Polyurethane Glycol extender

The most important chain extenders are ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, cyclohexanedimethanol, and hyroquinone dihy-droxyethyl ether. Recently, 1,3-propanediol (57) and 1,2,4-butanetriol (58) have become available as new polyurethane raw materials. Since ethylene glycol-extended polyurethanes are prone to thermal degradation, ethylene glycol is only used as a RIM extender in thermoset polyurethanes. 

Tartaric acid-glycerol polyesters were reported in 1847 by Berzelius [13] and those of ethylene glycol and succinic acid were reported by Lorenzo in 1863 [14]. Carothers and Van Natta [15] extended much of the earlier work and helped clarify the understanding of the polyesterification reaction in light of the knowledge of polymer chemistry at their time. Polyethylene terephthalate [16, 17] and the polyadipates [18] (for polyurethane resins) were the first major commercial application of polyesters. 

Polyurethanes (PU s). SL and 4,4 -diphenylmethane diisocyanate (MDI) were dissolved in tetrahydrofuran (THF), and the solution was stirred for 1 hr at 60°C. A THF solution of polyethylene glycol (PEG 400) and diethyl bis(2-hydroxyethyl)aminomethylphosphonate (polyol containing phosphorous) was added to the reaction mixture, and the reaction time was extended for 1 hr. In all reactions, the molar ratio of the total amount of isocyanate groups to the total amount of hydroxyl groups (NCO/OH) was maintained at 1.2. The lignin content in PU was 20 wt%. Each solution was drawn on a glass plate, and allowed to dry for 48 hr. The residual solvent in a sample was removed under vacuum and curing of each PU film was carried out at 120°C for 3 hr under a pressure of 50 kg/cm2. 

A recent example of XPS analysis of polyurethane surfaces has been provided by Yoon et al. [30]. In these studies polyurethanes were prepared with 4.4 -methylenebisfphenyl isocyanate) (MDI)and hexafluoro- l.5-pentancdiol (FP) extenders as the hard segment, and poly(tetramethylene glycol) (PTMO) as the soft segment. The authors introduced hydrophobic soft segments, either poly-(dimethylsiloxan) (PDMS) or polyisobutylene (PIB) into this polyurethane structure. The concept underlying this polymer design was the desire to modify sur-... 

Synthesis and Modification. A series of polyurethanes and polyurethane-ureas of varying degress of hydrophilicity and hydrophobicity and mechanical property were synthesized. The polymers were prepared by a solution polymerization method and consisted of three components a polyether, a diisocyanate, and a chain extender. In our studies, polyurethanes (Table I) were based on a carbowax (polyoxyethylene glycol), MDI (methylene bis-4-phenyl isocyanate) and 1,5-pentanediol. Polyurethane-ureas (Table II) were obtained by substituting the chain extender from a diol to a diamine. The polyurethane-ureas (Table II) were obtained by changing the chain extender from a diol to a more reactive diamine. The polyurea-urethanes (Table III) were obtained by using a diamine terminated polyether instead of the carbowax. 

In most of our studies, modification of the synthetic route was limited to only one variable, the chain length of the polyether component. The same molar ratio of polyether/chain extender disocyanate (MDI) and chain extender (diethlene glycol) were used. The molecular weight of the polyether component of J-20, J-9 and J-6 was 2,000, 1,000 and 600 respectively. A wide range of properties was obtained from this series of polyurethanes. Properties intermediate between J-20 and J-9 were also obtained by... 

By the reaction of a prepolymer with a chain extender such as ethylene glycol, diethylene glycol, 1,4 butane diol or a diamine, the high molecular weight polyurethanes are formed (see Equation 2.5). 

NSC 406696 Suool B Tetramethylene 1,4-diol Tetramethylene glycol 1,4-Tetramethylene glycol. Curative, chain extender provides reactive H-source in prepolymer production used to provide hard segments in PU. Used as an intermediate and in polyurethane formulation in the hard segment as a curative. Crystals mp = 20.1° bp = 235° = 1.0171 Xm = 291 nm (e = 200, H2SO4) freely... 

Polyurethane. [This polymer was supplied by R. A. Auerbach, Lord Corporation.] The polyurethane was composed of a soft segment of poly(tetramethylene glycol) with a molecular weight of 1000 and a hard segment of p-diphenylmethane 4,4 -diisocyanate (MDI), and was chain extended with ethylenediamine (7). A solution of 7 wt % polyurethane in N,N-dimethylacetamide was used to cast the films. The phase-separated samples (ANN) were prepared by annealing the film at 135°C for 90 min in a helium atmosphere, and the mixed, nonphase-separated samples (NEQ)... 

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