A main‐chain phosphorus‐containing poly(trimethylene terephthalate) copolyester: synthesis, characterization, and flame retardance

Abstract

In order to improve the flame retardancy of the semi‐biobased polyester, poly(trimethylene terephthalate) (PTT), bis‐4‐carboxyphenyl phenyl phosphine oxide (BCPPO) was used as a third monomer to synthesize a novel main‐chain phosphorus‐containing copolyester, poly(trimethylene terephthalate‐co‐BCPPO)s (PTTBP), through melt polycondensation. Phosphorus analysis of the resulting polymers suggests that BCPPO has been introduced to PTT chain successfully. 1H and 31P nuclear magnetic resonance spectra further confirm the random chemical structure. The thermal behavior was investigated by differential scanning calorimetry and thermogravimetric analysis. The introduction of BCPPO to PTT lowered the melting point and crystallization ability because of the random copolymerization and the rigid structure of BCPPO, and the thermal stabilities of PTTBP were improved in air but decreased in nitrogen. Rheological investigations showed that the complex viscosities of all the samples were independent of frequency at low frequency (say lower than 100 rads), and shear thinning effect occurred at higher frequency. The cone calorimeter was used to test the fire behavior of PTTBP, and the results suggested that the novel copolyester had good flame retardance. Copyright © 2011 John Wiley & Sons, Ltd.

Phosphorus-containing poly(trimethylene terephthalate) derived from 2-(6-oxido-6H-dibenz〈c,e〉〈1,2〉oxaphosphorin-6-yl)-1,4-hydroxyethoxy phenylene: Synthesis, thermal degradation, combustion and pyrolysis behavior

“…The onset weight-loss temperature shows the same trend as was observed under nitrogen testing; the temperature increased from 337.1 • C for neat PTT to 375.8 • C for PTTEP30, consistent with increased cabonization in the presence of phosphorus. The char residue increases from 0.4% for neat PTT to 13.2% for PTTEP30, consistent with the weight-loss results presented above, but differing favorably from previously reported phosphorus-containing systems [3,4]. It is probably that the present system produces less volatile phosphorus compounds, affording it with significant benefits when compared to other phosphorus-modified polyesters.…”

“…1), together with melting point analysis. The 1 H NMR peaks at 7.0-8.3 (a) ppm is assigned to aryl groups of DOPO-HQ-HE; the peaks occurring at 4.0 (b), 3.7 (c), 3.6 (d), and 2.9 (e) ppm belong to methylene groups of DOPO-HQ-HE; the peaks at 4.5 (g) and 4.8 (f) ppm are attributed to hydroxyl groups. The melting point of DOPO-HQ-HE obtained from DSC is 153-156 • C, which is the same as reported in the literature (157-158 • C) [24], which further indicates the successful synthesis of DOPO-HQ-HE.…”

“…Unmodified PTT is a flammable thermoplastic polyester as is the case with PET and PBT [3,4], restricting its use in some fields. Because of the strict requirements fire safety in textile applications, identifying effective means of flame retarding PTT is a necessity; this is still a new area for materials development, as published reports to date have focused primarily on blending with other materials [5,6].…”

“…Because of the strict requirements fire safety in textile applications, identifying effective means of flame retarding PTT is a necessity; this is still a new area for materials development, as published reports to date have focused primarily on blending with other materials [5,6]. We have previously reported that phosphorus is an effective flame retardant for polyesters, leading a series of inherently flame-retardant PTT copolyesters [3,4]. Burning parameters of the phosphorus-containing copolyesters, including the heat release rate and total heat release, were lower than those of the control polymers, demonstrating that such an approach could contribute to product safety.…”

Structure and properties of halogen-free flame retardant and phosphorus-containing aromatic poly(1,3,4-oxadiazole)s fiber

“…They examined the possibility of using bromine-containing terephthalic acids as monomers for the preparation of re-resistance bers. 12 Bis(4-carboxyphenyl)phenyl phosphine oxide (BCPPO) is a highly efficient ame retardant containing triaryl phosphine oxide (TPO) and dicarboxy functional groups, which has been used as a third monomer to prepare many inherently ameretardant polymers, such as poly(trimethylene terephthalate), 13 poly(ethylene terephthalate), 14,15 polyarylate, 16 polyamide 66, 17 soluble aromatic copolyamides 18 etc. From these literatures, it can be found that the copolymers exhibited improved ame retardance, hydrolytic stability and thermal stability, when BCPPO was incorporated into their main chains.…”