 and their Synergism in Flexible PVC

“…The surface of the char of B, C, and D is quite different from that of Sample A (which contains no flame retardant). The pure PVC sample shows a densified structure with a few pores, while the char of Samples B, C, and D shows a porous honeycomb structure (especially Sample D), which can inhibit penetration of oxygen, exit of combustible gases, and penetration of heat into the PVC bulk [27,28]. This can improve the flame retardancy property of flexible PVC and enhance the LOI and char yield.…”

Zinc Hydroxystannate- or Zinc Stannate-coated Calcium Carbonate as Flame Retardant for Semirigid Poly(vinyl chloride)

“…Among the thermoplastics, it ranks second only to polyolefin in total worldwide production volume [1]. However, for many applications, it requires an organic plasticizer, such as di(2-ethylhexyl)phthalate (DOP), added at varying levels to make the PVC material flexible and easy to process [2][3][4]. But it also makes the PVC products easy to ignite and burn, which is dangerous to life.…”

Block it and rock it: Smoke suppressants that form a protective layer in PA 6.6

“…Furthermore, several inorganic materials, such as low melting oxide glasses, spherical silica, metal hydroxides, and clays, enhance the properties of the protective layer, which result in increased flame retardancy and decreased smoke emission. [18][19][20][21][22][23][24][25] The improvement of the protective layer is attributed to the stabilization of char, enhanced cross-linking, and the rearrangement of inorganic particles, such as aluminum hydroxide or silica, on the surface. 23,[26][27][28][29][30] Due to the promising properties of protection layers regarding flame retardancy and smoke emission, this study investigates the influence of condensed-phase-active additives as smoke suppressants (SPs) in AlPi flame-retarded PA 6.6.…”

“…[18][19][20][21][22][23][24][25] The improvement of the protective layer is attributed to the stabilization of char, enhanced cross-linking, and the rearrangement of inorganic particles, such as aluminum hydroxide or silica, on the surface. 23,[26][27][28][29][30] Due to the promising properties of protection layers regarding flame retardancy and smoke emission, this study investigates the influence of condensed-phase-active additives as smoke suppressants (SPs) in AlPi flame-retarded PA 6.6. Of key interest are the interactions between SP, FR, and polymer in conventional loadings for commercial formulations.…”

“…Furthermore, several inorganic materials, such as low melting oxide glasses, spherical silica, metal hydroxides, and clays, enhance the properties of the protective layer, which result in increased flame retardancy and decreased smoke emission. 18–25 The improvement of the protective layer is attributed to the stabilization of char, enhanced cross-linking, and the rearrangement of inorganic particles, such as aluminum hydroxide or silica, on the surface. 23,26–30…”