Oxydianiline and pyromellitic

The kinetics of PAA, synthesized from 4,4 -oxydianiline and pyromellitic dianhydride, solid-state imidization both in filler absence and with addition of 2 phr Na+-montmorillonite was studied [1], The nanofiller was treated by solution of P-phenylenediamine in HC1 and then washed by de-ionized water to ensure a complete removal of chloride ions. The conversion (imidization) degree Q was determined as a function of reaction duration t with the aid of Fourier transformation of IR-spectra bands 726 and 1014 cm 1. The samples for FTIR study were obtained by spin-coating of PAA/Na+-montmorillonite mixture solution in N,N-dimethylacetamide on KBr disks, which then were dried in vacuum for 48 h at 303 K. It was shown, that the used in paper [1] method gives exfoliated nanocomposites. The other details of nanocomposites polyimid/Na+-montmorillonite synthesis and study in paper [1] were adduced. The solid-state imidization process was made at four temperatures 7) 423, 473, 503 and 523 K. 

DuPont uses oxydianiline and pyromellitic dianhydride (Fig. 3.42) to produce a series of Kapton films (Table 3.46), Vespel sintered moldings (Table 3.47), and Pyralin lacquers... 

The first patent of Edwards and Robinson147 claims the condensations of pyromel-litic acid and aliphatic diamine salt to prepare polyimide. Recently, that approach has been revisited, and biphenyl tetracarboxylic and pyromellitic acids give a salt monomer by reaction with 1 mol of an aliphatic diamine (octamethylene diamine and dodecamethylene diamine). The salts were polymerized under 250 MPa at 250°C for 5 h in closed reaction vessels (Fig. 5.32) giving crystalline polymers.148 By reaction of pyromellitic tetraacid with oxydianiline, it has been possible to isolate a monomeric salt. It was polymerized under 30 MPa giving a PMDA-ODA polyimide with water elimination. 

Hedrick et al. reported imide aryl ether ketone segmented block copolymers.228 The block copolymers were prepared via a two-step process. Both a bisphenol-A-based amorphous block and a semicrystalline block were prepared from a soluble and amorphous ketimine precursor. The blocks of poly(arylene ether ether ketone) oligomers with Mn range of 6000-12,000 g/mol were coreacted with 4,4,-oxydianiline (ODA) and pyromellitic dianhydride (PMDA) diethyl ester diacyl chloride in NMP in the presence of A - me thy 1 morphi 1 i nc. Clear films with high moduli by solution casting and followed by curing were obtained. Multiphase morphologies were observed in both cases. 

Further work in this area is underway employing polyamic acid systems which are known to produce higher viscosity solutions (e.g. polyimides derived from 4,4 -oxydianiline and either BTDA or pyromellitic dianhydride). This is being carried out in the belief that higher viscosity solutions will give rise to higher quality, less brittle films and will, thereby, enable a broader spectrum of metal systems to be studied regarding the adhesive and electrical conductance properties of metal ion filled polyimides. 

An all aromatic polyetherimide is made by Du Pont from reaction of pyromellitic dianhydride and 4,4,-oxydianiline and is sold as Kapton. It possesses excellent thermal stability, mechanical characteristics, and electrical properties, as indicated in Table 3. The high heat-deflection temperature of the resin limits its processibility. Kapton is available as general-purpose film and used in applications such as washers and gaskets. Often the resin is not used directly rather, the more tractable polyamide acid intermediate is applied in solution to a surface and then is thermally imidized as the solvent evaporates. 

IR spectroscopy may be used to follow two reactions occurring in polyimides exposed to high temperatures and humidities hydrolysis of the imide linkages and hydrolysis of residual anhydride end groups. The hydrolytic susceptibilities of several polyimides were measured at 90°C/95% R.H. Polymers based on benzophenone tetracarboxylic acid dianhydride (with either oxydianiline or m-phenylene diamine) appeared to undergo rather rapid hydrolysis initially, but the reaction had essentially halted by the time the measured imide content had decreased by 5-6%. Polymers based on 3,3 ,4,4 -biphenyl tetracarboxylic acid dianhydride (with p-phenylene diamine) and pyromellitic dianhydride (with oxydianiline) showed no significant imide hydrolysis. In all the polymers, the anhydride was hydrolyzed quite readily. 

Oxydianiline was separately mixed with 2,6-diaminopyridine and 3,5-diamino-1,2,4-triazole, to form a mixture of diamines. Then poly-(imide)s (PI)s were synthesized by reacting the mixture of the diamines and pyromellitic dianhydride. The adhesion strength of sputter-deposited copper to PI films is proportional to the content of functional groups." ... 

In 2003, Yang et al. first reported the method of carbon fiber preparation by carbonizing the electrospun PI fibers (Yang et al, 2003). They discussed the parameters for the PI electrospinning, pointing out the proper concentrations and viscosity of the solutions, as well as the voltage and electric field. Their job provided precious experience for the followup works. In their work, 4,4 -oxydianiline (ODA) and pyromellitic dianhydride (PMDA)... 

Fig. 33.6 fhe polyimide structures of (a) BTDA-ODA (3.3. 4,4 -benzophenonetctracarboxylic dianhydride 4,4 -oxydiani-line), (b) PMDA-ODA (pyromellitic dianhydride 4.4 -oxydianiline). and (c) 6FDA-ODA (2.2-bis(.3.4-dicarboxyphenyl)hex-atluoropropane dianhydride 4,4 -oxydianilinel. 

Cu-BTC (Figure 5b) was spun into MMM hollow fibers with a polyimide prepared from 4,4-oxydianiline (ODA) and pyromellitic dianhydride (PMDA). Hydrogen, H2 permeance, and selectivity of H2 with respect to N2, CO2, O2, and CH4 increased with increased Cu-BTC loading. At 6 wt% Cu-BTC, the permeance of H2 was higher by 45%, and its ideal selectivity from other gases was up by a factor of 2-3 compared to pure polyimide. 

Thianthrene-2,3,7,8-tetracarboxylic anhydride polymerized with aromatic diamines by the conventional low temperature technique to yield soluble poly(amic acid)s. Polyimides were obtained by thermal cyclization of poly(amic add) films. Rigid diamines gave brittle films whereas 4,4 -oxydianiline and 4,4-methylene dianiline gave films that were creasable. The polyimides had excellent thermal stability in nitrogen and air and a moderate increase in solubility over the more linear and rigid analogs obtained firom pyromellitic dianhydride. 

The polyimide is formed by the thermal polycyclocondensation of the poly(amide acid). For this purpose, 5 ml of poly(amide acid) solution are placed on a watch glass (diameter 10 cm) and kept in a vacuum oven at 50 °C for 24 h.The solvent evaporates and at the same time cyclization to the polyimide takes place the resulting film is insoluble in dimethylformamide.The formation of the polyimide can be followed by IR spectroscopy the NH-band at 3250 cm disappears while imide bands appear at 1775 and 720 cm" Once the initial drying process has raised the solid content to 65-75%, the polyimide formation can be accelerated by heating the poly(amide acid) film to 300 °C in a vacuum oven for about 45 min.The polyimide made from pyromellitic dianhydride and 4,4 -oxydianiline exhibits long-term stability in air above 200 °C. 

Aromatic polyimides have excellent thermal stability in addition to their good electrical properties, light weight, flexibility, and easy processability. The first aromatic polyimide film (Kapton, produced by DuPont) was commercialized in the 1960s and has been developed for various aerospace applications. The structure of a typical polyimide PMDA/ODA prepared from pyromellitic dianhydride (PMDA) and 4,4 -oxydianiline (ODA), which has the same structure as Kapton, is shown in (1). Aromatic polyimides have excellent thermal stability because they consist of aromatic and imide rings. 

The two-step poly(amic acid) process is the most commonly practiced procedure. In this process, a dianhydride and a diamine react at ambient temperature in a dipolar aprotic solvent such as N,N- dimethyl acetamide [127-19-5] (DMAc) or N-methylpyrrolidinone [872-50 4] (NMP) to form apoly(amic acid), which is then cyclized into the polyimide product. The reaction of pyromellitic dianhydride [26265-89 4] (PMDA) and 4,4 -oxydianiline [101-80-4] (ODA) proceeds rapidly at room temperature to form a viscous solution of poly(amic acid) (5), which is an ortho-carboxylated aromatic polyamide. 

However, a second component shifted to higher binding energy was observed for thin films of the compound adsorbed onto aluminum that had been cleaned by ion bombardment and then exposed to oxygen. Finally, Linde [18] has suggested that polyamic acids of pyromellitic dianhydride and oxydianiline do not react with films formed by y-APS adsorbed onto metal substrates such as aluminum and chromium because the silane is adsorbed through the amino groups. 

Abstract—The effects of both y-aminopropyltriethoxysilane (APS) and elevated temperature and humidity (T H) exposure on the adhesion of pyromellitic dianhydride-oxydianiline polyimide to SiO , AkOi, and MgO were studied using XPS, SEM, and peel test. Adhesion and T H stability of PMDA-ODA on Si02 is significantly improved when APS is used at the interface, while no significant improvement is observed for AkO, or MgO. XPS analysis of the surfaces showed no retention of APS on AkO, or MgO, while Si02 did retain APS, as is expected. The APS retention is affected by surface treatment of the oxide prior to APS application. 

Adhesion of polyimides to inorganic substrates is of great importance to the microelectronics industry [1, 2]. The polyimide films are deposited most often by spin coating the polyamic acid (PAA) usually from a TV-methylpyrrolidone (NMP) solution onto the substrate surface followed by thermal imidization at temperatures up to 400<>C. The most studied polyimide is the pyromellitic dianhydride-oxydianiline (PMDA-ODA), which exhibits excellent mechanical and dielectric properties, but not so good adhesion characteristics. The latter has been generally overcome by application of an adhesion promoter, such as y-aminopropyltriethoxysilane [3-7]. The reactions of APS (coated from water solution) with the silicon dioxide surface as well as with polyamic acid have been well characterized by Linde and Gleason [4] however, we do not have such detailed information available on APS interaction with other ceramic surfaces. 

Polyimide surface modification by a wet chemical process is described. Poly(pyromellitic dianhydride-oxydianiline) (PMDA-ODA) and poly(bisphenyl dianhydride-para-phenylenediamine) (BPDA-PDA) polyimide film surfaces are initially modified with KOH aqueous solution. These modified surfaces are further treated with aqueous HC1 solution to protonate the ionic molecules. Modified surfaces are identified with X-ray photoelectron spectroscopy (XPS), external reflectance infrared (ER IR) spectroscopy, gravimetric analysis, contact angle and thickness measurement. Initial reaction with KOH transforms the polyimide surface to a potassium polyamate surface. The reaction of the polyamate surface with HC1 yields a polyamic acid surface. Upon curing the modified surface, the starting polyimide surface is produced. The depth of modification, which is measured by a method using an absorbance-thickness relationship established with ellipsometry and ER IR, is controlled by the KOH reaction temperature and the reaction time. Surface topography and film thickness can be maintained while a strong polyimide-polyimide adhesion is achieved. Relationship between surface structure and adhesion is discussed. 

Polyimides have excellent dielectric strength and a low dielectric constant, but in certain electrolyte solutions they can electrochemically transport electronic and ionic charge. Haushalter and Krause (5) first reported that Kapton polyimide films derived from 1,2,4,5-pyromellitic dianhydride (PMDA) and 4,4 -oxydianiline (ODA) undergo reversible reduction/oxidation (redox) reactions in electrolyte solutions. Mazur et al., (6) presented a detailed study of the electrochemical properties of chemically imidized aromatic PMDA- derived polyimides and model compounds in nonaqueous solutions. Thin films of thermally... 

One commonly used polyimide is poly(N,N -bis(phenoxyphenyl)-pyromellitimide). This may be prepared from the reaction of pyromellitic dianhydride (PMDA) and oxydianiline (ODA) in a two step process (Figure 1). The first step involves a solution reaction forming the poly(amic acid) (PAA). After solvent removal this material can be thermally cyclized to the polyimide (PI). To improve properties, it is often annealed at temperatures up to 400° C. 

Systems that employed HREELS for interfacial-composition determinations included poly(ethylene oxide)-polystyrene diblock copolymer on Si wafers formaldehyde poly(oxymethylene) films on Cu(lOO) and Lang-muir-Blodgett films of 4,4 -oxydianiline-pyromellitic dianhydride polyimide on Au and on highly ordered pyrolytic graphite. ... 

Poly(imides) contain the group -C(0)-NH-C(0)- in their structure. Many poly(imides) with practical applications have a more complicated formula and contain oxygen atoms and aromatic rings in the backbone [1]. One example is poly(pyromellitic dianhydride-a/f-4,4 -oxydianiline) or PMDA-ODA, CAS 25038-81-7, which is obtained from pyromellitic anhydride and oxybis(benzenamine) by water elimination as follows ... 

Fluorescence spectra of polyimide as a function of thermal history for two of the most common commercially available polyimide precursors, Du Pont PI-2545 and PI-2555, were obtained. These precursors are polyamic acids formed from the polycondensation reaction of pyromellitic dianhydride (PMDA) and oxydianiline (ODA),... 

The polyamic acids were prepared in these laboratories using modifications of a standard preparation (7). Benzophenone tetracarboxylic acid dianhydride (BTDA), benzenetetracarboxylic acid dianhydride (pyromellitic dianhydride PMDA), oxydianiline (ODA), 1,4-phenylenediamine (PDA) and 1,3-phenylenediamine (MPDA) were all obtained from Aldrich Chemical Co. The S -biphenyl tetracarboxylic acid dianhydride (BPDA) was obtained from Ube Chemical Company. The polyamic acids were prepared in N-methylpyrrolidinone (BTDA-ODA, BTDA-MPDA and BTDA with a 1 1 molar ratio of MPDA and ODA) or dimethyl acetamide (BPDA-PDA and PMDA-ODA). 

Synthesis and Characterization of the f-Butyl Ester of the Oxydianiline—Pyromellitic Dianhydride Polyamic Acid... 

Novel f-butyl esters of oxydianiline/pyromellitic dianhydride polyamic acid were prepared in good yield. The polymers were prepared with either meta or para repeating units. The cure behavior of these f-butyl esters was studied by IR, MS and TG analysis and was compared to that of both the parent polyamic acid and its methyl ester. It was found that a rapid deprotection of the f-butyl group occurs at around 200°C with liberation of free polyamic acid. Consequently, the cure behavior at 200 C of the f-butyl ester approaches that of the parent polyamic acid. Furthermore, the isomerism of the repeating units does not appear to have any detectable effect on the cure behavior of the polymer, although, meta isomerism appears to enhance solubility of the polymer in organic solvents. 

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