Synthesis and Characterization of DOPO-g-CNSL and Its Effect on the Properties of Phenolic Foams

Abstract

In order to improve the mechanical properties without reducing its flame retardancy of phenolic foams (PFs), 9, 10-dihydro-9-oxa-10phosphaphenanthrene-10-oxide (DOPO) was introduced in the structure of cashew nut shell liquid (CNSL) to improve its flame retardant, and the product of DOPO grafting CNSL (DOPO-g-CNSL) was obtained to modify phenolic resin, and to prepare DOPO-g-CNSL modified PFs (DCMPFs). The structures of DOPO-g-CNSL were verified by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (1 H-NMR). Compared with CNSL, thermal stability of DOPO-g-CNSL was decreased and Ti decreased by 3.53%, but the residual carbon (800°C) was increased by 35.05%. Compared with pure PF, the mechanical properties, toughness and flame retardancy of DCMPFs were increased when the ratio of DOPO-g-CNSL to phenol (DOPO-g-CNSL/P) was no more than 10%. With the dosage of DOPO-g-CNSL/P increased, Ti of DCMPFs was slightly increased, but the carbon residues (800°C) were almost unchanged. And the cell sizes of DCMPFs were basically the same as the pure PF. By comprehensive analysis, the suitable dosage of DOPO-g-CNSL/P was no more than 10%.

Lignin demethylation for modifying halloysite nanotubes towards robust phenolic foams with excellent thermal insulation and flame retardancy

“…Phenolic foams have found applications as insulation materials in buildings, aircrafts, tunnels and so on, which is due to their excellent resistance to flame, low-smoke emission, low-thermal conductivity, and ease of production. [1][2][3] Their [Corrections added on 14 Dec 2021, after first online publication: The order of the funders in the Funding Information section matched with Acknowledgments section.] preparation is generally divided into two steps.…”