Synergistic effects of strontium carbonate on a novel intumescent flame‐retardant polypropylene system

Abstract

The effect of a synergistic flame‐retardant system with epoxy resin microcapsule modified ammonium polyphosphate (MAPP) as the primary flame retardant, and strontium carbonate (SrCO3) as the synergistic agent on the flame retardancy of polypropylene (PP) were studied. The flame‐retardant performance of the prepared PP composite samples was analyzed by vertical combustion test (UL94), limiting oxygen index (LOI) test, cone calorimeter test, infrared chromatography (FT‐IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and other technical means. The results showed that when the addition amount of SrCO3 was 1.5 wt%, the LOI reached 36.1%, and the UL‐94 test reached V‐0. Compared with no SrCO3 added sample, the peak heat release rate (PHRR) dropped from 395 to 378 kW/m2. The SEM data showed that the addition of SrCO3 enabled the flame‐retardant system to form a firmer char layer. The TGA data showed that SrCO3 catalyzes the MAPP reaction to form a cross‐linked structure and forms a bridge bond between the two phosphate groups to promote a stable carbon layer. Compared with no SrCO3 added sample, PP composite's tensile strength was increased from 26.78 to 29.42 MPa. Thus, a suitable amount of SrCO3 had a synergistic effect on the flame retardancy of the PP composite and had improved the system's mechanical properties.

Recent Advances in Halogen-Free Flame Retardants for Polyolefin Cable Sheath Materials

“…Moreover, the tensile strength of PP composites enhanced from 26.8 to Moreover, it was found that transition metal ions, such as Fe 3+ , Zr 4+ , Sr 2+ , Zn 2+ , etc., can also be used as catalysts for reactions of dehydrogenation and crosslinking of polyolefin substrates [159]. Chen et al [160] studied the cooperative influence of strontium carbonate (SrCO 3 ) as the cooperative agent on the mechanical performance and flame retardancy of PP/IFR system. The cooperative effect could be observed by the enhanced LOI value (from 36% to 36.1%) and UL-94 grade (from V-1 to V-0) of PP/IFR composites with 1.5 wt.% SrCO 3 .…”

Synergistic Modification of Polyformaldehyde by Biobased Calcium Magnesium Bi-Ionic Melamine Phytate with Intumescent Flame Retardant

“…It has a series of characteristics such as high storage capacity in nature, ultra-high phosphorus content, and excellent metal ion complexation ability, and it can react with organic amine compounds. These are great qualities for it to become a high-efficiency acid source in IFRs and to prepare single-component multifunctional flame retardants and organometallic salt synergists [ 15 , 16 , 17 ]. Cheng et al used phytic acid as an acid source and chitosan and biochar as carbon sources to prepare flame-retardant coatings and applied them to the flame-retardant modification of cotton fabrics.…”

Synergistic effects of fly ash on thermal, combustion, and mechanical properties of polypropylene including intumescent flame retardant

“…Different studies have been conducted to enhance the efficacy of different IFR systems for PP by utilizing various compounds in different ratios 38–40 . Some fillers such as zinc borate, montmorillonite, expanded graphite, sepiolite, clay, calcium carbonate, nickel‐aluminum hydrotalcite, boric acid, mica, and strontium carbonate have been used to reinforce the char layer formed by IFR system, thereby enhancing the thermal/fire resistances of the composites and smoke suppression 41–50 . Furthermore, some improvements in mechanical properties were also reported with the addition of the fillers.…”

“…[38][39][40] Some fillers such as zinc borate, montmorillonite, expanded graphite, sepiolite, clay, calcium carbonate, nickel-aluminum hydrotalcite, boric acid, mica, and strontium carbonate have been used to reinforce the char layer formed by IFR system, thereby enhancing the thermal/fire resistances of the composites and smoke suppression. [41][42][43][44][45][46][47][48][49][50] Furthermore, some improvements in mechanical properties were also reported with the addition of the fillers. Importantly, the incorporation of these fillers reduces the production costs of the composites by replacing the more expensive IFR systems and PP.…”