Naphthalene-Based Poly (Ether-Amide)S Bearing Metylene Linkage To Enhance Processability

Abstract

New  diacid monomer   4,4'- (1,5-Naphthalenedioxy)dibenzoicacid(III) was prepared through reaction of  1,5-naphthol   followed by 4-fluoroacetophenone to  4,4'-(1,5-Naphthalenedioxy) diacetyl(I)  followed by Conrad  Willgerodt reaction with Kindler variation using sulphur and morpholine formed  4,4'-(1,5-Naphthalenedioxy) thioacetomorpholide (II) further, new diacid (III) monomer was obtained by base catalyzed hydrolysis of intermediate thiomorpholide in ethanol. The structure of diacid was confirmed by ¹H NMR, ¹³C NMR, FT-IR and Mass Spectra. A new series of poly(ether-amide)s were synthesized by using direct Yamazaki’s phosphorylativepolycondensation method from new diacid (III) monomer with different commercial diamines such as  4,4’-diamino diphenyl ether (ODA), diaminodiphenyl methane (MDA), 4 amino phenyl sulfone , P-phenylenediamine M-phenylenediamine.  Inherent viscosities of these poly(ether-amide)s were in the range 0.35 to 0.81 dL/g indicating moderate molecular weight built-up. These poly(ether-amide)s exhibited excellent solubility in various polar aprotic solvent such as N-methyl pyrrolidone (NMP), N, N-dimethyl sulphoxide (DMSO), N, N-dimethyl acetamide (DMAc) N,N-dimethyl form amide (DMF) etc. All these poly(ether-amide)s were showed good solubility in pyridine and they partial solubility in common solvent such as THF, DCM. The initial decomposition temp (Ti) of synthesized poly(ether-amide)s were  in the range   396ºC to 420 ºC. The 10% weight loss was in the range491º to 516ºC. The char yield of these poly(ether-amide)s  were in the range  45.26 to 59.26 % at 800 ºC. X-ray diffraction pattern showed that in corporation of methyl substituent on aromatic backbone and naphthyl moiety containing ether linkage and methylene spacer would disturb the chain regularity and packing, leading to amorphous nature. The structure-property relationship of naphthyl containingpoly(ether-amide)s  was studied in the view of  potential applications of these  polymer  as thermally stable and processable high performance polymers.