Study Of Synthesis And Property Of Diketone Polyimide And Copolyimides Based On TDPA

Polyimide(PI) is a special polymer materials that the main chain containing imide ring, It showed that plugging agent have heat resistance, radiation hardenung, low dielectric constant, good chemical stability, good insulation, good mechanical property, size and oxidation stability and other excellent performance. It's one of the best materials in the overall performance of synthetic material. It has great application and development prospects in aerospace, military equipment, microelectronics industry and other high technology. The variety and molecular structure aromatic dianhydride and aromatic diamine determines the structure, performance and value of polyimide materials. High production cost, notched impact sensitive, poor hydrolysis resistance and poor working performance is PI material common problems and improve performance through structural modification of PI materials. Development of new applications PI has been a hot and difficult topic PI materials research.Ketones anhydride PI because of its mature processing technology and excellent performance has been widely used, has become benzene, ether anhydride, fluorine anhydride PI outside another major new varieties PI. Because of its structure keto polarity, the single-ketone anhydride PI having very good interface properties with carbon fiber, glass fiber and copper and other metallic material. Ketone anhydride PI has been widely used composite matrix resin, adhesive, magnetic paint, printed circuit boards and supersonic aircraft, rockets, jet engine parts and other areas.Research of diketone anhydride PI began in the 1970 s, 1970 a French Patent and an European patent in 1985 s relates to a process for preparing diketone anhydride. NASA create diketone anhydride 4,4'-isophthaloyldiphthalic anhydride(IDPA) PI applications, which the trade name is Larc-I-TPI by IDPA and m-phenylenediamine with two-step process, at room temperature Ti /Ti tensile shear strength of single lap 18.5MPa, 204? and 232?, tensile shear strength respectively 22.9MPa and 20.8MPa, has been used in high-temperature adhesives, high temperature composite laminates and electrical insulating paint materials and other products.4,4'-isophthaloyldiphthalic anhydride(TDPA) is isomers to IDPA, diketone anhydride TDPA PI is rare in literature. Diketone anhydride PI most commonly used for the synthesis of two-step process. The first step by the diketone dianhydride and aromatic diamine condensation at low temperature to obtain a polyamide acid(PAA), the second step is imidization by thermal or chemical imidization cyclodehydration. Thermal imidization can be divided into solid-phase thermal imidization and solution imidization hot, solid-phase thermal imidization PI films used in the preparation of upcoming film PAA salivation after heating to imidization. Thermal imidization is added to a solution of PAA solution in an azeotropic solvent, heating under reflux, the solvent out of the water by azeotropic generated during imidization, promoting further imidization reaction. PAA due to poor storage stability of the first step of the synthesis, high thermal imidization temperature required PI too rigid and thermally imidized after molding difficult. PI powder obtained by chemical imidization, but the chemical imidization process is easy polyisoimide polyimide, and the resulting lower PI orderliness, thereby affecting PI macroscopic properties. Therefore, to find a more reasonable PI synthesis pathway is important. In general, the adhesive its physical form, can be divided into solution form, pasty, film-like, and so on. Which has a uniform thickness film-like adhesive, glue content is accurate, simple construction techniques can be used for large area bonding, etc., especially for bonding honeycomb sandwich structure, with several other forms unmatched adhesion advantage.Based on the relationship between structure and properties of polymer-based TDPA, four double ketone synthesis anhydride type PI, and were characterized by their structure and properties. The main contents are as follows:(1) Synthesis and properties of thermoplastic diketone anhydride polyimideStudy found that the introduction of semi-flexible chain units in PI molecular chain, such as an ether group, ketone group, it can reduce the melting temperature of PI, improve impact toughness, improve the processing performance. Diketone structure makes anhydride polyimide resin and carbon fiber, glass fiber reinforced material having an excellent interfacial smear, can be applied as an advanced composite material and the adhesive matrix resin. This paper is based on diketone anhydride TDPA and diamine 3,3'-(4-aminophenoxy)benzophenone(BABP) and m-phenylenediamine(MPD) were prepared by two-step diketone anhydride polyimide(DK-PI), by the polyamic acid(DK-PAA) to determine the optimum reaction logarithmic ratio of a reduced viscosity measured to TDPA overshooting or phthalic anhydride(PA) polyamic acid(DK-PAA) were terminated, compared the effects of capping agent for DK-PI thermodynamic properties. Were treated with thermal imidization and chemical imidization of PI films and powders were prepared to study the effects of two methods iminated DK-PI performance. By Fourier transform infrared spectroscopy(FT-IR), wide-angle X-ray diffraction(WAXD), differential scanning calorimetry(DSC), thermal gravimetric analysis(TGA), tensile testing, water absorption tests and performance tests on polymers dissolved the structure and properties were characterized. DK-PI is a degree of thermoplastic polyimide can be used as advanced composite matrix resins and adhesives, aerospace and other high techonoly fields have important applications.(2)Synthesis and Properties of diketone anhydride copolyimideThis article will introduce flexible PI keto group the main chain, reducing the intermolecular forces, leading to the glass transition temperature decreases, lowering PI melting temperature, in order to improve impact toughness, improve the processing properties; also pyromellitic anhydride structures exist and ensure its good thermal stability. In homemade TDPA as a third monomer, with PMDA and 3,3'-(4-aminophenoxy)benzophenone(BABP), 4,4'- diaminodiphenyl methane(MDA) by the two-step method prepared by co-condensation of two copolyimide(Copolyimide, CPI), using Fourier transform infrared spectroscopy(FT-IR), wide-angle X-ray diffraction(WAXD), differential scanning calorimetry(DSC), thermal gravimetric analysis(TGA), tensile testing, water absorption test, and solubility tests on the structure and properties of polymers were characterized investigated mole ratio of the CPI influence the performance of PMDA/TDPA monomer.