Component ratio effects of melamine cyanurate and aluminum diethylphosphinate in flame retardant TPU

Melamine cyanurate (MCA) and aluminum diethylphosphinate (ADP) were added to thermoplastic polyurethane elastomer (TPU) in different ratios and additions to prepare flame retardant TPU materials, and their mechanical and combustion properties were systematically investigated. Firstly, the effects of MCA/ADP on the flame retardancy of TPU were investigated by using limiting oxygen index (LOI), vertical burning (UL 94) tests and cone calorimeter test (CCT). The experimental results showed that when the total addition of flame retardant was at 15% and the mass ratio of MCA/ADP was 1/1, the LOI value of TPU can reach 27.4% and pass the UL 94 V-0 rating, and the peak heat release rate was 22% lower than that of pure TPU. Secondly, it was found that the mechanical properties of TPU were minimally affected by the addition of MCA/ADP, and the tensile strength could basically be maintained at about 40 MPa and elongation at break at about 530% at the addition amount of 15%. The microscopic morphology of the residual char of TPU materials were analyzed by scanning electron microscopy (SEM) and the gas-phase pyrolysis products were studied by thermogravimetric Fourier infrared spectroscopy (TG-IR). It was found that the addition of ADP promoted the decomposition of TPU in advance to produce a dense char layer and thus protected the matrix material, while MCA mainly decomposed to produce inert gases such as NH3 to dilute combustible gases. Therefore, the constructed MCA/ADP synergistic flame retardant system exerts excellent flame retardant effect on TPU.

Automated summary

In this study, flame retardant thermoplastic polyurethane elastomer (TPU) materials were prepared by adding melamine cyanurate (MCA) and aluminum diethylphosphinate (ADP) in different ratios and additions, and their mechanical and combustion properties were systematically investigated. The results showed that at a total addition of 15% and a mass ratio of MCA/ADP of 1/1, the TPU achieved a LOI value of 27.4% and passed the UL 94 V-0 rating, with a 22% decrease in peak heat release rate compared to pure TPU. The mechanical properties of TPU were minimally affected by the addition of MCA/ADP, with tensile strength maintained at around 40 MPa and elongation at break at about 530% at the addition amount of 15%. Therefore, the constructed MCA/ADP synergistic flame retardant system exhibits excellent flame retardant effect on TPU.