Cardanol derived P, Si and N based precursors to develop flame retardant phenolic foam

Abstract

A novel eco-friendly halogen-free cardanol-based flame retardant with P, Si, and N on the chain backbone (PSNCFR) was synthesized and incorporated into phenolic foams (PFs). PSNCFR was comprehensively investigated via Fourier transform infrared spectroscopy and nuclear magnetic resonance. PSNCFR endowed PFs with flame retardancy, contributed to generating a composite char defense against flames, and efficiently prevented smoking from PFs. PSNCFR introduction improved the flexural strength of the PFs to approximately 155% of that of pristine PF. PSNCFR-modified PFs displayed a high limiting oxygen index value of 41.9%. The results of cone calorimeter show that the mean heat release rate, mean effective heat of combustion, and total heat release of the PSNCFRmodified PFs reduced by 26.92%, 35.71%, and 31.25%, respectively. In particular, the total smoke production of the PSNCFR-modified PFs decreased by 64.55%, indicating excellent smoke inhibition. As for the mechanism, the condensation and gas phases during pyrolysis were responsible for the synergistic flame retardancy in the modified PFs. The findings demonstrate that PSNCFR can be used in PF preparation to overcome their drawbacks of internal brittleness and flammability.

A Thermoset Shape Memory Polymer-Based Syntactic Foam with Flame Retardancy and 3D Printability

“…The C 1s spectrum peaks are centered at 284.5, 286.6, and 288.7 eV, which could be assigned to C–C and C–H of the aliphatic and aromatic species, C–O group, and C=O group, respectively. 52 In Figure S6 (K1 HGM syntactic foam char), one C 1s peak has been observed at 282.5 eV, which may be attributed to the Si–C group. 52 , 60 The O 1s spectrum shows two peaks at 531.1 and 532.5 eV, in which the first one may be related to the P=O or C=O groups and the second one may be assigned to C–O–C groups, respectively.…”

“… 52 In Figure S6 (K1 HGM syntactic foam char), one C 1s peak has been observed at 282.5 eV, which may be attributed to the Si–C group. 52 , 60 The O 1s spectrum shows two peaks at 531.1 and 532.5 eV, in which the first one may be related to the P=O or C=O groups and the second one may be assigned to C–O–C groups, respectively. 52 In the case of K1 foam char, only one peak at 531.7 eV has been noticed.…”

“…61 The P 2p spectrum has two peaks at around 133.3 eV (P=O) and 134.2 eV (P=N). 52 , 62 In addition, the peaks in Si 2p spectra at 105.6 and 106.2 eV may be attributed to the silicone oxides structures. 63 On the basis of these findings and the SEM images, it is evident that when the syntactic foams are ignited, the thermally stable isocyanurate and phosphine oxide structures mostly contribute to the formation of the char of the syntactic foam.…”

“… 52 , 60 The O 1s spectrum shows two peaks at 531.1 and 532.5 eV, in which the first one may be related to the P=O or C=O groups and the second one may be assigned to C–O–C groups, respectively. 52 In the case of K1 foam char, only one peak at 531.7 eV has been noticed. The N 1s spectrum displays that the bind energy attributed to the stable C–N bond in the six-membered ring in isocyanurate species and the N–P bond in the char residue to be 400.5 and 398.6 eV, respectively.…”

Progress in Bio‐Based Phenolic Foams: Synthesis, Properties, and Applications

“…In addition, the modification provides high smoke inhibition. Total smoke production (TSP) calculated from the cone calorimetry studies showed a 64.5 % decrease [149].…”