Thermal degradation behaviors of phosphorus–silicon synergistic flame‐retardant copolyester

Abstract

A novel phosphorus-containing poly (ethylene terephthalate) (PET) copolyester/nano-SiO 2 composite (PET-co-DDP/SiO 2 ) was synthesized by in situ polycondensation of terephthalic acid (TPA), ethylene glycol (EG), [(6-oxide-6H-dibenz[c,e] [1,2]oxaphosphorin-6-yl)-methyl]-butanedioic acid (DDP), and nano-SiO 2 . The morphology of PET nanocomposites was observed by using transmission electron microscope and scanning electron microscope. It was found that the SiO 2 nanoparticles were dispersed uniformly at nanoscale in the copolyesters with content 2 wt %. The thermal degradation behavior of PET nanocomposites was investigated by thermogravimetric analysis performed with air and nitrogen ambience. The activation energies of thermal degradation were determined using Kissinger and Flynn-Wall-Ozawa methods, respectively. The results obtained from Kissinger method showed that the activation energy was increased with the introduction of SiO 2 . Moreover, the activation energy is decreased for PET-co-DDP system in nitrogen and air. The results also indicated that the SiO 2 and DDP had synergic effect on the early decomposition and the late charring in air. Furthermore, in the PET-co-DDP/SiO 2 system, the activation energy increased when the DDP component increased. However, the opposite results were obtained when the Flynn-Wall-Ozawa method was used. That was because the Doyle approximation stands correct as the conversion degree is from 5% to 20%. The effects of SiO 2 and DDP on the PET thermal degradation were lower in nitrogen than in air.

Preparation and characterizations of inherent flame retarded polyamide 66 containing the phosphorus linking pendent group

“…Besides, organic phosphorus reacted with nitrogen‐containing compound derived from PA66 due to synergistic effect of P/N when it exposed to flaming temperature and formed macromolecular substances such as (PNO)x or (PN)x, which further consolidated the char protective layer. The char protective layer covered on the surface of the polymer matrix resisted even higher temperature, shielded the oxygen and heat transfer, interrupting the underlying polymer from attack by oxygen and radiant heat, thus played a role in supplying flame retardancy to the matrix . The condensed phase flame retardant mechanism was in accordance with the results of TGA mentioned previously.…”

Preparation and characterization of polyamide 6 fibre based on a phosphorus-containing flame retardant

“…Recently, 9,10-dihydro-10-[2,3-di(hydroxycarbonyl)propyl]-10-phosphaphenanthrene-10-oxide (DDP), a kind of DOPO derivatives, has attracted the attention of researchers due to its high reactivity, high thermal stability and its high ame retardant efficiency. [19][20][21] When DDP as monomer was incorporated into polymers, the generated copolymer exhibited good ame retardancy. Chang et al synthesized a series of ame retardant poly(ethylene terephthalate) (PET) with the introduction of DDP.…”

Synthesis of cerium phenylphosphonate and its synergistic flame retardant effect with decabromodiphenyl oxide in glass‐fiber reinforced poly(ethylene terephthalate)

“…Unfortunately, PET is easy to be ignited in air, which restricts its applications seriously, especially, in situations requesting flame retarding. Additionally, once ignited, PET could not extinguish and generate amounts of toxic byproducts, which are harmful to environment and human beings . Engineering‐used PET is usually reinforced by glass fiber in order to meet appropriate mechanical performance.…”