Investigation of chemical stability of ether-urethane prepolymers

The ether-urethane prepolymers based on oligoetherol ("Rokopol D 2002" or "PTMG 1000") and excess of diphenylmethane diisocyanate (Table 1) were prepared. The effects of viscometer pin rotation speed, temperature, NCO groups percentage and the type of oligoetherol used on the viscosity of the products were determined (Fig. 1-3). The stability of prepolymers discussed during four-week storage (change of free NCO groups' content, Fig. 4 and 5) has been evaluated. It was found that the use of "PTMG 1000" in the synthesis significantly increased the product stability. The chemical structures of prepolymers obtained were confirmed by FT-IR method (Fig. 6).