In-situ polymerized tourmaline/polypyrrole/lignocellulose aerogel for flame-resistant and intelligent fire alarm...

Fires in buildings made of woody materials pose threats to human lives and property. Therefore, an intelligent, efficient sensors made of lignocellulosic materials for early fire warnings that can detect fires quickly and exhibit satisfactory flame retardancy is urgently needed. In this study, a flame-retardant lignocellulose aerogel (TPLA) with a thermosensitive alarm sensor response is prepared by the vacuum impregnation of tourmaline particles (TPs) and in-situ polymerization of pyrrole in lignocellulose aerogel specimens. A β-FeOOH scaffold produced via thermal hydrolysis provided ample space for the growth of polypyrrole (PPy), and PPy along with TPs improved the flame retardancy and thermoelectric performance of the aerogel. A comparison with pristine wood showed that the heat release rate and total heat release of TPLA were 69.43 % and 72.60 % lower, respectively. The limiting oxygen index of TPLA was substantially higher by 20.48 %, and the UL-94 flame retardant rating was upgraded to V-0. The Seebeck coefficient of the TPLA reached 23.88 μV·K^-1 at 298 K, and this generated a potential difference of >100 mV upon encountering fires, showing that the material has good fire alarm properties. Thus, TPLA is promising for the development of smart fire alarm systems with satisfactory fire retardancy.