Polyesters, ionic

Our cooperation with Sheats also extended into the area of condensation polymers of cobalticinum salts.92 Ionic polyesters were prepared by melt-phase transesterification of 1,1 bis(carbethoxy)cobalticinium hexafluorophosphate with various diols. Low molecular-weight polysters were formed. However, attempts to prepare polyamides by melt condensations of alkylene diammonium salts of l,l -bis(carboxy)cobalticinium PFg salts resulted in decomposition.92... 

Polymerization The ionic polyesters were prepared by standard high-temperature melt-condensation procedures (3). 

Calorimetry. The glass transition temperatures (Tg s) of the ionic polyesters were determined under nitrogen on a DuPont 990 thermoanalyzer. Heating and cooling rates were 10°C/min. 

Polymer I was an amorphous water-soluble polymer with an inherent viscosity of 0.33 and a Tg of 26°C. The Mn and were 6,419 and 15,546 respectively. The ionic polyester displayed excellent adhesive properties as shown in Figure 1. Absolute peel force values could not be obtained... 

Ionic polymers are also formulated from TDI and MDI (43). Poly(urethane urea) and polyurea ionomers are obtained from divalent metal salts of /)-aminohen2oic acid, MPA, dialkylene glycol, and 2,4-TDI (44). In the case of polyureas, the glycol extender is omitted. If TDI is used in coatings apphcations, it is usually converted to a derivative to lower the vapor pressure. A typical TDI prepolymer is the adduct of TDI with trimethyl olpropane (Desmodur L). Carbodiimide-modified MDI offers advantages in polyester-based systems because of improved hydrolytic stabihty (45). Moisture cure systems based on aromatic isocyanates are also available. 

Hydrophobic fibers are difficult to dye with ionic (hydrophilic) dyes. The dyes prefer to remain in the dyebath where they have a lower chemical potential. Therefore nonionic, hydrophobic dyes are used for these fibers. The exceptions to the rule are polyamide and modified polyacrylonitriles and modified polyester where the presence of a limited number of ionic groups in the polymer, or at the end of polymer chains, makes these fibers capable of being dyed by water-soluble dyes. 

Even within the small numbers of studies conducted to date, we are already seeing potentially dramatic effects. Free radical polymerization proceeds at a much faster rate and there is already evidence that both the rate of propagation and the rate of termination are effected. Whole polymerization types - such as ring-opening polymerization to esters and amides, and condensation polymerization of any type (polyamides, polyesters, for example) - have yet to be attempted in ionic liquids. This field is in its infancy and we look forward to the coming years with great anticipation. 

Room-temperature ionic liquids have received much attention as green designer solvents. We first demonstrated that ionic liquids acted as good medium for lipase-catalyzed production of polyesters. The polycondensation of diethyl adipate and 1,4-butanediol using lipase CA as catalyst efficiently proceeded in l-butyl-3-methylimidazolinium tetrafluoroborate or hexafluorophosphate under reduced pressure. The polymerization of diethyl sebacate and 1,4-butanediol in l-butyl-3-methylimidazolinium hexafluorophosphate took place even at room temperature in the presence of lipase BC. ... 

Polycondensation pol5mers, like polyesters or polyamides, are obtained by condensation reactions of monomers, which entail elimination of small molecules (e.g. water or a hydrogen halide), usually under acid/ base catalysis conditions. Polyolefins and polyacrylates are typical polyaddition products, which can be obtained by radical, ionic and transition metal catalyzed polymerization. The process usually requires an initiator (a radical precursor, a salt, electromagnetic radiation) or a catalyst (a transition metal). Cross-linked polyaddition pol5mers have been almost exclusively used so far as catalytic supports, in academic research, with few exceptions (for examples of metal catalysts on polyamides see Ref. [95-98]). 

There is a wide diversity of chemical structures of anthraquinone colorants. Many anthraquinone dyes are found in nature, perhaps the best known being alizarin, 1,2-dihydroxyanthraquinone, the principal constituent of madder (see Chapter 1). These natural anthraquinone dyes are no longer of significant commercial importance. Many of the current commercial range of synthetic anthraquinone dyes are simply substituted derivatives of the anthraquinone system. For example, a number of the most important red and blue disperse dyes for application to polyester fibres are simple non-ionic anthraquinone molecules, containing substituents such as amino, hydroxy and methoxy, and a number of sul-fonated derivatives are commonly used as acid dyes for wool. 

Lindroos, S. Kanniainen, T. Leskela, M. 1997. Growth of zinc sulfide thin films by successive ionic layer adsorption and reaction—(SILAR)—method on polyester substrates. Mater. Res. Bull. 32 1631-1636. 

Polyester polyols, 25 464 468 Polyester resin(s), 11 302 coating resins, 7 104-106 cyclopentadiene and dicyclopentadiene applications, 8 230 flammability of, 20 115-116 properties in powder coating, 7 43t standard test methods for, 20 11 It unreinforced, 10 187t weathering of, 20 116 Polyester resin-based powder coatings, organic titanium compounds in, 25 125 Polyester resin composites, 26 762-763 Polyester resin formulations ingredients of, 20 96t unsaturated, 15 511-512 Polyesters, 10 185-189, 497 12 655-656. See also Thermoplastic polyesters Unsaturated polyesters acid resistance of, 20 7-8 antioxidant applications, 3 121 aromatic ionic, 23 722 based on 1,4-cyclohexanedimethanol, 12 674-675... 

The SSP behavior of co-polyesters with rigid or voluminous comonomers, such as the flame retardant additive 9,10-dihydro[2,3-di-9-oxa-(2-hydroxyethoxy)-carbonylpropyl]-10-phosphaphenanthrene-10-oxide, or the ionic compound, sodium 5-sulfoisophthalate, is inhibited. This also occurs in the melt phase and cannot be improved by the use of catalysts [56], The results of studies examining the influence of employed catalysts with respect to stability and quality of the polymer suggest the use of antimony catalysts. The thermal or thermo-oxidative stability is, however, reduced by the interaction of the catalyst with the carboxylic groups of the polymer [57],... 

Control of fiber friction is essential to the processing of fibers, and it is sometimes desirable to modify fiber surfaces for particular end-uses. Most fiber friction modifications are accomplished by coating the fibers with lubricants or finishes. In most cases, these are temporary treatments that are removed in final processing steps before sale of the finished good. In some cases, a more permanent treatment is desired, and chemical reactions are performed to attach different species to the fiber surface, e.g. siliconized slick finishes or rubber adhesion promoters. Polyester s lack of chemical bonding sites can be modified by surface treatments that generate free radicals, such as with corrosive chemicals (e.g. acrylic acid) or by ionic bombardment with plasma treatments. The broken molecular bonds produce more polar sites, thus providing increased surface wettability and reactivity. 

Most addition polymers are formed from polymerizations exhibiting chain-growth kinetics. This includes the typical polymerizations, via free radical or some ionic mode, of the vast majority of vinyl monomers such as vinyl chloride, ethylene, styrene, propylene, methyl methacrylate, and vinyl acetate. By comparison, most condensation polymers are formed from systems exhibiting stepwise kinetics. Industrially this includes the formation of polyesters and polyamides (nylons). Thus, there exists a large overlap between the terms stepwise kinetics and condensation polymers, and chainwise kinetics and addition (or vinyl) polymers. A comparison of the two types of systems is given in Table 4.1. 

A change of architecture is another route that enables diversification of the properties of aliphatic polyesters. This review will focus on star-shaped, graft, macrocyclic, and crosslinked aliphatic polyesters. It must be noted that the ROP of lactones has been combined with several other polymerization mechanisms such as ROP of other heterocyclic monomers, ionic polymerization, ROMP, and radical polymerization. Nevertheless, this review will not cover these examples and will focus on polymers exclusively made up of poly(lactone)s. 

A cumulative success of artificial ion-channel functions by simple molecules may disclose a wide gate for the design of ion channels and possible applications to ionics devices. Incorporation of these channels into bilayer lipid membrane systems may trigger the developments towards ionics devices. The conventional BLM system, however, is not very stable, one major drawback for the practical applications, and some stabilization methods, such as impregnating the material in micro-porous polycarbonate or polyester filters, are required. On the other hand,... 

Lipase-catalyzed transesterification to prepare polyesters (replacing the traditional chemical polymerization at >200 °C) has received considerable attention in recent years. CaLB was found to mediate polyester synthesis in the ionic liquids [BMIm][BF4], [BMIm][PF6], and [BMIm][ Tf2N] at 60°C [110, 111, 112], but the molecular weight of the product was rather low compared with that in a solventless system [113], perhaps owing to the high viscosity of ionic liquid media. 

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