Polyether triols block copolymers

The synthesis of polyether triols, block copolymers with terminal poly[EO] block is relatively simple in the first step a propoxylated intermediate polyether is synthesised by the polyaddition of PO to the starter (glycerol or propylene glycol). After the addition of the required quantity of PO, the unreacted monomer is eliminated by vacuum distillation and the polymerisation continues by the addition of EO, the second monomer. 

Polyether triol, block copolymer PO-EO, with terminal poly[EO] block... 

Figure 4.23 Variation of primary hydroxyl content as a function of EO content in polyether triols block copolymers [PO-EO] with terminal poly[EO] block MW = 5000 daltons catalyst KOH - 0.0056 mol%...

Figure 4.28 The structures of polyether triol block copolymers PO-EO a) terminal poly[EO)] block b) poly[EO] block linked to the starter c) internal poly[EO] block...

The pseudoliving character of PO anionic polymerisation produces a large variety of block copolymers, by simply changing the nature of the oxirane monomer because the catalytic species (potassium alcoholate) remains active during and after the polymerisation reaction. Thus, if a polyether is synthesised first by anionic polymerisation of PO and the polymerisation continues with another monomer, such as EO, a block copolyether PO-EO with a terminal poly[EO] block is obtained. Another synthetic variant is to obtain a polyethoxylated polyether first by the anionic polymerisation of EO initiated by glycerol [108], followed by the addition of PO to the resulting polyethoxylated triol. A block copolyether PO-EO is obtained with internal poly[EO] block linked to the starter. Another possibility is to add the monomers in three steps first PO is added to glycerol, followed by EO addition and finally by the addition of PO. A copolyether triol block copolymer PO-EO with the internal poly[EO] block situated inside the polyetheric chain between two poly[PO] blocks is obtained [4, 100, 101]. 

The polyether diols, block copolymers of PO-EO with terminal poly[EO] block are obtained absolutely identically to the previously described EO capped polyether triols, the difference being that the propoxylated intermediate is a propoxylated polyether diol. 

Table 4.12 Characteristics of polyether triol, based copolymers (terminal block) with a MW of on glycerol PO-EO block 5000-6500 daltons...

By using two oxiranic monomers, such as PO and EO, it is possible to obtain a great variety of polyether polyols homopolymers of PO, block copolymers PO-EO (with terminal or internal poly[EO] block) or random copolymers (heteropolyethers) of PO-EO, diols or triols of different MW. 

The polyether triols are the most important class of polyether polyols and they are used in flexible PU foam fabrication. The majority of polyether triols used in flexible foams are copolymers of PO-EO. Random copolymers are used in continuous slabstock flexible foams and block copolymers (PO-EO), with terminal poly[EO] block, are used in moulded foams (hot moulding and cold cure moulding processes). 

Figure 4.24 Graphical representation of Equation 4.17 in the form of a straight line, at polyether triols of MW of 5000 daltons, block copolymers PO-EO with terminal poly[EO] block Distribution constant K = 14...

The most important polyether triol, PO-EO block copolymers with poly[EO] block, used in practice, are ... 

The polyether triols (PO-EO block copolymers with terminal poly[EO] block) are very reactive polyols due to the presence of a high percentage of primary hydroxyls. These polyether polyols with terminal poly[EO] block, are used preferentially for moulded flexible PEI foams. 

Hydroxy-terminated polyethers have now assumed a dominant role in the commercial production of polyurethanes. The most widely used polyethers are derivatives of propylene oxide and these polymers are described in Section 8.4.3.1. Linear, glycol-initiated propylene oxide polymers and propylene oxide-ethylene oxide block copolymers find some use in the preparation of elastomers. Polyether triols of relatively high molecular weight (about 3000) are extensively used for the production of flexible foams whilst polyols of low molecular weight (about 500) are used for rigid foams and surface coatings. Poly(oxytetramethylene) glycols prepared from tetrahydrofuran (Section 8.4.6) are used for the preparation of elastomers and spandex fibres. 

Polyoxypropylene (9). See PPG-9 Polyoxypropylene (12). SeePPG-12 Polyoxypropylene (17). SeePPG-17 Polyoxypropylene (20). See PPG-20 Polyoxypropylene (26). See PPG-26 Polyoxypropylene (30). See PPG-30 Polyoxypropyleneamine. See Polyether polyol Polyoxypropylene (3) methyl ether. See PPG-3 methyl ether Polyoxypropylene/pdyoxyelhylene block polymer Polyoxypropylene/ polyoxyethylene copolymer. See EO/PO block polymer or copolymer Polyoiqrpropylene triol. See Polyether polyol Poly (oxytetramethylene) Poly (oxytetramethylene) diol. See Polytetramethylene ether glycol... 

Polyoxyl 20 stearate. See PEG-20 stearate Polyoxyl 40 stearate. See PEG-40 stearate Polyoxyl 50 stearate. See PEG-50 stearate Polyoxyl 55 stearate. See PEG-55 stearate Polyoxymethylene glycols. See Formaldehyde Poly [oxy(methylsilylene)]. See Methicone Polyoxypropylene (9). See PPG-9 Polyoxypropylene (12). See PPG-12 Polyoxypropylene (17). See PPG-17 Polyoxypropylene (20). See PPG-20 Polyoxypropylene (26). See PPG-26 Polyoxypropylene (30). See PPG-30 Polyoxypropylene (34). See PPG-34 Polyoxypropylene (40). See PPG-40 Polyoxypropyleneamine. See Polyether polyol Polyoxypropylene (3) methyl ether. See PPG-3 methyl ether Polyoxypropylene/polyoxyethylene block polymer Polyoxypropylenefpolyoxy-ethylene copolymer. See EOfPO block polymer or copolymer Polyoxypropylene triol. See Polyether polyol Polyphosphoric acid, ammonium saH. See Ammonium polyphosphate Polyphosphoric acids, compds. with triethanolamine Polyphosphoric acids, esters with triethanolamine. See TEA-polyphosphate Polyphosphoric acid sodium saH. See Sodium polyphosphate Polyphosphoric acids, potassium saHs. See Potassium polyphosphate Polyphosphoric acids, sodium salts. See Sodium polyphosphate Polyphosphoric acid, triethanolamine ester. See TEA-polyphosphate Polypropene. See Polypropylene Polypropylene CAS 90034)7-0... 

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