Polyethers polytetrahydrofuran

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). 

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. 

High-Impact Resins from Polytetrahydrofuran. The only polyether successfully used alone to produce high-impact resins was PTHF. (Brittle resins were obtained from all the other polyethers tried.) Both PVC (Figure 1) and CPVC (Figure 2) could be improved in Izod impact strength by addition of PTHF. As usual, high impact strength did... 

The results for a Py-GC/MS analysis of a polyether-urethane are shown In Figure 14.1.1. The compound Is poly[4,4 -melhylenebls(phenyl isocyanate)-a/f-butandiol/polytetrahydrofuran], CAS 9018-04-6. The pyrolysis was done at 600° C in He in conditions similar for other examples previously discussed (see Table 4,2,2). 

Increasing hydrophilicity by selecting polyethers longer carbon chain polyoxyethylene (2 C) < polyoxypropylene (3 C) < polytetrahydrofurane (4 C). 

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. 

Polytetrahydrofuran (PTHF) is a polyether obtained by cationic ring opening polymerisation of tetrahydrofuran (THF), a five membered cyclic ether ... 

The superior characteristics of polyester polyol based polyurethanes are explained by a better crystalline structure [1, 7] in the urethane segment, compared to the majority of poly ether polyols which are amorphous [except polytetrahydrofuran (PTHF)], due to the superior secondary forces between the polyester chains [8] and also due to a superior thermal and fire resistance, compared to polyether polyol based polyurethanes. Polyester-based polyurethanes (flexible foams, coatings), have a superior solvent resistance compared to the polyether-based polyurethanes [8]. 

Thus, from high MW diols (MW = 1000-4000 daltons) polyethers (polyalkyleneoxides, polytetrahydrofuran (PTHF)), polyesters, polycarbonates (PC), polybutadienes, etc., by the reaction with diisocyanates [toluene diisocyanate (TDI), or pure diphenyl methane diisocyanate (MDI)], high MW linear polyurethanes are obtained (no crosslinking), with high elasticity (polyurethane elastomers, spandex fibres, some adhesives and sealants, etc). 

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... 

Poiypiasdone iNF-10, Poiypiasdone XL, Poiypiasdone XL-10. See Crospovidone Poiypiastoi 10. See Pentaerythrityl stearate Poiypiastoi 23. See Zinc 2-ethylhexanoate Poiypiate 90, Poiypiate 852, Poiypiate P, Poiypiate P01. See Kao I i n PoiypoilQ. See Polypropylene Poly (polytetrahydrofuran carbonate) diol. See Polyether-polycarbonate diol Polypropene. See Polypropylene Polypropylene CAS 9003-07-0... 

Common SS include polyethers, polyesters and polyalkyl glycols with glass transition temperatures in the range of -70°to -30°C. Commonly used macrodiols in the PUs synthesis are polyalkyl-diols, such as polyisobutylene diol [70], polybutadiene (PBU) [20, 71], or oligo-butadiene diols [72] as well as hydrogenated polybutadiene diol [20] polyether diols polytetrahydrofuran (PTHF or PTMO) [50-52], polyethylene glycol (PEG) or (PEO) [73], polypropyleneoxide (PPO) [73] or mixed blocks of them PEO-PPO-PEO [74] and PPO-THF [54] polyester diols poly(ethylene adipate) (PEA) [4,20], poly(butylene adipate) (PBA) [20, 73], and latterly polycaprolactone diol (PCL or PCD) [75], polyalkylcarbonate polyol [20] or mixed blocks of them, for example poly(carbonate-co-ester)diol [76], poly(hexamethylene-carbonate)diol [77], as well as poly(hexamethylene-carbonate-co-caprolactone)diol [78] and a mixed block copolymer of polyether and polyester blocks PCL-b-PTHF-b-PCL [79]. Examples schemes of macrodiols are shown in Eig. 1.9. 

In the PU synthesis we started from one mole of hydroxy-terminated macro-diol which was either a polyester type—polyethylene adipate (PEA) or a polyether type—polytetrahydrofuran (PTHF). 

Polyethylene adipate (MW 2000) (polyester) Polytetrahydrofuran (range of MWs) (polyether)... 

Polyether polyols based on polytetramethylene oxide (PTMO), sometimes called polytetrahydrofurane (PTHF), have better strengths than PPG polyols, mainly due... 

The addition of antihydrolysis agents is required in many engineering applications. Particularly useful are diarylcarbodiimides with alkyl substituents in an ortho-position to the -N=C=N group. Although polyethers, such as polytetrahydrofuran, are not hydrolytically degraded because of their chemical structure, in Europe considerably more polyester is used than polyether. This can be explained by the positive effect of carbodiimides as hydrolysis stabilizers that are tailored to specific applications. The additive load ranges from 0.5 to 2%. Its protective effect is not influenced by whether carbodiimide is added directly to the polyester or to the prepolymers. In... 

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