Polyurethanes groups

Technical Data Sheet PU15", ICI Polyurethanes Group, ICI Europa, Belgium. 

Solderable wires are used in telecommunications and the construction of analytical instruments, but they are becoming more and more common in small motors and dry-type transformers. The special characteristic of solderable wire enamels is the direct soldering. When the enameled wire is dipped in a solder bath at temperatures above 350 °C the coating melts and leaves the bare copper wire, avoiding the need for elaborate mechanical or chemical removal of the enamel. This characteristic achieved in solderable poly(ester-imide) by a special polymer composition and in polyurethane based wire enamels is due to the thermally reversible splitting of the polyurethane group. Nevertheless, good thermal stability is necessary and product temperature indexes >155 are required. For temperature indexes of 130, simply polyurethane wire enamels were used. 

Methods to dissolve the polymer binders used to hold energetic materials also are being developed. Polyurethane-based polymers are commonly used as binders for propellants and explosives. By undergoing hydrolysis at 230°C (445°F), the polyurethane groups in the binder split. The mixture is then treated by solvent extraction to recover both polyols and energetic materials from the binder. 

IQ Polyurethanes Group/Foonnlated Products Div., 6555 Fifteen Mile Rd, Sterling Heights, MI 48077 (Tel. 313-826-7660 800-553-8624)... 

ICI Polyurethanes Group/West Deftford Div., Mantua Grove Rd., West Deptftnd, NJ 08066 (TeL 609-423-8300 800-257-5547)... 

Acoustiflex, Polyurethane flexible foam systems, ICI Polyurethanes Group... 

Rnbillex, Polyurethane flex foam systems, ICl Polyurethanes Group... 

It should be mentioned that the Contributors, the Editor, as well as the Publisher are well aware that, strictly speaking, the title Condensation Thermoplastic Elastomers is chemically not sufficiently correct for the covered classes of polymers. Nevertheless, it was preferred, e.g., to the chemically correct title Thermoplastic Elastomers by Poly condensation and Polyaddition , at least for the following reasons (i) the polyurethane group behaves chemically much more as a typical polyester or polyamide group, rather than as a polyolefin, (ii) similarly to other cases e.g., the synthesis of nylon 6) regardless of the chemical route of the synthesis, via polymerization or via polycondensation, the final polymer is distinguished by a chemical structure typical of polycondensates, and (iii) the selected title sounds more comprehensive and more attractive. 

The hydroxyl groups can be esterified normally the interesting diacrylate monomer (80) and the biologicaky active haloacetates (81) have been prepared in this manner. Reactions with dibasic acids have given polymers capable of being cross-linked (82) or suitable for use as soft segments in polyurethanes (83). Polycarbamic esters are obtained by treatment with a diisocyanate (84) or via the bischloroformate (85). 

Polyurethanes. About 3% of the U.S. polyurethanes market in 1988 was derived from the condensation product of polyisocyanates with low molecular weight polyadipates having hydroxyl end groups (195). In 1986 this amounted to 29,000 t, or 4% of total adipic acid consumption. The percentage was similar in Western Europe. About 90% of these adipic acid containing polyurethanes are used in flexible or semirigid foams and elastomers, with the remainder used in adhesives, coatings, and spandex fibers. 

Diester/Ether Diol of Tetrabromophthalic Anhydride. This material [77098-07-8] is prepared from TBPA in a two-step reaction. First TBPA reacts with diethylene glycol to produce an acid ester. The acid ester and propylene oxide then react to give a diester. The final product, a triol having two primary and one secondary hydroxyl group, is used exclusively as a flame retardant for rigid polyurethane foam (53,54). 

Eyrol 51 is a water-soluble Hquid containing about 21% phosphoms. It is made by a multistep process from dimethyl methylphosphonate, phosphoms pentoxide, and ethylene oxide. The end groups are principally primary hydroxyl and the compound can thus be incorporated chemically into aminoplasts, phenoHc resins, and polyurethanes. Eyrol 51, or 58 if diluted with a small amount of isopropanol, is used along with amino resins to produce a flame-retardant resin finish on paper used for automotive air filters, or for backcoating of upholstery fabric to pass the British or California flammabiHty standards. 

Synthesis and Properties. Several polymers containing HFIP-O groups have been investigated, the most common beeing epoxies and polyurethanes. The development of fluorinated epoxy resins and the basic understanding of their chemistry has been reviewed (127). 

Isocyanates can be characterized using a strong absorption at 2300 — 2200 cm in the ir spectmm. The position of the absorbance is influenced by conjugation and neighboring polar groups. This method has been successfully used in both kinetic and post-mortem characterizations of many polyurethane polymers. 

Propylene oxide and other epoxides undergo homopolymerization to form polyethers. In industry the polymerization is started with multihinctional compounds to give a polyether stmcture having hydroxyl end groups. The hydroxyl end groups are utilized in a polyurethane forming reaction. This article is mainly concerned with propylene oxide (PO) and its various homopolymers that are used in the urethane industry. 

The polymerization of tetrahydrofuran was first studied ia the late 1930s (3,4). In 1960, this work was summarized (4), and the Hterature on tetrahydrofuran polymers and polymerization has been growing ever siace. Polytetrahydrofuran with hydroxy end groups has become a large-scale commercial product, used mainly as the flexible polyether segment ia elastomeric polyurethanes and polyesters. It is commercially available under the trade names Terathane (Du Pont), Polymeg (QO Chemicals), and PolyTHF (BASF). Comprehensive review articles and monographs have been pubUshed (2,5-8). 

Reaction with Phosgene. This reaction of amino acid esters is used for preparing the corresponding isocyanates, especially lysine diisocyanate [4460-02-0] (LDI). LDI is a valuable nonyellowing isocyanate with a functional side group for incorporation in polyurethanes. 

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