Environmentally Friendly Flame-Retardant and Its Application in Rigid Polyurethane Foam

Figure 7

Digital images of char residue after cone calorimeter test: (a) neat PU, (b) DPTP (2 phr), (d) DPTP (5 phr), (e) DPTP (8 phr), and (f) DPTP (10 phr).

(a)

(b)

(c)

(d)

(e)