Polyether/polyesters

Propylene oxide (qv) uses include manufacture of polyurethanes, unsaturated polyester, propylene glycols (qv) and polyethers, and propan o1 amines (see Alkanolamnes Glycols Polyethers Polyesters, unsaturated Urethane polyt rs). 

In addition, polyester polyols are made by the reaction of caprolactone with diols. Poly(caprolactone diols) are used in the manufacture of thermoplastic polyurethane elastomers with improved hydrolytic stabiHty (22). The hydrolytic stabiHty of the poly(caprolactone diol)-derived TPUs is comparable to TPUs based on the more expensive long-chain diol adipates (23). Polyether/polyester polyol hybrids are synthesized from low molecular weight polyester diols, which are extended with propylene oxide. 

YBPO thermoplastic block polyether-polyester rubbers... 

The polyols used are of three types polyether, polyester, and polybutadiene. The polyether diols range from 400 to about 10,000 g/mol. The most common polyethers are based on ethylene oxide, propylene oxide, and tetrahydrofuran or their copolymers. The ether link provides low temperature flexibility and low viscosity. Ethylene oxide is the most hydrophilic and thus can increase the rate of ingress of water and consequently the cure rate. However, it will crystallize slowly above about 600 g/mol. Propylene oxide is hydrophobic due to hindered access to the ether link, but still provides high permeability to small molecules like water. Tetrahydrofuran is between these two in hydrophobicity, but somewhat more expensive. Propylene oxide based diols are the most common. 

R" can represent a wide variety of backbones, such as polyethers, polyesters, etc. These backbones will be discussed shortly. In actual practice, most prepolymers are made with NCO/OH ratios as low as 1.4, but the ratios can be as high as 3.0 or greater. 

In light of the considerable recent Interest in the macrocyclic polyether-polyester antibiotics, Samat and coworkers have prepared a large-ring macrocycle as a model for the... 

Weathering Many plastics has short lives when exposed to outdoor conditions. The better materials include acrylic, chlorotri-fluorethylene, vinylidene fluoride, chlorinated polyether, polyester, alkyd, and black linear poly-ethylene. Black materials are best for outdoor service. Some of the styrene copolymers are suitable for certain outdoor uses (Chapter 2, WEATHERING/ ENVIRONMENT). 

Poly(ether ester) (PEE) copolymers were consisted of soft segments of polyethers and hard crystalline segments of polyesters. Depending on the polyether/polyester ratio, PEE copolymers exhibit a wide range of mechanical behavior combined with solvent resistance, thermal stability, and ease of melt process ability. 

Multiblock copolymers are synthesized by step polymerization using prepolymers containing specific end-groups (Eq. 14). Polyester- and polyether-polyurethanes and polyether-polyesters are multiblock copolymers of commercial interest. Step polymerizations has advantages over living polymerization. There is a... 

Thermoplastic elastomeric behavior requires that the block copolymer develop a microheterogeneous two-phase network morphology. Theory predicts that microphase separation will occur at shorter block lengths as the polarity difference between the A and B blocks increases. This prediction is borne out as the block lengths required for the polyether-polyurethane, polyester-polyurethane, and polyether-polyester multiblock copolymers to exhibit thermoplastic elastomeric behavior are considerably shorter than for the styrene-diene-styrene triblock copolymers. 

The nature of the hard domains differs for the various block copolymers. The amorphous polystyrene blocks in the ABA block copolymers are hard because the glass transition temperature (100°C) is considerably above ambient temperature, i.e., the polystyrene blocks are in the glassy state. However, there is some controversy about the nature of the hard domains in the various multiblock copolymers. The polyurethane blocks in the polyester-polyurethane and polyether-polyurethane copolymers have a glass transition temperature above ambient temperature but also derive their hard behavior from hydrogen-bonding and low levels of crystallinity. The aromatic polyester (usually terephthalate) blocks in the polyether-polyester multiblock copolymer appear to derive their hardness entirely from crystallinity. 

Polyether-polyester polyol hybrids, 25 472 Polyetherimide-polysiloxane block copolymers, 24 698, 704, 708... 

Telechelic polymers rank among the oldest designed precursors. The position of reactive groups at the ends of a sequence of repeating units makes it possible to incorporate various chemical structures into the network (polyether, polyester, polyamide, aliphatic, cycloaliphatic or aromatic hydrocarbon, etc.). The cross-linking density can be controlled by the length of precursor chain and functionality of the crosslinker, by molar ratio of functional groups, or by addition of a monofunctional component. Formation of elastically inactive loops is usually weak. Typical polyurethane systems composed of a macromolecular triol and a diisocyanate are statistically simple and when different theories listed above are... 

Jin, L. and Nava, H., High performance polyether-polyester containing laminating resin composition, World Patent Wo 0 116 207, 2001. 

Compared to polyethers, polyester foams generally present ... 

Elastollan Polyurethane block copolymer with polyether/polyester BASF... 

Grilamid Polyamide copolymer with polyether/polyester nylon-12 EMS America Grilon... 

EMA copolymer Acrylic Polyester fiber Polyamide copolymer with polyether/polyester Epoxy and PVC powders Nylon-6 Acrylic fibers Poromeric film Vinyl Vinyl PVC... 

With very short "blocks", snch as in the random-copolymer SBR, there is only a very small difference in entropy between the segregated and the homogeneous condition no or hardly any change of entropy npon segregation. As the block length increases, this difference, however, increases, so that (G decreases (see MT 9.1.4). Segregation is, therefore, less complete in mnlti-block copolymers (such as polyethers- polyesters). 

In this chapter, polymerization of epoxides and co-polymerization of epoxides with GO or GO2, which give polyethers, polyesters, and polycarbonates, respectively, are reviewed. During the last decade, significant advances... 

Fig. 10. Internal energy changes as a function of deformation for oriented LDPE (I) and stress softened thermo-elastoplastic polyurethanes with 50% (2) and 42 % (3) hard phase content and polyether-polyester block copolymer with 48% hard phase content (4). The dotted curves 1 and 2 represent intramolecular energy changes for the corresponding polymers119 ...

Much attention has been paid to the synthesis of fluorine-containing condensation polymers because of their unique properties (43) and different classes of polymers including polyethers, polyesters, polycarbonates, polyamides, polyurethanes, polyimides, polybenzimidazoles, and epoxy prepolymers containing pendent or backbone-incorporated bis-trifluoromethyl groups have been developed. These polymers exhibit promise as film formers, gas separation membranes, seals, soluble polymers, coatings, adhesives, and in other high temperature applications (103,104). Such polymers show increased solubility, glass-transition temperature, flame resistance, thermal stability, oxidation and environmental stability, decreased color, crystallinity, dielectric constant, and water absorption. 

The synthesis of PU can be carried out by the reaction described in Eq. (2.24). If the functionality of the hydroxy-containing compounds or the isocyanate is increased beyond 2, branched and possibly crosslinked polymers are produced. Because the nature of the polyol (polyether, polyester, polybutadiene, etc.) and isocyanate components can vary widely, PU are among the most versatile polymers, producing a wide variety of materials such as elastomers, foams, coatings, adhesives, or fibers. 

Instead of a, co-dihydroxylated polysiloxanes, other a, co-dihydroxy-lated organic polymers such as polyether, polyester, or polybutadiene can be used to prepare hybrid organic-inorganic networks. 

Block copolymers characterised by different backbone structures of well-defined block lengths have been obtained from oxiranes and other heterocyclic monomers in the presence of catalysts that are effective at bringing about living polymerisations. Aida et al. [127,188,189,195,196] applied aluminium porphyrins and Teyssie et al. [125,197,198] applied bimetallic /i-oxoalkoxidcs for block copolymerisations in systems involving oxirane lactone, oxirane oxirane/cyclic acid anhydride, and oxirane/cyclic acid anhydride lactone as block forming units and obtained respective polyether polyester and polyester polyester block copolymers. Such copolymers seem to be of exceptionally wide potential utility [53]. 

K, is nearly 100 for EDA and DETA since there is no restraint in the molecules of the curing agents q(E ) is higher and Tg is slightly elevated in Im and Sue A since the restraint is high. This is due to increasing flexibility of the main chain in the series hydrocarbon < polyether < polyester. For DGEBA resins, Tg increases in the series amine- > catalyst- > acid anhydride, for the same valne of q(E.,. 

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