Novel polyarylates containing aryl ether units: synthesis, characterization and properties

Abstract

To improve the processability of the poly(p‐hydroxybenzoic acid), copolyarylates containing m‐aryl ether units were synthesized using p‐acetoxybenzoic acid, 1,4‐diacetoxybenzene and 1,3‐bis(4'‐carboxyphenoxy)benzene by melt transesterification reaction. The structure and properties of these polyarylates were characterized using infrared spectra, differential scanning calorimetry, thermogravimetric analyses, wide‐angle X‐ray diffraction and polarized optical microscopy etc. The results showed that all polyarylates were semicrystalline materials and could form a thermotropic liquid crystalline intermediate state. As the content of aryl ether units increased, the crystallization and melting temperatures of the polyarylate decreased; meanwhile, the crystalline ability became lower. The introduction of the aryl ether could restrain the formation of a liquid crystalline structure and reduce the thermal stability to some extent. After solid state polymerization (SSP), the intrinsic viscosity, melting temperature, crystallinity and thermal stability of the polyarylate increased while the melting range narrowed. However, the SSP reaction might be accompanied by degradation and crosslinking.

Novel poly(ether ketone)arylates: Synthesis, characterization and properties

“…HQ, m ‐dihydroxybenzene, potassium carbonate, N ‐methyl‐2‐pyrrolidone (NMP), 4‐hydroxybenzoic acid, toluene, ethanol, acetic anhydride, sulfuric acid, p ‐hydroxybenzoic acid (PHBA), zinc acetate, diantimony trioxide, dimethyl sulfoxide (DMSO) (all from Chengdu Ke Long Co.), and 4,4′‐difluorobenzophenone (DFBP, from Wuhan XinHuayuan chemical Co.) were analytically pure and used as received. 1,3‐bis(4′‐carboxylphenoxy)benzene [PMP(COOH) 2 ] was prepared in our laboratory and the synthesis route was reported by our previous work 20…”

“…In our previous work,20 in order to reduce the melting temperature of TLCP with reserving thermotropic liquid crystalline state, a series of liquid crystalline copolyarylates containing m ‐aryl ether units were synthesized using p ‐acetoxybenzoic acid (PABA), 1,4‐diacetoxybenzebe (DAB), and 1,3‐bis(4′‐carboxyphenoxy)benzene [PMP(COOH) 2 ] by melt transesterification reaction. We considered blending those liquid crystalline copolyarylates with poly(ether ether ketone) (PEEK) to reduce the melt viscosity and improve the processability of PEEK.…”

Effect of thermotropic liquid crystalline poly(ether ketone)arylates on the processibility and properties of poly(ether ether ketone)s fibers

“…It was found that the addition of TLCP significantly reduced the melting viscosity of PEEK, especially at a shear rate of 118 s −1 ; the mechanical properties were improved when the content of TLCP exceeded 10 wt %. In previous works of our group, we synthesized a thermotropic liquid crystalline polyarylate (PEAR) and applied it in facilitating the processibility of PEEK and polyphenylene sulfide . However, both Vectra 950A and PEAR were incompatible or semicompatible with PEEK; as a result, the composites could not achieve the best mechanical properties as we expected.…”

“…In previous works of our group, we synthesized a thermotropic liquid crystalline polyarylate (PEAR) and applied it in facilitating the processibility of PEEK and polyphenylene sulfide. [18][19][20] However, both Vectra 950A and PEAR were incompatible or semicompatible with PEEK; as a result, the composites could not achieve the best mechanical properties as we expected. It is worthwhile to find a kind of TLCP that is compatible with PEEK to improve the processibility and mechanical properties of PEEK simultaneously.…”

Synthesis and characterization of thermotropic liquid crystalline polyarylate with ether ether ketone segments in the main chain

“…This is because Vectra has poor compatibility with PEEK. Our previous works have reported two modification strategies to modify TLCPs for improving the compatibility between PEEK and TLCP . However, the synthesized TLCPs and PEEK are just partially compatible, so they are not highly effective processing agent for PEEK.…”