新型含吡啶环芳香二胺及其可溶性聚酰亚胺的合成与表征

Soluble polyimide based on a novel pyridine-containing aromatic diamine

以苯甲醛和3-(4-硝基苯氧基)苯乙酮(NPAP)为原料,通过改进的Chichibabin反应制备了硝基化合物4-苯基-2,6-双[3-(4-硝基苯氧基)苯基]吡啶(PNPP),再用Pd/C和水合肼将PNPP进行还原,成功制备了一种新型含吡啶环的芳香二胺4-苯基-2,6-双[3-(4-胺基苯氧基)苯基]吡啶(PAPP)。以PAPP作为二胺,3,3′,4,4′-二苯醚四羧酸二酐(ODPA)作为二酐,N,N-二甲基甲酰胺(DMF)为溶剂,通过常规的两步法,经热或者化学亚胺化形成聚酰亚胺,制得了一种新型的含吡啶环聚酰亚胺。所得聚酰胺酸和聚酰亚胺的粘度分别为0.59 dL/g和0.56 dL/g。化学亚胺化所得的聚酰亚胺速溶于常见有机溶剂如DMF、N,N-二甲基乙酰胺(DMAc)、N-甲基-2-吡咯烷酮(NMP)、四氢呋喃(THF)等。制得了柔韧的聚酰亚胺膜,膜有很好的热稳定性,玻璃化转变温度(T_g)为230.8℃,氮气氛中10%失重温度为552.0℃,同时,膜还有较好的力学性能,拉伸强度为88.6 MPa,拉伸模量为1.04 GPa,断裂伸长率为8.7%,膜的吸水率为0.89%。

A novel pyridine-containing aromatic diamine monomer, 4-phenyl-2,6-bis [ 3-（4-aminophenoxy） phenyl] pyridine （PAPP）, was successfully synthesized by a modified Chichibabin reaction of benzaldehyde and a substituted acetophenone, 3- （ 4-nitrophenoxy ） acetophenone （ NPAP ）, followed by a reduction of the resulting dinitro compound 4-phenyl-2,6-bis[3-（4-nitrophenoxy） phenyl] pyridine （PNPP） with Pd/C and hydrazine monohydrate. The aromatic diamine was employed to synthesize a new pyridine-containing polyimide by polycondensation with 4,4′-Oxydiphthalic dianhydride （ODPA） in N, N-dimethyllformamide （DMF） via the conventional two-step method, and further thermal or chemical imidization forming polyimide. The inherent viscosities of the resulting poly （ amic acid） and polyimide were 0.59 dL/g and 0.56 dL/g, and the polyimide obtained by chemical imidization was readily soluble in common organic solvents such as DMF , N, N-dimethylacetamide （DMAc）, N-methyl-2-pyrrolidone （NMP）, and tetrahydrofuran （THF）, etc. Meanwhile, strong and flexible polyimide film was obtained, which had good thermal stability, with the glass transition temperature （ Tg ） of 230.8 ℃ and the temperature at 10% weight loss of 552.0 ℃ in nitrogen atmosphere, as well as outstanding mechanical properties with tensile strengths of 88.6 MPa,a tensile modulus of 1.04 GPa and elongations at break of 8.7%. The polyimide film also was found to possess low water uptake of 0.89%.