Synergistic effect of Ni-based bimetallic catalyst with intumescent flame retardant on flame retardancy and thermal stability of polypropylene

Synergistic improvement of fire retardancy and mechanical properties of ferrocene‐based polymer in intumescent polypropylene composite

“…Although there is no observable intumescent char residue obtained for both PP6 and PP7, the surface of char layer is unbroken, flat, and dense. This result is attributed to three reasons: (a) PDPFDE decomposes to produce Fe n+ at the early stage after ignition; (b) these Fe n+ further catalyze the thermal decomposition of APP to produce PPA, then they are dehydrated from the PER and themselves to obtain more residual char; (c) Moreover, the produced Fe n+ may participate in the cross‐linking reaction of PPA and oxidized PP molecules in the form of bridged bond, leading to a higher melt viscosity during combustion . The lower fluidity of polymer melt is not beneficial to wrap the volatile products to form swelling carbonization layer, but just form compact char layer.…”

“…The peak at 1631 cm −1 represents the characteristic stretching vibration of C═C from polyaromatic structure . The peak at 1400 cm −1 means the characteristic peak of P─N structure . The peak at 1260 cm −1 is assigned to the characteristic peak of O groups, and 1167 and 492 cm −1 are the characteristic peaks of P─O─C structure, and 998 cm −1 is the characteristic peak of P─O─P structure .…”

“…The peak at 1400 cm −1 means the characteristic peak of P─N structure . The peak at 1260 cm −1 is assigned to the characteristic peak of O groups, and 1167 and 492 cm −1 are the characteristic peaks of P─O─C structure, and 998 cm −1 is the characteristic peak of P─O─P structure . To sum up, all char residues of PP5, PP6, and PP7 contain polyaromatic structure and a cross‐linked structure such as O, P─O─C, and P─O─P; in particular, the unburned saturated hydrocarbon groups (─CH 3 and ─CH 2 ─) remain.…”

“…According to the above characterization results and analysis, the possible char formation mechanism of PP/IFR/PDPFDE in the combustion process is shown in Scheme . For PP5 (Scheme a), the char formation reaction during combustion can be divided into two parts: (a) First, the APP decomposes during the heating process to produce PPA and ammonia gas; second, PPA is dehydrated with PER and itself to obtain phosphoric ester structures; and third, the phosphoric ester is thermally pyrolyzed at a higher temperature and cross‐linked to form a char layer; (b) The PP is dehydrogenated and oxidized to form C─O─OH and C─OH groups at a higher temperature. Next, the C─O─OH groups undergo a dehydroxylation radical reaction to obtain carbonyl structures; the C─OH groups are phosphorylated to form phosphoric ester structures; and due to the dehydrogenation of APP, PP is also dehydrogenated to obtain double bond structures .…”

Nanosized carbon black as synergist in PP/POE-MA/IFR system for simultaneously improving thermal, electrical and mechanical properties

“…To improve comprehensive performances of PP/IFRs system, one feasible way is to incorporate nanofillers as synergists. For example, many types of inorganic nanoparticles have been used, including clay [13,14], zeolite [15], carbon nanotube [16], graphene [17], layered double hydroxide (LDH) [18], silica [16], nano-aluminum hydroxide [19], metal oxides [20,21] and other nanofillers [22][23][24][25]. Zeng et al [14] added 2 mass% phosphoruscontaining montmorillonite (P-MMT) into PP/IFRs system (the total content of flame retardant was 25 mass%).…”