Heteropolyethers

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 random copolyether triols PO-EO, usually called heteropolyether polyols, with a MW of 3000-3600 daltons, are the most important polyether polyols for flexible PU slabstock foams, generally used in furniture industry. The worldwide consumption of flexible PU foams is presented in Figure 4.16. 

For continuous flexible PU slabstock production, the heteropolyether triols PO-EO are considered universal polyols used in conventional soft and supersoft flexible PU foams, covering a large range of densities (12-40 kg/m3) and load bearing properties. 

The 13C NMR study of a heteropolyether polyol (MW 3600 daltons) containing 15% EO units proved that 45% of total EO units have a microblock structure (...PO-EO-EO-PO..) and that 55% of total EO units are alternating sequences of PO-EO-PO units [97]. 

The general structure of random copolymers of PO-EO and copolyether triols (PO-EO) is presented in Figure 4.18. The main characteristics of the random copolymers of PO-EO, heteropolyether triols, which are used most, are presented in Table 4.7. 

Figure 4.18 The general structure of random copolymers of PO-EO (heteropolyether triols)...

Table 4.7 The main characteristics of polyether triol random copolymers (PO-EO heteropolyether polyols) ...

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