Urethane-based polymers

Another family of polyols is the filled polyols.llb There are several types, but die polymer polyols are die most common. These are standard polyether polyols in which have been polymerized styrene, acrylonitrile, or a copolymer thereof. The resultant colloidal dispersions of micrometer-size particles are phase stable and usually contain 20-50% solids by weight. The primary application for these polyols is in dexible foams where the polymer filler serves to increase foam hardness and load-bearing capacity. Other filled polyol types diat have been developed and used commercially (mainly to compete with die preeminent polymer polyols) include the polyurea-based PEID (polyhamstoff dispersion) polyols and the urethane-based PIPA (poly isocyanate polyaddition) polyols. 

The miscibility between poly (vinyl chloride) and poly-urethanes based on poly (oxytetramethylene) glycol can be improved by introducing opposite charge groups to form ionic bonds. The improvement in miscibility from ionic bonds between the two polymer systems provided the best chance for interpene-tration between the linear chains of VMCC and the PU networks in order to obtain good physical properties of the ionomer pseudo-IPN coatings from PU and VMCC. 

In addition to its use in PTT, 1,3-propanediol can replace traditional glycols in urethane-based polymer systems, improving thermal and hydrolytic stability. As a partial substitute for traditional glycols in polyester systems, 1,3-propanediol can improve coating flexibility without affecting other key properties. Other applications include engine coolants and water-based inks (33). 

Knaub P, Camberlin Y (1988) Gerard JF, New reactive polymer blends based on poly(urethane ureas) (PUR) and polydisperse poly(dimethylsiloxane) (PDMS) control of morphology using a PUR-b-PDMS block copolymer. Polymer 29(8) 1365-1377... 

An urethane-based pressure-sensitive adhesive composed of a liquid hydroxytelechelic polybutadiene and a polyisocyanate does not require a solvent in coatings onto label sheets. This polymer together with the (polystyrene-co-butadiene) copolymer and a polyisocyanate was applied in steel coatings 239 240>. 

The very slow rate of reaction between an orfho-substituted isocyanate and an ortho-substituted amine in the cure of polyurea-urethanes based on tolylene diisocyanate has been considered to be of significant importance in the final cure of such polymers [180]. 

Urethane-Based IPN Foams. Interpenetrating polymer networks (IPNs) are types of polymer alloys composed of the entanglement of at least two cross-linked components (112). An ideal IPN has essentially no covalent bonds between the polymers. The resulting morphology shows... 

Urethane-Based Hybrid Foams. Hydroxyl-terminated ester oligomers or vinyl esters which have terminal vinyl groups and pendant hydroxyl groups can react simultaneously with isocyanate groups and vinyl monomers in the presence of catalysts to obtain crosslinked hybrid polymers. 

Table II lists the thermal transitions by DSC and IMA of four different urethane polymer systems based on thepreceding hard and soft segment combinations. While PPG-2025rnr was used in place of Poly G-53-56, it should behave the same since it has no ccmpatibilizing EO. Figures 2 and 4 exhibit the respective DSC and IMA curves of these polymers ...

U35. [BFGoodrich/Spec. Polymers] Polyester-based aq. aliphatic urethane db-persion skincoat for transfer coating applies. 

In this section, the future developments will be discussed that might be expected in commercial polymer blends comprising at least one of the constituents from the class of commodity polymers. Generally, the commodity polymers considered include polyethylene (and variants LDPE, HOPE, LLDPE, VLDPE and ethylene copolymers), polypropylene (PP), ethylene-propylene rubber (EPR and EPDM), polyvinylchloride (PVC), polystyrene (PS), ABS, and poly(methyl methacrylate) (PMMA). Elastomeric polymers commonly used in tire and associated applications are important in polymer blends as many tire component constructions employ polymer blends to maximize performance. However, these will not be considered here. Thermosetting polymers which could be classified as commodity polymers (urethane, phenolics, epoxies) will also not be covered, but will be mentioned in a later section discussing new polymer blends designed for specific applications (e.g., water based coatings). 

Kosyanchuk, L. E, Babkina, N. V., Yarovaya, N. V, Kozak, N. V, and Lipatov, Y. S., 2008. Phase separation in semi-interpenetrating polymer networks based on crosslinked poly(urethane) and linear p>oly(methyl methacrylate) containing iron, copper, and chromium chelates. Polymer Science Series A 50(4) 434-433. 

Saad, G.R., Lee, Y.J. and SeUger, H. (2001) Synthesis and characterization of biodegradable poly (ester-urethanes) based on bacterial poly (R-3-hydroxybutyrate). Journal of Applied Polymer Science, 83(4), 703-718. 

Other tertiary recycling processes that have been developed include a Freeman Chemical Corp. process to convert PET bottles and film to aromatic polyols used for manufacture of urethane and isocyanurates. Glycolized PET, preferably from film, since it is often lower in cost than bottles, can be reacted with unsaturated dibasic acids or anhydrides to form unsaturated polyesters. These can then be used in applications such as glass-fiber-reinforced bath tubs, shower stalls, and boat huUs. United States companies that have been involved include Ashland Chemical, Alpha Corp., Ruco Polymer Corp., and Plexmar. Unsaturated polyesters have also been used in polymer concrete, where the very fast cure times facilitate repair of concrete structures. Basing polymer concrete materials, for repair or precast applications, on recycled PET reportedly leads to 5 to 10 percent cost savings and comparable properties to polymer concrete based on virgin materials. However, they are still approximately 10 times the cost of portland cement concrete. There appears to be little commercial application of these processes at present. 

Increase in crosslink density, type of crosslinking and introduction of isocyanurate ring structures in the polymer-chain backbone has a strong beneficial effect on the thermal stability of polyurethanes and is discussed later in this chapter. It is known that thermal stability increases with increasing isocyanate content of urethane elastomers, and in addition to the formation of the thermally stable isocyanurate rings, stability is influenced by the different types of urethane-based groups formed, as shown in Table 3.9a. 

G. C. Meyer and P. Y. Mehrenberger, Polyester-Polyurethane Interpenetrating Networks, Eur. Polym. J. 13(5), 383 (1977). Urethane-based SINs. 

Ferreira et al. [75] synthesized a HMA for medical use. Urethanes based on polycaprolactone diol (PCL) were synthesized by reaction of the molecule either with isophorone diisocyanate (IPD-isocyanate) or hexamethylene diisocyanate (HDI-isocyanate). Nies Berthold et al. [76] tried out an adhesive composition based on polymers or polymer blends consisting of caprolactone copolymers or caprolactone copolymers and polycaprolactone. The adhesive can be utilized as HMA for temporarily gluing together biological tissue and other materials in medicine. 

The spin traps technique was applied to the study of photoinitiation of polymer (coatings based on polyester-urethanes) degradation [730,731, 733, 734]. There is excellent qualitative correlation between the rate of... 

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