Polyimide benzene

In 1988 Heinze and Burton reported a facile synthesis of various a,p,P-trifluorostyrenes.15 These trifluorostyrene compounds were reported to be unstable to cyclodimerization at room temperature when stored neat, especially the compounds that were /lura-substituted with electron-donating substituents. They described the preparation of one compound, l,4-bis(trifluorovinyl)benzene with the observation that the material gelled when allowed to stand neat overnight. They offered the explanation that the gel was a polymer network connected with flnorinated cyclobutanes. Burton later went on to utilize this dimerization reaction for the cross-linking of polyimide thermoplastics.16... 

Thermal stability. The presence of side chains, cross-linking, and benzene rings in the polymer s "backbone increase the melting temperatures. For example, a spectrum of polymers with increasing melting temperatures would be polyethylene, polypropylene, polystyrene, nylon, and polyimide. 

Polyetherimides (PEI) are polyimides containing sufficient ether as well as other flexibi-lizing structural units to impart melt processability by conventional techniques, such as injection molding and extrusion. The commercially available PEI (trade name Ultem) is the polymer synthesized by nucleophilic aromatic substitution between 1,3-bis(4-nitrophthalimido) benzene and the disodium salt of bisphenol A (Eq. 2-209) [Clagett, 1986]. This is the same reaction as that used to synthesize polyethersulfones and polyetherketones (Eq. 2-206) except that nitrite ion is displaced instead of halide. Polymerization is carried out at 80-130°C in a polar solvent (NMP, DMAC). It is also possible to synthesize the same polymer by using the diamine-dianhydride reaction. Everything being equal (cost and availability of pure reactants), the nucleophilic substitution reaction is probably the preferred route due to the more moderate reaction conditions. 

The key to acetylene terminated polyimides is the availability of the end-capper which carries the acetylene group. Hergenrother (130) published a series of ATI resins based on 4-ethynylphthalic anhydride as endcapping agent. This approach first requires the synthesis of an amine-terminated amide acid prepolymer, by reacting 1 mole of tetracarboxylic dianhydride with 2 moles of diamine, which subsequently is endcapped with 4-ethynylphthalic anhydride. The imide oligomer is finally obtained via chemical cyclodehydration. The properties of the ATI resin prepared via this route are not too different from those prepared from 3-ethynylaniline as an endcapper. When l,3-bis(3-aminophenox)benzene was used as diamine, the prepolymer is completely soluble in DMAc or NMP at room temperature, whereas 4,4 -methylene dianiline and 4,4 -oxydianiline based ATIs were only partially soluble. The chemical structure of ATIs based on 4-ethynylphthalic anhydride endcapper is shown in Fig. 45. 

Aromatic polyimides have many anisotropic imide rings and benzene rings, and they are easy to orient by a film-forming process. Molecular orientation in polyimide films causes in-plane/out-of-plane birefringence (AnJ. Russell et al. have reported the A/ / of conventional PMDA/ODA. On the other hand, spin-coated polyimide films just after preparation do not cause Ann, as noted in the... 

Properties of the polyimides based on 3,5-diaminodiphenyl ether and l-amino-3-phenoxy-5-(4-aminophenoxy)-benzene are given in Table 5.4. Comparison of the polyimides obtained using different methods does not permit a conclusion to be reached as to which method is preferable - in almost all cases high molecular weight polyimides were obtained. 

Polyimides based on l-amino-3-phenoxy-5-(4-aminophenoxy)-benzene and snch dianhydrides as dianhydride of diphenyloxide-3,3 4,4 -tetracarboxylic acid, dianhydride A and dianhydride 6F are soluble in NMP, dimethylformamide (DMF), w-cresol, THF and chloroform. The polyimide based on benzophenone-3,3, 4,4 -tetracarboxylic acid dianhydride is partially soluble in w-cresol and NMP it is insoluble in chloroform, THF and DMF. Polypyromellitimide is insoluble in all the solvents tested. 

Oxidative homocoupling of aromatic and heteroaromatic rings proceeds with Pd(OAc)2 in AcOH. Biphenyl (165) is prepared by the oxidative coupling of benzene [104,105], The reaction is accelerated by the addition of perchloric acid. Biphenyl-tetracarboxylic acid (169), used for polyimide synthesis, is produced from dimethyl phthalate (168) commercially [106], Intramolecular coupling of the indole rings 170 is useful for the synthesis of staurosporine aglycone 171 [107]. 

Hydrosilylation of BMI with l,4-bis(dimethylsilyl)benzene leads to the formation of polysiloxane polyimide [69]. 

As an approach to a better understanding of adhesion mechanisms between polyimide and copper, we have studied the interaction between a set of model molecules for a polyimide and vapor deposited polycrystalline copper. Thin films and adsorbates of benzene, phthalimide, methyl-phthalimide, benzene-phthalimide, and malonamid, which are representative of separate parts of the polyimide repeat unit, were deposited in situ on clean copper and examined by means of X-ray and Ultraviolet photoelectron spectroscopy (XPS and UPS). In contrast to the previously observed bonding to the carbonyl oxygen in polyimide, as Cu is deposited on polyimide, our results show that most of these polyimide model molecules bond to Cu, through electron transfer, with the imide nitrogen atom as the primary reaction site. 

The results are based on measurements using the following polyimide model molecules Benzene (BE), phthalimide (PIM), methyl-phthalimide (MPIM), benzene-phthalimide (BPIM), and malonamide (MAM). The geometrical structure of these model molecules and, for comparsion, a polyimide (PI) of the type PMDA/0DA, are shown in Figure 1. 

In this study, we have used a set of polyimide model molecules to obtain information about possible interactions at the polyimide copper interface. Benzene, phthalimide (PIM), benzene-phthalimide (BPIM), methyl-phthalimide (MPIM), and malonamid (MAM) were deposited in ultrahigh vacuum (UHV) onto clean polycrystalline copper substrates, and the measurements were performed by means of XPS and UPS. 

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. 

The polyimide pictured is a step-growth polymer of a benzene tetracarboxylie acid and an aromatic diamine. 

Soluble all-aromatic polyimides have been produced by coupling hexafluoropropane-(6F) and oxygen-(ODPA) containing dianhydrides with oxydianiline and bis(aminophenoxy)benzene diamines. 

A multilayer film of obtained as above was immersed overnight in a mixture of acetic anhydride, pyridine, and benzene (1 1 3) to afford a polyimide film of 5a.(1)... 

According to literary data, the following mixtures of aromatic/aliphatic-aromatic hydrocarbons were separated toluene/ n-hexane, toluene/n-heptane, toluene/n-octane, toluene/f-octane, benzene/w-hexane, benzene/w-heptane, benzene/toluene, and styrene/ethylbenzene [10,82,83,109-129]. As membrane media, various polymers were used polyetherurethane, poly-esterurethane, polyetherimide, sulfonyl-containing polyimide, ionicaUy cross-linked copolymers of methyl, ethyl, n-butyl acrylate with acrilic acid. For example, when a composite polyetherimide-based membrane was used to separate a toluene (50 wt%)/n-octane mixture, the flux Q of 10 kg pm/m h and the separation factor of 70 were achieved [121]. When a composite mebrane based on sulfonyl-containing polyimide was used to separate a toluene (1 wt%)/ -octane mixture, the flux 2 of 1.1 kg pm/m h and the separation factor of 155 were achieved [10]. When a composite membrane based on ionically cross-linked copolymers of methyl, ethyl, w-butyl acrylate with acrilic acid was used to separate toluene (50 wt%)//-octane mixture, the flux Q of 20-1000 kg pm/m h and the separation factor of 2.5-13 were achieved [126,127]. 

To increase the sorption component of the separation factor, homogeneously distributed tetracyanoethylene, a strong electron acceptor having high affinity for electron donors, was added to the polyimide matrix [77]. It can be seen from data presented in Table 9.12 that this is accompanied by an increase in the sorption component /3s (benzene/cyclohexane) by a factor of 1.5 probably as a result of selective sorption of aromatic compounds by tetracyanoethylene with a simultaneous increase in the diffusion component /3d. The prepared membranes showed good pervaporation properties with respect to benzene/cyclohexane, toluene/isooctane mixtures. For example, for a two-component 50/50 wt% benzene/cyclohexane mixture at 343 K, the flux was 2 = 0.44 kg p,m/m h, and /3p (benzene/cyclohexane) = 48 and for a two-component toluene/isooctane mixture, 45/55 wt%, at 343 K the flux was 2 = 1-1 kg p-m/m h, and /3p (toluene/wo-octane) = 330. 

FIGURE 9.28 Dependence of productivity for the mixture (o) and separation factor of benzene/cyclohexane j3p(x) on degree of phosphorylation for phosphorylated and thermally cross-linked BPDA-TrMPD polyimides henzene/cyclohexane, 50/50 wt% mixture, r=343 K, membrane thickness 30-40 p-m. (From analysis of data presented in Semenova, S.I., J. Membr. Sci., 231, 189, 2004. With permission.)... 

Ethynyi Groups According to Ref. [77], acetylene fragments introduced into polyimides, e.g., 2,2 -diethynylbenzidine, DEB, have TT-electron affinity for aromatic compounds. It can be seen from the data presented in Table 9.12 that the increase in the content of DEB component results in an increase in the separation factor of the benzene/cyclohexane mixture. This is probably caused not only by the growth of the diffusion component /8d (resulting from thermal cross-linking through the unsaturated bonds) but also by enhancement of the sorption component /Ss-... 

Wang YC, Li CL, Huang J, Lin C, Lee KR, Liaw DJ, and Lai JY. Pervaporation of benzene/cyclohexane mixtures through aromatic polyimide membranes. J Membr Sci 2001 185 193-200. 

Bis(3-aminophenyl)arylene ethers are useful monomers to prepare polyimides of lower Tg s. For example, l,3-bis(3-aminophenoxy)benzene has been used as building blocks for various thermally processable PI systems. The compound was originaly synthesized by Fink [6] according to the following Ullmann synthesis under rather harsh conditions. 

Figure 1. Infrared spectra (KBr) of (A) polyimide prepared by photolysis of benzene sobitions of ii,N -hexarnethylenebistnaleirnide (B) polyimi prepared from benzene-maleic anhydride photoadauct (2) and 1,6-hexanediamine and (C) the N,N -bis(n-...

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