BPDA-ODA polyimide

Rimdusit, S. Benjapan, W. Assabumrungrat, S. Takeichi, T. Yokota, R., Surface Segregation of Siloxane Containing Component in Polysiloxane-Block-Polyimide and s-BPDA/ODA Polyimide Blends. Polym. Eng. Sci. 2007,47, 489-498. 

Oxidation Most posttreatment processes arc used to alter the pore size distribution in the CMS membrane. The most common method used to increase the pore size in CMS membranes is low-temperature oxidation. Researchers have used several different techniques. Softer et al. (1987) treated hollow-fiber CMS membranes derived from cellulose precursors using 400°C air for 15 min to increase the permeance. Kusakabe et al. (1998) produced supported CMS membranes from BPDA-ODA polyimide. The membranes were then posttreated with oxygen at 300°C for 3 h. The posttreatment increased the permeance by an order of magiutude but had tittle effect on the selectivity. The authors attributed this to an increase in pore volume without broadening the pore size distribution. 

The thermal imidization of a polyamic acid film (PMDA-ODA or BPDA-ODA) obtained by casting an NMP solution leads to an amorphous polyimide. Two different teams have shown that a polyamic acid solutions in NMP heated at 200°C for a short time (20 min) gives polyimide particles fully cyclized and highly crystalline, as shown by X-ray diffraction and solid 13C NMR spectroscopy.151152 The chemical imidization of the same solution gives only amorphous particles. The difference between the cyclization of a solution and a casted film in the same solvent is intriguing. In the case of the solution, the temperature and the heating time are lower than in the case of the casted film as a consequence, a less organized structure would be expected for the particle. 

J. Hayashi, H. Mizuta, M. Yamamoto, K. Kusakabe and S. Morooka, Pore Size Control of Carbonized BPDA-pp ODA Polyimide Membrane by Chemical Vapor Deposition of Carbon, J. Membr. Sci. 124, 243 (1997). 

Hayashi, J., Mizuta, H., Yamamoto, M., Kusakabe, K. and Morooka, S. (1996) Separation of ethane/ethylene and propane/propylene systems with a carbonizad BPDA-pp ODA polyimide membrana. Industrial el Engineering Chemistry Research, 35, 4176. 

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. 

Hayashi J, Mizuta H, Yamamoto M, Kusakabe K, Morooka S, Suh SH. Separation of ethane/ethylene and propane/pro-pylene systems with a carboniz BPDA-pp ODA polyimide membrane. Ind Eng Chem Res 1996 35 4176-4181. 

Hayashi J, Yamamoto M, Kusakabe K, MorookaS (1997) Effect of oxidation on gas permeation of carbon molecular sieve membranes based on BPDA-pp /ODA polyimide. Ind Eng Chem Res 36 (6) 2134-2140... 

Another family of aromatic polyimides is produced from the condensation reaction between biphenyl tetra carboxylic dianhydride (BPDA) and aromatic diamines such as ODA and p-phenylene diamine, PDA. The polyimides BPDA-ODA and BPDA-PDA are available from Ube Industries under the Upilex R and S trademarks, respectively. Their T s are reported to be >400°C. Structures appear in Fig. 1.29. 

Recently two other trifluoromethyl-containing monomers have been introduced—OBABTF and DABTF—that have been shown to decrease the dielectric constant and moisture absorption.Polyimides made from OBABTF had a lower dielectric constant than materials made from the unfluorinated analogue ODA in every case with PMDA, BPDA, and ODPA. 

Relative to microelectronic applications, the out-of-plane dielectric constant for BPDA-PFMB films measmed after aging at 50% relative humidity for 48 h at 23°C was between 2.8 and 2.9 (0.1 kHz to 1 MHz) (ASTM D-150-81These values are considerably lower than that of commercial polyimides such as PMDA-ODA (pyromellitic dianhydride, PMDA) (s = 3.5 at 1 kHz and 3.3 at 10 MHz). The dielectric constant and tan 8 (dissipation factor) were temperature- and frequency-dependent. The dielectric constant, which was independent of temperature until near 210°C increased above this point until a frequency-dependent maximum was reached at about 290°C. The dissipation factor, which was also independent of temperatme below 200°C, underwent a rapid increase with no maximum between 200 and 400°C owing to ion conductivity. The temperatme at which this increase occurred increased as the frequency increased. The films also... 

With ultra violet sources (He I) the entire valence band could not be obtained (29,58). Interestingly, the two polyimides, PMDA-ODA and BPDA-PDA which showed such distinctly different core-level spectra (Figure 6) show quite similar valence-band spectra (Figure 11) with only subtle differences. Figure 12 and Figure 13 show the cross-section modulation for polyamic acid on Cu and Cr. Detailed analysis of these spectra will lead to further understanding of the polymer-metal interaction. 

Methods. Polyamic acid in NMP was spin-coated onto a Si or Quartz wafer (diameter = 2.25 inches) coated with Cr, and then cured to polyimide at 400 °C. The purpose of the 500-750-A-thick layer of chromium is to enhance wettability and to give good reflectance to the Quartz wafer. Kapton H (PMDA-ODA) and Upilex S (BPDA-PDA) films were employed for gravimetric analysis. Around 5-um thick layers were used to measure the thickness change. The 100-1000-A-thick layers were employed to obtain XPS and ER IR spectra. The samples for contact angle measurement, XPS and ER IR were dried under vacuum at ambient temperature for 12-24 h and the samples for gravimetric analysis were dried at 85 °C for 12 h. The samples for film thickness measurement were fully re-cured to polyimide. 

Starting materials and solvents were purchased from Aldrich Chemical Co. acetonitrile (ACN), N,N-dimethylformamide (DMF), and N-methyl-2-pyrrolidone (NMP) were obtained anhydrous in Sure/Seal bottles and used as received. The polyamic acid of PMDA-ODA (2545 Pyralin) was supplied by DuPont. The soluble polyimide XU-218, derived from 3,3, 4,4 -benzophenone tetracarboxylic dianhydride (BTDA) and diamino-1,1,3-trimethyl-3-phenylindan isomers (DAPI) was purchased from Ciba-Geigy Corp. The acetylene terminated imide oligomer powder (Thermid MC-600) derived from BTDA, aminophenylacetylene, and 1,3-bis (2-aminophenoxy) benzene (APB) was obtained from National Starch and Chemical Company. Kapton Type II (PMDA-ODA) films were obtained from DuPont Co., Apical polyimide films were obtained from Allied Corp., and Upilex Type-S and Type-R polyimide films derived from 3,3, 4,4 -biphenyl tetracarboxylic dianhydride (BPDA) plus p-phenylenediamine (PDA) and ODA, respectively were obtained from ICI Americas Inc. 

---