Aliphatic polymers polyimides

The radiation resistance for a series of polyimides(PI), poly(aryl ether ether ketone) (PEEK), poly(aryl ether sul-phone) (PES), bisphenol A type Udel poly(aryl sulphone) (U-PS), and a poly(aryl ester) (U-Polymer) is shown to be excellent when compared to the related aliphatic polymers. G values for the evolution of gases were lower by factors of between 0.01 and 0.001 of the G values for the corresponding aliphatic polymers. From the study of gas evolution, the order of radiation resistance to 7-irradiati(Mi is [186] ... 

S.-L. Nica, G. Hulubei, I. Stoica, G. E. loanid, and S. loan. Surface properties and blood com-patibihty of some aliphatic/aromatic polyimide blends. Polym. Eng. Sci. 53,263-272 (2013). 

Polyamide or polyimide polymers are resistant to aliphatic, aromatic, and chlorinated or fluorinated hydrocarbons as well as to many acidic and basic systems but are degraded by high-temperature caustic exposures. 

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. 

Phthalazinone, 355 synthesis of, 356 Phthalic anhydride, 101 Phthalic anhydride-glycerol reaction, 19 Physical properties. See also Barrier properties Dielectric properties Mechanical properties Molecular weight Optical properties Structure-property relationships Thermal properties of aliphatic polyesters, 40-44 of aromatic-aliphatic polyesters, 44-47 of aromatic polyesters, 47-53 of aromatic polymers, 273-274 of epoxy-phenol networks, 413-416 molecular weight and, 3 of PBT, PEN, and PTT, 44-46 of polyester-ether thermoplastic elastomers, 54 of polyesters, 32-60 of polyimides, 273-287 of polymers, 3... 

Polyimides of 6FDA and aliphatic diamines with good low temperature processing and low moisture swelling are known to be useful as hot-melt adhesives (109). Aluminum strips bonded by this polymer (177°C/172 kPa (25 psi) for 15 min) exhibited a lap-shear strength of 53 MPa (7690 psi) at room temperature and 35 MPa (5090 psi) at 100°C. The heat- and moisture-resistant 6F-containing Pis useful in electronic devices are prepared from... 

For highly polar polymers, Hs < —Hw, and the equilibrium concentration is a decreasing function of temperature. This is often found in the most hydrophilic networks, based, for example, on the aromatic amine -aliphatic diepoxide of diglycidyl ether of butane diol (DGEBD) type (Tcharkhtchi et al., 2000), or on particular polyimides (Hilaire and Verdu, 1993). 

Although rigid-rod poly(p-phenyleneterephthalamide) analogues having alkyl side chains did not contain cyclic polymers, the polycondensation of silylated m-phenylenediamine and aliphatic dicarboxyhc acid chloride afforded cyclic polyamides predominantly (Scheme 49) [187]. Furthermore, cyclic polymers were also produced in polycondensations for polyesters, poly(ether ketone)s, polyimides, and polyurethanes [183]. These examples are the products in polycondensation of AB monomers or in A2 + B2 polycondensations, but cyclization of oligomer and polymer was also confirmed in polycondensation of AB2 monomers [ 188-195] and in A2 + B3 [ 196-202] and A2 + B4 polycondensations [203-206], which afford hyperbranched polymers. 

Then the reactivity of the tetracarboxylic acid-based salt monomers was compared with that of the salts consisting of tetracarboxylic acid half diesters. The P-XPM series polyimides were prepared by the high-pressure polycondensation of salt monomers XPME derived from the aliphatic diamines and pyromellitic acid half diethyl ester (see Eq. 5, Ar=PM and R=ethyl) [20], in addition to the polymers obtained from the pyromellitic acid-based salt monomer XPMA [24] already shown in Table 1. The polycondensation of salts XPME proceeded readily under high pressure of 250 MPa at 240 °C for 15 h, even with the elimination of ethanol and water as the by-products in the closed reaction vessel, and this afforded the polyimides with inherent viscosities up to 1.6 dL/g. Therefore, the reactivity of salt monomers XPME was found to be almost comparable to that of the parent salt XPMA, and the properties of the resultant P-XPM series polyimides from XPME were the same as those obtained from salts XPMA. 

Furthermore, we have extended the high-pressure polycondensation to the synthesis of condensation polymers other than polyimides. A successful example was the high-pressure synthesis of polybenzoxazoles starting from the bis-o-aminophenol (or its hydrochloride) and aliphatic dinitriles (Eq. 8) [35]. The polycondensation readily proceeded under high pressure in a closed reaction vessel with the elimination of the by-product of ammonia (or ammonium chloride). 

Fully imidized soluble polyimides have ben prepared using monomers derived from diphenylindane and aromatic dianhydrides. Technical polymers (XU218, for instance), prepared from 1,1,3-trimethyl-diaminophenylindane and benzophenone-tetracarboxylic acid dianhydride, have been marketed over the last decade. Despite the partially aliphatic nature of polyimides containing the indane group, they show considerable retention of the thermal stability, with Tg values over 300 °C [107-110]. 

The thermoset polyimides are a family of heat-resistant polymers with acceptable properties up to 260°C (500°F). They are unaffected by dilute acids, aromatic and aliphatic hydrocarbons, esters, ethers, and alcohols but are attacked by dilute alkalies and concentrated inorganic acids. 

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]. 

The polymer materials mainly used for the membranes are glassy polymers, the first and foremost polyimides. The use of glassy polymers having a rigid ensemble of macromolecules results in high separation effectiveness. Separation effectiveness in pervaporation processes is characterized by the separation factor, /3p, which is determined by the diffusion component, /3d, and the sorption component, /3s [8,55]. Let us consider the effect of chemical composition of polymer membranes on their transport properties with respect to aromatic, alicyclic, aliphatic hydrocarbons and analyze ways to improve these properties. 

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