A novel thermotropic liquid crystalline copolyester containing phosphorus and aromatic ether moity toward high flame retardancy and low mesophase temperature

Abstract

A series of thermotropic liquid crystalline polyesters containing phosphorus and aromatic ether groups (TLCP‐AEs) were synthesized from p‐acetoxybenzoic acid (p‐ABA), terephthalic acid (TPA), 4,4′‐oxybis(benzoic acid) (OBBA), and acetylated 2‐(6‐oxid‐6H‐dibenz(c,e) (1,2) oxaphosphorin 6‐yl) 1,4‐benzenediol (DOPO‐AHQ). The chemical structure and the properties of TLCP‐AEs were characterized by Fourier‐transform spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), differential scanning calorimetry (DSC), X‐ray diffraction (XRD), thermogravimetry analysis (TGA), scanning electronic microscopy (SEM), polarizing optical microscopy (POM), limiting oxygen index, and UL‐94 tests, respectively. The results showed that TLCP‐AEs had low and broad mesophase temperatures (230–400 °C). TLCP‐AEs also showed excellent thermal stability; their 5%‐weight‐loss temperatures were above 440 °C and the char yields at 700 °C were higher than 45 wt %. All TLCP‐AE polyesters exhibited high flame retardancy with a LOI value of higher than 70 and UL‐94 V‐0 rating. The SEM observation revealed that TLCP‐AEs had good fibrillation ability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1182–1189, 2010

Phosphorus‐Containing Polymer Flame Retardants for Aliphatic Polyesters

“…Addition of polymeric phosphorus‐containing FRs provides a better incorporation into the polymer matrix and avoids leaching. A number of phosphorus‐containing polymers with varied chemical structure have been developed and proposed as FR additives for polyesters. Most of these polymers contain 9,10‐dihydro‐9‐oxy‐10‐phosphaphenanthrene‐10‐oxide (DOPO) substituents attached to the polyester main chain.…”

Improved antiplatelet therapy? There's a generic thought

“…The concept of achieving thermal stability, flame retardancy, and liquid crystalline behavior through combination of phosphorus‐containing monomers and aliphatic moieties into aromatic mesogenic moieties was successfully applied for the control of thermal stability, phase transitions, and crystallinity degree of aromatic–aliphatic phosphorus‐containing copolyesters 29, 31–33. Recently, Wang and coworkers have paid attention to the use of phosphorus‐containing TLC polymers for flame retardation on other thermoplastic polymers 34–36. Thermal stability and flame retardancy of these polymers were excellent, but the mesophase and melting temperatures need to be more decreased.…”

Liquid-Crystal and Fire-Retardant Properties of New Hexasubstituted Cyclotriphosphazene Compounds with Two Schiff Base Linking Units

“…Moreover, the LOI values of the alkylated compounds were lower compared to those of compounds with the hydroxy, carboxy, and amino groups at the terminal end. The longer the alkyl tails are attached to the cyclotriphosphazene ring, the more combustible the target materials [53,54].…”