Acidity polytetrahydrofuran

Both polyethers and polyesters may be used as polyols. For example, Du Pont use polytetrahydrofuran for Lycra whilst US Rubber originally used a polyester of molecular mass of about 2000 obtained by condensing adipic acid with a mixture of ethylene and propylene glycols. A polyether-based mixture was used for Vyrene 2 introduced in 1967. All the polyols have terminal hydroxyl groups. 

A third example combines cationic ROP and ATRP for the synthesis of (polytetrahydrofurane)(poly-l,3-dioxepane)(PS) miktoarm stars (Scheme 99). The initiating sites for the above polymerization were created step-by-step from amino-succinic acid (Scheme 99). 

To the first category belong the homo- and copolymerization of macromonomers. For this purpose, macromolecules with only one polymerizable end group are needed. Such macromonomers are made, for example, by anionic polymerization where the reactive chain end is modified with a reactive vinyl monomer. Also methacrylic acid esters of long-chain aliphatic alcohols or monofunctional polyethylene oxides or polytetrahydrofurane belong to the class of macromonomers. 

Polymers with composition [NP(02Ci2Hg)] .x(0C4H8) have been formed in the reaction of (NPCl2) with 2,2 -diphenol in thf. Polytetrahydrofurane (OC4Hg) arises from acid-catalyzed ring opening polymerization of thf. ... 

Renewable materials can be used in the preparation of polyurethanes. Glycosides of polytetrahydrofuran have been used with diisocyanates.164 Castor oil (which contains about 2.7 OH per molecule) has also been used.165 Polyols derived from epoxidized soybean oil have been used to make polyurethanes.166 Lactic acid oligomers can be used.167 Wheat Board is made from wheat straw and isocyanates.168 It is said to be lighter and as strong as and more resistant to moisture than conventional particle board. No formaldehyde is needed for this building material. 

Unfortunately, DMC catalysts are not efficient for EO polymerisation, and it is practically impossible to obtain PO-EO block copolymers with this catalyst. Acidic catalysts are not used on an industrial scale for alkylene oxide polymerisation due to the formation of substantial amounts of cyclic ethers as side products. Acidic catalysts are used industrially only for the synthesis of polytetrahydrofuran polyols or, to a lesser extent, for tetrahydrofuran - alkylene oxide copolyether polyol fabrication (see Sections 7.1, 7.2 and 7.3) Other catalysts have a minor importance for large scale polyether polyol production. 

Synonyms Poly (polytetrahydrofuran carbonate) diol Tetrahydrofuran, compd. with carbonic acid Classification Polymer... 

Poly (1,4-phenylene sulfide) resin. See Polyphenylene sulFrde resin Poly [(phenyl glycidyl ether)-co-farmaldeh e. See Epoxy-novolac Polyphenylmethyl siloxane. See Phenyl methicone Phenyl trimethicone Polyphosphoric acid, ammonium salt. SeeAmmonium polyphosphate Poly (polytetrahydrofuran carbonate) diol. See Polyether-polycarbonate diol... 

Hydrogen tetrafluoroborate. See Fluoboric acid Hydroguard 1-15. See Isopropylhydroxylamine a-Hydro-uj-hydroxypoly (oxy-1,4-butanediyl) linear chain polymer. See Polytetrahydrofuran a-Hydro-u-hydroxypoly [oxy (methyl-1,2-ethanediyl)] a-Hydro-w-hydroxypoly (oxypropylene). See Polypropylene glycol Hydroiodic acid. See Hydriodic acid Hydroiodide-enterol. See lodochlorohydroxyquinoline Hydrokeratin 100M Hydrokeratin AL-30 Hydrokeratin AL-SD. See Hydrolyzed keratin Hydrokeratin HH-20SF. See Hair keratin amino acids... 

Details of the manufacture of polytetrahydrofuran have not been disclosed. Because of the stability of the 5-membered ring in tetrahydrofuran, combinations of Lewis acids with water are not very effective initiators. More active cationic initiators are preformed carbonium salts (e.g., (C6Hs)3C SbCl6") and oxonium salts (e.g., (C2H5 )30 BF4"). The mechanism of reaction is thought to be fundamentally similar to that given above (Section 8.4.5) for the polymerization... 

The promise of large-scale low-cost fermentations from renewable resources, especially corn, has spurred interest in the United States to develop chemical production for large-volume chemicals using bio-based processes. Succinic acid can be converted by hydrogenation to 1,4-butanediol, which has a world market in excess of 500,000 metric tons. Butanediol is used to produce polybutylene terephthalate (PBT) resins that have desirable mechanical and thermal properties and are a high-performance version of polyethylene terephthalate resins (PET). Also, 1,4-butanediol is a precursor of tetrahydrofuran, which can be polymerized to polytetrahydrofuran (PTHF). Gamma butyrolactone (GBL) can also be derived from 1,4-butanediol, and much of GBL is used to manufacture the solvent N-methyl-2-pyrrolidone (Szmant 1989). 

Other polymers whose structure has been examined by SEC-MS include poly-3-hexylthiophene [34], styrene oligomers [35], PS [5, 36-38], e-caprolactone [39, 40], polytetrahydrofuran [41] macrocyclic vinyl polymers [42], bis (metholol propionic acid) dendrimers [43], poly-isocyanates [44], isosorbide diols [45], 3,5-diacetoxybenzoic acid polyesters [46], polyethylene and polypropylene oxide condensates and PEG containing a 1,3 disubstituted phenolic group [37]. 

Mumcu S, Burzin K, Feldmann R and Feinauer R (1978) Copolyetheramides from laurolactam, decane-1,10-dicarboxylic acid and a,w-dihydroxy(polytetrahydrofuran), Angew Makromol Chem 74 49-60. 

The FTIR has been extensively used in studying the compositions of polysiloxanes as well as for monitoring the reaction process as a function of time. Tejedor et al. [3] studied the hydrolysis and condensation of alkoxysilanes with FTIR in acidic medium. The authors conducted the in-situ ATR-FTIR analysis on acidified solution of tetraethylorthosilicate (TEOS) and noticed that the rate of hydrolysis increased with the decrease in pH of the acidic medium. Similarly, the deconvolution of skeletal (SiOSi) FTIR bands in a film produced by reacting TEOS and polytetrahydrofuran suggested the formation of porous network that retains significant proportion of four-fold siloxane ring structures [4]. 

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