Flame retardancy of polyurethane foams prepared from green polyols with flame retardants

Abstract

Polyurethane foams (PUFs) were synthesized using bis(2-hydroxyethylene terephthalate) (BHET), 1,4-cyclohexanedimethanol (CHDM), and polycaprolactone diol (PCLD), and their flame retardancies were investigated. BHET and CHDM are eco-friendly chemicals derived from waste polyethylene terephthalate, and PCLD is a precursor monomer used for synthesizing biodegradable polymers. Expandable graphite (EG) and tris(1-chloro-2-isopropyl) phosphate (TCPP) were used as flame retardants. For conventional PUFs prepared with an aliphatic polyol, thermal stability was significantly enhanced with EG and TCPP through thermogravimetric analysis (TGA) and microcombustion calorimetry (MCC). PUFs prepared with BHET and CHDM exhibited higher thermal stability than conventional PUFs. This is attributed to the alicyclic and aromatic ring structures, which contribute to thermally stable char formation during pyrolysis. PCLD was introduced as an additional polyol, as well as a possible flame retardant, without the addition of EG and TCPP. PUFs were successfully prepared and exhibited improved resilience to burning up to 300 C due to the intrinsic thermal stability of PCLD. The limiting oxygen index (LOI) indicated that PUFs containing BHET moiety exhibited higher LOI values, whereas PUFs prepared with PCLD showed the lowest LOI value. PCLD can be used as a polyol; however, additional flame retardants are needed to obtain high flame retardancy for PUFs.

Fire-Retardant Flexible Foamed Polyurethane (PU)-Based Composites: Armed and Charmed Ground Tire Rubber (GTR) Particles

“…At the same time, the highest values of elongation at break were noted, which, however, decreased with GTR content due to increased heterogeneity of structure. The incorporation of FRs caused a noticeable reduction in mechanical parameters, which can be attributed to the plasticizing effect of TCPP, which has been repeatedly reported in the literature [ 69 , 70 ]. The presence of TCPP weakens the interactions between PU macromolecules, affecting the mechanical performance of the final material.…”

Intelligent Gas Detection: g-C3N4/Polypyrrole Decorated Alginate Paper as Smart Selective NH3/NO2 Sensors at Room Temperature

“…A higher oxygen index indicates stronger flame retardancy of the material. 30 Figure 2f shows that traditional cellulose paper has the lowest LOI, while composite paper has the highest LOI, confirming the higher flame retardancy of the flexible sensor. Figure 3a, d shows the response curves of the AP@g-CN/ PPy sensor with different PPy contents to 1 ppm of NH 3 and 1 ppm of NO 2 , respectively.…”

Single‐catalyst reactions from depolymerization to repolymerization: Transformation of polyethylene terephthalate to polyisocyanurate foam with deep eutectic solvents

“…[30][31][32] Ammonium polyphosphate (APP) is a common halogen-free phosphorus-nitrogen-based flame retardant. [33][34][35] Thus, these flame retardants could be used for PIRFs for safe use in different applications.…”

“…Expandable graphite (EPG) is an inorganic, intumescent, halogen‐free flame retardant 30–32 . Ammonium polyphosphate (APP) is a common halogen‐free phosphorus‐nitrogen‐based flame retardant 33–35 . Thus, these flame retardants could be used for PIRFs for safe use in different applications.…”