Polyether-polyamide

A wide range of polyether-polyamide block copolymers were first offered by Atochem in 1981 under the trade name Pebax. These are made by first producing a low molecular weight polyamide using an excess of dicarboxylic acid at a temperature above 230°C and under a pressure of up to 25 bar. This is then combined with a polyether by reaction at 230-280°C under vacuum (O.l-lOTorr) in the presence of a suitable catalyst such as Ti(OR)4. 

Table 18.16 Selected properties of polyether-polyamide block copolymers of the Pebax type (After Deleens, 1987)...

Recent work on the synthesis, structure and some properties of macromolecules bearing furan rings is discussed. Two basic sources of monomers are considered, viz. furfural for monomers apt to undergo chain polymerization and hydroxymethylfurfural for monomers suitable for step polymerization.Within the first context, free radical, catiomc and anionic systems are reviewed and the peculiarities arising from the presence of furan moieties in the monomer and/or the polymer examined in detail. As for the second context, the polymers considered are polyesters, polyethers, polyamides and polyurethanes. Finally, the chemical modification of aU these oligomers, polymers and copolymers is envisaged on the basis of the unique reactivity of the furan heterocycle. 

Frost74) in Union Carbide Corporation also prepared polyether-polyamide membranes containing free carboxyl groups (24). The salt rejection of the membrane, however, was relatively low (46% for 3.5% NaCl aqueous solution at 70kg/cm2), although pure water flowed at 143 1/m2 day. 

In contrast, organophilic PV membranes are used for removal of (volatile) organic compounds from aqueous solutions. They are typically made of rubbery polymers (elastomers). Cross-linked silicone rubber (PDMS) is the state-of-the-art for the selective barrier [1, 43, 44]. Nevertheless, glassy polymers (e.g., substituted polyacetylene or poly(l-(trimethylsilyl)-l-propyne, PTMSP) were also observed to be preferentially permeable for organics from water. Polyether-polyamide block-copolymers, combining permeable hydrophilic and stabilizing hydrophobic domains within one material, are also successfully used as a selective barrier. 

The membrane material is decisive for the removal efficiency. Urkiaga et al. [129] tested different commercially available membranes on their adsorption characteristics for MTBE showing that sihcone rubber was more efficient than polyether-polyamide block-copolymer membranes (PEBA) and polyoctyl methyl siloxane membranes (POMS) at MTBE concentrations of 250mg/L and 1250 mg/L. The studies by Keller et al. [128] and Vane et al. [130] used polypropylene and silicone rubber membranes, respectively. 

In addition, carboxylic esters, ethers, amides, urethanes, and sulfones are implicitly permitted because polyesters, polyethers, polyamides, polyurethanes, and polysulfones are among the types of polymers allowed under the exemption, as long as these functional groups have not been modified to enhance their reactivity. One such group that would not be allowed is the dinitrophenyl ester of a carboxyhc acid, which is far more reactive due to the activating functionality ... 

Louie JS, Pinnau I, Ciobanu I, Ishida KP, Ng A, and Reinhard M, Effects of polyether-polyamide block copolymer coating on performance and fouling of reverse osmosis membranes, Journal of Membrane Science 2006, 280, 762-770. 

Polyether-polyamide block copolymers have been found to meet these criteria very fine precipitates in the region of 0.5 to 2.0 xm have been observed. 

Low-temperature process Production of relatively pure CO2 stream Both chemical and physical absorption are mature technologies Commercial polymeric membranes are available (polyimide, polysulfone, polyether-polyamide copolymer, etc.) and can be used with an adsorption liquid (e.g. MEA)... 

Permanent antistats do not depend on the relative humidity and they do not lose their effectiveness in a short time. One type is exemplified by the use of polyether-polyamide block copolymers combined with an intrinsically conducting substance, and another class consists of neoalkoxytitanates or zirconates. These compounds form non-blooming, bipolar layers, producing a surface and volume electron-transfer circuit, which produces a permanent antistatic effect. They are independent of atmospheric moisture and compatible with a wide range of polymers, including polyolefins, polyesters, polystyrene and PVC. Inherently conducting polymer additives such as sulfonated polyanilines are also used. They are discussed further in Chapter 5. 

Mass spectrometry experiments in general, and MALDI-TOF in particular, require the sample to be in the gas phase and ionized. Ionization is commonly achieved by the complexation of a cation with the polymer molecule. Polymers containing heteroatoms such as polyethers, polyamides, polyesters, polymethyl-metacrylates, polysiloxanes, and polycarbonates are reasonably simple to be cationized by the addition of sodium or potassium salts. Apolar polymers containing double bonds such as polyst5Tene, polybutadiene, and polyisoprene can also... 

Block copolymer systems have aroused interest with reviews of the synthesis of nylon elastomers, thermoplastic polyether-polyamide elastomers, and thermoplastic cross-linked polyamides of 3,3 -bis(hydroxymelhyl) glutaric add. Block copolymers were also reported from poly(/n-phenylene isophthalamidc) and poly(ethylene oxide) or poly(dimethylsiloxane). The polycondensation of oco -dicarboxylic-poly(amide 11) and x -dihydroxy-polyoxyethylene has also been studied and rate constants and activation energies evaluated for the process. The polycondensation of axo -diacid and e9o> -diester-poly(amide 11) oligomers with cuco -dihydroxy-polyether oligomers has similarly been reported. Lactam Rli -opening Polymerization Routes.—The effects of ring size, substitution and the presence of heteroatoms on the polymerizability of lactams has been the subject of reviews. - In the field of lactam polymerization, two systems have evoked major interest, namely caprolactam and 2-pyrrolidone. Studies on caprolactam have reported the effect of water on the mechanism of polymerization and polymerization rate, where it was found that the process was... 

This type of SEC-MS hyphenation has been applied to a wide variety of homopolymers and copolymers amongst them are polyacrylates, polyesters, polyethers, polyamides, resins, polycarbonates, proteins, and polystyrene. Synthesis optimization, investigation of the degradation behavior of polymers, polymer aging, and deformulation have been the goals of the analysis. 

Warwel et al. applied catalytic methods of olefin chemistry to achieve polymer building blocks as well as polymers like functionalized polyolefins, polyesters, polyethers, polyamides as well as sugar-based surfactants [4]. The fundamental approach was the polymer synthesis based on unsaturated fatty acid methyl esters, which are available by industrially applied transesterification of fats and oils with methanol. In Figure 18 is reported a schematic representation of the potential of plant oil components in the preparation of different polymeric materials. 

Gas permeation through a polymer membrane is not only a function of the chemical structure of the polymer chains, but is also determined by a morphology inside the film with typical domain dimensions of several nanometers. Membranes from commercial polyether- -polyamide (PEBA) polymers with varying chemical composition, cast from both n-butanol and cyclohexanol are studied by SAXS, in dry form and water-swollen, and as a function of strain. The nanostructure from soft and hard domains is determined [681. 

Yoko F and Chiaki T (1983) Stabilizers for polyester-polyether-polyamide rubbers, JP Patent 60 053,558, to Toray Ind., Chem Ahstr 103 143217. 

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