Propylene oxide block

PEMA PEO PIEO POX) P(b-EO b-POX) PIER HBA) polylethyl methacrylate) polylethylene oxide) polylethylene oxide-co-propylene oxide) polylblock-ethylene oxide-co-block-propylene oxide) poly(ethyleneterephthalate-co-p-hydroxibenzoic acid)... 

Block propylene oxide. Several broad subfamilies of these surfactants were originally developed by Wyandotte Corp, later proliferated by BASE and are today produced through a process where PPG of varying molecular weight (MW) is used as the substrate for ethoxylation, or where PEG or alkyl PEG ethers of varying MW are block propoxylated. Concerns in the European Union (EU) over the anaerobic biodegradability of the block PO/EO surfactants will affect their ongoing breadth of use in consumer applications. 

Pa.sch, H., C. Brinkmann, H. Much, U. Just, Chromatographic investigations of macromolecules in the critical range of LC two-dimensional separations of poly(ethylene oxide-block-propylene oxide), 7. Chromatogr., 1992,623, 315-322. 

Fig. 6. Snapshot from a dynamic density functional simulation of the self-organisation of the block copolymer PL64 (containing 30 propylene oxide rmd 26 ethylene oxide units (EO)i3(PO)3o(EO)i3) in 70% aqueous solution. The simulation was carried out during 6250 time steps on a 64 x 64 x 64 grid (courtesy of B.A.C. van Vlimmeren and J.G.E.M. Praaije, Groningen).

Urethane Polymers. An important use for glycerol is as the fundamental building block ia polyethers for urethane polymers (qv). In this use it is the initiator to which propylene oxide, alone or with ethylene oxide, is added to produce ttifunctional polymers which, on reaction with diisocyanates, produce flexible urethane foams. Glycerol-based polyethers (qv) have found some use, too, ia rigid urethane foams. 

Corrosion inhibitors are used to protect both the container and the metal substrate being stripped. Acid activated removers use inhibitors to block corrosion on active metals. Typical inhibitors are propylene oxide [75-56-9], butylene oxide [9106-88-7], triethylammonium phosphates, and sodium ben2oate [532-32-1] (see Corrosion and corrosion control). 

Polyall lene Oxide Block Copolymers. The higher alkylene oxides derived from propjiene, butylene, styrene (qv), and cyclohexene react with active oxygens in a manner analogous to the reaction of ethylene oxide. Because the hydrophilic oxygen constitutes a smaller proportion of these molecules, the net effect is that the oxides, unlike ethylene oxide, are hydrophobic. The higher oxides are not used commercially as surfactant raw materials except for minor quantities that are employed as chain terminators in polyoxyethylene surfactants to lower the foaming tendency. The hydrophobic nature of propylene oxide units, —CH(CH2)CH20—, has been utilized in several ways in the manufacture of surfactants. Manufacture, properties, and uses of poly(oxyethylene- (9-oxypropylene) have been reviewed (98). 

Certain block copolymers have also found appHcation as surfactants (88). Eor example, AB or ABA block copolymers in which one block is hydrophilic and one block is hydrophobic have proven useful for emulsifying aqueous and non-aqueous substances and for wetting the surface of materials. Examples of such surfactants are the poly(propylene oxide- /oi / -ethylene oxide) materials, known as Pluronics (BASC Wyandotte Co.). 

In most cases, these active defoaming components are insoluble in the defoamer formulation as weU as in the foaming media, but there are cases which function by the inverted cloud-point mechanism (3). These products are soluble at low temperature and precipitate when the temperature is raised. When precipitated, these defoamer—surfactants function as defoamers when dissolved, they may act as foam stabilizers. Examples of this type are the block polymers of poly(ethylene oxide) and poly(propylene oxide) and other low HLB (hydrophilic—lipophilic balance) nonionic surfactants. 

Block copolymers of ethylene oxide and propylene oxide, less hydrophilic than poly(oxyethylene) glycol and more reactive than the propylene oxide polymers, were introduced by Wyandotte Chemical (USA) under the trade name Pluronic. 

Surface active agents are important components of foam formulations. They decrease the surface tension of the system and facilitate the dispersion of water in the hydrophobic resin. In addition they can aid nucleation, stabilise the foam and control cell structure. A wide range of such agents, both ionic and non-ionic, has been used at various times but the success of the one-shot process has been due in no small measure to the development of the water-soluble polyether siloxanes. These are either block or graft copolymers of a polydimethylsiloxane with a polyalkylene oxide (the latter usually an ethylene oxide-propylene oxide copolymer). Since these materials are susceptible to hydrolysis they should be used within a few days of mixing with water. 

The initiator usually constitutes less than 1% of the final product, and since starting the process with such a small amount of material in the reaction vessel may be difficult, it is often reacted with propylene oxide to produce a precursor compound, which may be stored until required [6]. The yield of poloxamer is essentially stoichiometric the lengths of the PO and EO blocks are determined by the amount of epoxide fed into the reactor at each stage. Upon completion of the reaction, the mixture is cooled and the alkaline catalyst neutralized. The neutral salt may then be removed or allowed to remain in the product, in which case it is present at a level of 0.5-1.0%. The catalyst may, alternatively, be removed by adsorption on acidic clays or with ion exchangers [7]. Exact maintenance of temperature, pressure, agitation speed, and other parameters are required if the products are to be reproducible, thus poloxamers from different suppliers may exhibit some difference in properties. 

Ethylene oxide is an important intermediate chemical not only for the production of nonionic surfactants like fatty alcohol ethoxylates, alkylphenol ethoxy lates, or propylene oxide/ethylene oxide block copolymers, but also for manufacturing of anionic surfactants like alcohol ether sulfates. 

Linse, P, Phase Behavior of Poly(ethylene oxide)-Poly(propylene oxide) Block Copolymers in Aqueous Solutions, Journal of Physical Chemistry 97, 13896, 1993. 

Sulfonated or sulfomethylated lignins are reacted with phenol-blocking reagents, such as ethylene oxide, propylene oxide, or butylene oxide [1571]. 

There are also block copolymers from ethylene oxide and propylene oxide. 

A process for separating crude oil emulsions of the water-in-oil type based on certain ethylene oxide-propylene oxide block pol5miers and certain poly-glycidol ethers of phenol-formaldehyde-condensation products has been described [1026-1028]. 

The blend is partially crosslinked with a vinyl monomer when dissolved in an organic aprotic solvent and has a pH of 5.0 or lower. The first block copolymer is prepared by polycondensing a bis-hydroxyalkyl ether, such as dipropylene glycol, diethylene glycol, and the like, with propylene oxide. Next, the resulting propoxylated diol is reacted with ethylene oxide to produce the block copolymer. The second copolymer is prepared by polycondensing 2-amino-2-hydroxymethyl-1,3-propanediol, commonly known as TRIS, with... 

Block polymers or copolymers of ethylene oxide and 1,2-propylene oxide can be chain extended or crosslinked, respectively, with diisocyanates, dicarboxylic acids, formaldehyde, and diglycidyl ethers [108]. 

Statistical and block copolymers based on ethylene oxide (EO) and propylene oxide (PO) are important precursors of polyurethanes. Their detailed chemical structure, that is, the chemical composition, block length, and molar mass of the individual blocks may be decisive for the properties of the final product. For triblock copolymers HO (EO) (PO)m(EO) OH, the detailed analysis relates to the determination of the total molar mass and the degrees of polymerization of the inner PPO block (m) and the outer PEO blocks (n). 

On the basis of this approach, a triblock copolymer of ethylene oxide (EO) and propylene oxide (PO), HO(EO) (PO)m(EO) OH was analyzed with respect to the PPO inner block and the PEO outer blocks by LCCC and SEC (Adrian et al., 1998). For the selective separation of the block copolymer with respect to the PPO block, experiments were conducted using chromatographic conditions, corresponding to the critical point of PEO. These could be established on a RP-18 stationary phase when an eluent of methanol-water 86 14 (v/v) is used. The separation of the triblock copolymer at the critical point of PEO is shown in Fig. 17.15. 

Mean-field lattice theory proved to be capable of predicting the phase behaviour of the ternary block copolymer polyethylene-b-poly(propylene oxide)-b-poly(ethylene oxide), PE-b-PPO-b-PEO in the selective solvent water [164], The ethylene block is known to be highly hydrophobic, and its hydrophobicity does not depend strongly on temperature. The difference in hydrophobicity between PPO and PEO, on the other hand, is moderate... 

Block copolymers of /3-PL and /3-BL have been synthesized using (251), although reaction times of several weeks are required.782 Since (TPP)Al-based carboxylates are also known to polymerize epoxides (see Section 9.1.7.2), the sequential addition of /3-BL and propylene oxide (PO) results in formation of a p(/3-BL-/3-PO) diblock.782 However, reversing the order of addition fails to produce the block copolymer since the propagating alkoxide (TPP)Al(OCHMeCH2)nCl does not initiate the ROP of /3-BL. 

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