Study on synthesis and properties of poly(aryl ether ketone imide) having bis(o-methyl) pendent groups

Three novel monomers were synthesized and confirmed by FT-IR and H-1-NMR. N, N'-(4,4'-diphenyl-methane) bistrimellitimide diacid chloride (DIDC-M) was synthesized by acidylated the 4,4'-bis( N-Trimellitimide)diphenylmethane, which obtained from trimellitic anhydride with 4,4'-diaminodiphenylmethane (DDM) .2,2', 6,6'-Tetremethyl-4, 4'-diphenoxy diphenylketone (o-Me-2-DPOBP) and 2, 2', 6, 6'-tetremethyl-4, 4'-diphenoxy-triphenyldiketone (o-Me-2-DPOTPDK) were prepared by aromatic nucleophilic substitution reaction by 2, 6-dimethylphenol with 4 14'-difluorodiphenylketone and 4, 4'-difluorotriphenyldiketone respectively at the presence of sodium hydroxide, using DMSO as solvent at 200 degrees C. Two novel poly(aryl ether ketone imide) copolymers containing his(o-methyl) moieties were prepared by low temperature solution polycondensation of DIDC-M with o-Me-2-DPOBP or o-Me-2-DPOTPDK in 1,2-dichloroethane (DCE) and at the presence of AICl(3) and N-methyl-2-pyrrolidone (NMP) as catalyst. The structure of copolymers (P-a , P-b) obtained were characterized by FTIR and H-1-NMR. Differential scanning calorimetry (DSC) analysis indicated that the copolymers showed high glass transition temperature (T-g) 240 degrees C and 237 degrees C, respectively. The single T-g' s in the DSC cures suggested that no microphase separation occurred in the block copolymer. The copolymer also showed a high thermal stability with 5% weight-loss temperatures in excess of 464 degrees C in nitrogen, while 10% weight-loss temperature over 513 degrees C, according to thermogravimetric analysis (TG). Wide-angle X-ray diffraction (WAXD) studies revealed that P. and Pb were amorphous, which agreed with the results of DSC, and as a result of introducing the rigid imido structure or non-planar methyl pendent to polymer backbone, the regularity of macromolecular chain destroyed. The soluble behaviours of the copolymers were tested qualitatively at room temperature in common organic solvents. It showed that the copolymers have good solubility in the following solvents. N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), NMP, dichloromethane, tetrechloroethane and chloroform. Flexible and colorless films were easily obtained by solution casting with DMAc as solvent. Tensile strength, elongation at break and Young's module of P-a were 80.0 MPa, 6.95 %, and 2.0 GPa respectively, and for P-b were 51.8 MPa, 4.6 %, and 1.8 GPa, respectively. So introducing methyl pendent groups in the polymer main chain and copolymerization with novel monomers are efficient methods to synthesis high performance advanced materials. Furthermore, the copolymers contain methyl pendant group as a potential functional group, which can be converted into aldehyde or carboxylic acid, so it provides an original way to prepare functional PI/PEK copolymer's.