A Study on Circular Economy Material Using Fish Scales as a Natural Flame Retardant and the Properties of Its Composite Materials

Abstract

Fish scales (FSs) are fishery wastes that can cause environmental pollution. This study aimed to solve this environmental problem. FSs were used as a flame retardant for polymer materials, making them valuable. Fish scales were combined with a commercial flame retardant, ammonium polyphosphate (APP), through synergistic effects to reduce the amount of commercial flame retardant. The use of FSs conforms to the concept of a circular economy and lowers costs by reducing the consumption of APP. Thermogravimetric analysis (TGA), integral procedural decomposition temperature (IPDT), pyrolysis kinetics, limiting oxygen index (LOI), the Underwriters Laboratories 94 (UL94) flammability test, scanning election microscopy, Raman spectroscopy, and energy-dispersive X-ray spectroscopy were used to determine the thermal properties, flame retardant properties, flame retardant mechanism, char morphology, and composition of the composites. The TGA results indicated that the addition of 40% flame retardant raised the char residue from 16.45 wt.% (pure EP) to 36.07 wt.%; IPDT from 685.6 °C (pure EP) to 1143.1°C; LOI from 21% (pure EP) to 30%; and UL94 classification from fail (pure EP) to V-0. These results suggest an increase in char residue, which indicates better protection of the polymer matrix material. The improvements in IPDT, LOI, and UL94 classification, which indicate greater thermal stability, lower flammability (from flammable to fireproof), and higher flammability rating (from fail to V-0), respectively, suggest that the composite material has favorable thermal properties and is less inflammable.

Curing behavior, mechanical, and flame‐retardant properties of epoxy‐based composites filled by expandable graphite and ammonium polyphosphate

“…For instance, when the addition amount of A‐E was 9.1 wt%, T 5 , T 10 , and T max got their minimum values, which dropped from 371.2 to 316.4°C, from 380.5 to 330.1°C and from 395.6 to 360.3°C, respectively. The reason behind this observation is related to the presence of P element in the A‐E filler, which triggered the pyrolysis of E‐D/A‐E composite at lower temperature 39 . In addition, the Y c for E‐D/A‐E 5 is about 30.46% which is 11.57% higher than that of the E‐D/A‐E 1.…”

“…The next stage (about 360 ~ 395°C) was primarily related to the pyrolysis of E51 and DGED resins. The final stage was the dehydration of PPE near 450°C to obtain P 2 O 5 , and so forth 39,42 . In addition, the V max for all the E‐D/A‐E composites are lower than those of the neat resin revealing that A‐E flame retardants postpone the thermal decomposition of materials at higher temperature 43 …”

Exploiting Waste towards More Sustainable Flame-Retardant Solutions for Polymers: A Review

“…FSs can enhance the fire resistance of composites as a synergistic agent. By adding FSs to APP, Liu et al [90] found that the LOI went from 21.2% to 36.2% and the UL-94 test went from fail to V-0 rate. This indicated that the composite was less likely to catch fire at high temperatures.…”