Trace analyses of flame-retardant in pyrolysis of XPS foams and its revelation for flame-retardant optimization

The objective of this work is to study the detailed effects of flame-retardant on the pyrolysis behaviors of XPS foams. Thermogravimetric experiments are conducted in air atmosphere for flame-retardant and three XPS foams at different heating rates. The results show that the DTG peak of flame-retardant is higher at much lower temperatures than that of the flame-retardant foams and non-retardant one. It surprisingly suggests that the DTG peak of B2-retardant XPS foam is higher than that of B1-retardant one although more flame-retardant has been added into B1-retardant sample during manufacturing. The detailed DTG curves in local temperature ranges (260–360 °C) explain the non-monotonic effects of flame-retardant mass fraction on the pyrolysis behaviors of XPS foams. It is also reminded that the DTG peaks information is not always enough in analyzing the pyrolysis of flame-retardant materials in research and development. Detailed DTG curves in specific temperature ranges might reveal some more important technical and even philosophical principles. Finally, a proper difference between the temperatures for DTG peaks of flame-retardant and the polymers can be one of the key parameters in searching for new flame-retardants for various polymers.