Yaming Niu

Synthesis and Properties of Poly(aryl ether ketone) Copolymers Containing 2,7-Naphthalene Moieties

Poly(aryl ether ketone) copolymers containing 2, 7-naphthylene and hydroquinone (HQ) moieties with various compositions were prepared by the reaction of 4,4′-difluorobenzophenone (DFB) 2,7-naphthylene and hydroquinone in the presence of sodium carbonate and potassium carbonate (19: 1, mass ratio) in diphenyl sulfone (DPS). The thermal analysis results of the copolymers show that the glass transition temperatures (Tgs) increase, while the melting temperatures (Tm) and the 5.0% weight loss temperatures (Td) decrease with the increase of the 2,7-naphthalene moieties. For the copolymers synthesized at a molar fraction of 2,7-naphthalene in the difluoro monomers being over 0. 30, no peaks corresponding to the cold crystallization temperature and the melting temperature could be detected, indicating that these copolymers are almost amorphous. The crystal structures of the copolymers with a molar fraction of 2,7-naphthalene being less than 0. 30 are rhombic.

New Poly(aryl ether ketone) Copolymers Containing 1,5‐Napthalene Rings

A new monomer 1,5‐bis(4‐(4′‐fluorobenzoyl) phenoxy) naphthalene(1,5‐BFPN) was synthesized with 4,4′‐difluorobenzophenone(DFB) and 1,5‐dihydroxynaphthalene(DHN), and the new monomer was characterized by X‐Ray single crystal diffraction. The polycondensation of 1,5‐BFPN with PEEK oligomer in diphenyl sulfone (DPS) in the presence of an excess of sodium carbonate and potassium carbonate as a condensation reagent was carried out at 320°C to quantitatively afford the corresponding poly(ether ether ketone‐co‐ether naphthalene ether ketone) regular copolymers. Thermal analysis of the copolymers showed that the glass transition temperature increased, while the melting temperature decreased with increasing the content of 1,5‐BFPN moieties.

Synthesis and Properties of Poly(Aryl Ether Ketone) Copolymers Containing 1,4‐Naphthalene Moieties

Abstract The new monomer 1,4‐bis (4‐fluorobenzoyl) naphthalene was synthesized using the Friedel–Crafts acylation reaction of 1,4‐naphthalenedicarboxylic acid chloride with fluorobenzene. Poly(aryl ether ketone) copolymers possessing various compositions of 1,4‐naphthylene and 1,4‐phenylene moieties were prepared by the reaction of hydroquinone (HQ) with 1,4‐bis(4,4′‐fluorobenzoyl) naphthalene (1,4‐BFN) and 4,4′‐difluorobenzophenone (DFB) in the presence of sodium carbonate and potassium carbonate in diphenyl sulfone (DPS). Thermal analyses of the copolymers showed that the glass transition temperature increased, while the melting temperature and 5 wt% loss temperature decreased with the increase of 1,4‐naphthalene moieties. For the copolymer synthesized with the molar fraction of 1,4‐BFN in the difluoro monomers (1,4‐BFN, DFB) being over 0.1, no cold crystallization temperature and melting temperature were detected, indicating that these copolymers are almost amorphous. The crystal structure of the copolymers with the molar fraction of 1,4‐BFN, not being higher than 0.4, is rhombic. The poly(aryl ether ketone)s copolymers were soluble in polar aprotic solvents step by step for the molar fraction of 1,4‐BFN being over 0.4.

Synthesis and Characterization of Poly(ether ether ketone)s with (2,5‐dihydroxy)phenyl Side Group

A new monomer, (2,5‐dimethoxy)phenylhydroquinone (DMPH), was prepared in a two‐step synthetic procedure. One aromatic poly(ether ether ketone)s with 2,5‐dimethoxy phenyl side group (DMP‐PEEK) was synthesized via an aromatic nucleophilic substitution reaction with 4,4′‐difluorobenzophenone (DFB). Poly(ether ether ketone)s with 2,5‐dihydroxy phenyl side group (DHP‐PEEK) was obtained via hydrolysis of methoxy group on the DMP‐PEEK. Both of the high molecular weight polymers could be obtained despite the steric effect of the bulky pendant groups. The two polymers have good solubility at room temperature.

Synthesis and Properties of Poly(Aryl Ether Ketone) Copolymers with Trifluoromethyl‐Substituted Benzene in the Side Chain

The new monomer (4‐(4′‐trifluoromethyl)phenoxyphenyl)hydroquinone (TFPOPH) was synthesized in a three‐step synthesis. A series of poly(aryl ether ketone) copolymers were prepared by the reaction of (4‐(4′‐Trifluoromethyl)phenoxyphenyl)hydroquinone and hydroquinone (HQ) with 4,4′‐difluorobenzophenone (DFB) in the presence of potassium carbonate in tretramethylene sulfone (TMS). Thermal analyses of the fluorinated copolymers showed that the glass transition temperature and 5.0% weight loss temperature are similar with that of PEEK, and the crystallinity decreased with increasing of TFPOPH. For the copolymer synthesized with the molar fraction of TFPOPH in the diphenol monomers (TFPOPH, HQ) being over 0.2, no cold crystallization temperature and melting temperature were detected, indicating that these copolymers are almost amorphous. The crystal structure of the copolymers with the molar fraction of TFPOPH being not higher than 0.2 is rhombic. The solubility in polar aprotic solvents of poly(aryl ether ketone)s copolymers increases and dielectric constant decreases step by step.