Synthesis And Characterization Of Novel Aromatic Polyamides?Polyimides And Poly (Aryl Ether Ketone)s Containing Pyridine Unit And Triphenylphosphine Pendant Groups

In the dissertation, the recent progress on the study of polyamides, polyimides and poly(aryl ether ketone)s were introduced. This paper was mainly composed of three parts as follow.1. 4-(Diphenylphosphino)-benzaldehyde was prepared by triphenylphosphine and 4-bromobenzaldehyde. Then the treatment of 4-(diphenylphosphino)-benzaldehy--de with 4-nitroacetophenone through a modified Chichibabin reaction obtained 4-(4'-diphenylphosphino)phenyl-2,6-bis(4'-nitrophenyl) pyridine(DPPPBNPP), which was reduced into a new kind of the novel diamine containing a heterocyclic pyridine substitute and triphenylphoranylidene pendant group, 4-(4'-diphenylphosphino) phenyl-2, 6-bis(4'-amniophenyl)pyridine(DPPPBAPP) with Pa/C and hydrazine monohydrate. The new diamine(DPPPBAPP) was used to prepare several aromatic polyamide bearing pyridine and triphenylphosphine moieties via low-temperature polymerization with four different alkane-dioyl dichlorides containing isophthaloyl chloride(IPC), terephthaloyl chloride(TPC), etc. The inherent viscosities(?inh) of the synthesized polymers were ranging from 0.50 to 0.93 d L/g. These polymers were soluble in dipolar solvents at room temperature such as N-methyl-2-pyrrolidone, dimethyl formamide, N, N'-dimethylacetamide and partly soluble in chloroform. All polymers were amorphous, and exhibited glass transition temperatures in range of 317–383 oC, the temperatures of 5 % weight loss in range of 458–505 oC, the temperatures of 10 % weight loss in rang of 482– 554 oC, and the residual weight in range of 63-71 % in argon. In addition, all the PAs films exhibited good mechanical properties with tensile strengths in range of 60–80 MPa, elongations at break in range of 4.95–7.75 %, and tensile modulus in range of 1.09–2.31 GPa, which suggested that these new PAs could be considered as new potential engineering plastics. All films were transparent with more than 86 % of transmittance at 800 nm light-wavelength, and the cutoff wavelength in range of 380-395 nm.2. A series of aromatic polyimides were achieved with the diamine(DPPPBAPP) and different aromatic dianhydrides, such as ODPA(a), 6FDA(b), BPDA(c) and BTDP(d), via the conventional two-step method, involving ring-opening polycondensation forming the poly(amic acid)s(PAAs) and further imidization forming polyimides. The chemical imidization of PAA-a and PAA-b by dehydrating obtained soluble PI-a and PI-b with inherent viscosities of 0.35 and 0.38 d L/g, which dissolved both in aprotic organic solvents, such as NMP, DMF, DMAc, DMSO, and in common solvents, such as THF and CHCl3. Other polyimdes using thermal imidization achieved insoluble PI-c and PI-d, which the inherent viscosities of corresponding poly(amic acid)s were 0.51 and 0.49 dL/g. Besides, PI-c and PI-d films had a tensile strength of 65 and 81 MPa, a Young's modulus of 1.2 and 1.9 GPa. Two polymers exhibited low optical transparency, only 71% and 53% of transparence at 800 nm light-wavelength. In addition, all the polyimides behaviored excellent thermal properties with high glass transition temperature(Tg) in range of 300-380 oC, and the decomposition temperature( at 5 % weight loss) of above 517 oC.3.A new kind of pyridine-bridged and triphenylphosphine substituents aromatic bisphenol monomer, 4-(4'-diphenylphosphino)phenyl-2, 6-bis(4'-hydroxyph--enyl) pyridine(DPPPBHPP), was successfully synthesized by a modified Chichibabin reaction of 4-(diphenylphosphino)-benzaldehyde with p-hydroxyaceoph--enone. Then, The bisphenol(DPPPBHPP) was employed to synthese a series of new poly(aryl ether ketone)s with pyridine-triphenylphosphine by the high-temperature solution polycondensation with various bisfluoro compounds, which included 4, 4'–difluorobenzophenone; 1, 3-bis(4-fluorobenzoyl)benzene; 4, 4'-bis(4-fluorobenz--oyl)biphenyl and 4, 4'-bis(4-fluorobenzoyl)diphenyl ether. Their inherent viscosities ranged from 0.30 to 0.53 d L/g, and nearly all of the polymers were readily soluble in commom organic solvents sunch as NMP ? DMSO ? DMF ? THF and CH2Cl2. Meanwhile, these polymers were amorphous and maintained outstanding thermal stability with glass transition temperature up to 220 oC. Among them, PEK-a and PEK-b showed high thermal-decomposition temperatures at 383 oC and 353 oC, respectively. And 10 % weight loss temperatures in Ar2 were above 440 oC.